https://www.echeat.com/ Arthur was face-to-face with an enormous white snake, whose black eyes were looking at him as its prey. Arthur was so surprised that he couldn't even move, where did he came from, it just appeared out of nowhere in his way just before he would come to...the king! -Behold beast, get out of my way or you'll feel my sword's edge !!! he exclamated while he was unsheating his sword, Light. The snake, as if he wasn't hearing anything, atacked Arthur with his mouth wide opened. Arthur dodged and atacked it's head, but his sword broked at the contact with it's skin, letting Arthur shocked. It wasn't only it's skin, from both of his theeth was pouring venim, which at the contact with the stone and disintegrated it. The snake tried another atack but Arthur dodged in the last moment. -If i can't cut you then I will let you moveless, he said with anger. And so he started to move between pilars, with the snake following him and trying to bite him. After a few minutes of running and dodging Arthur finally stoped, the snake, although it was longer than expected, he managed to imobilise it at least for a few minutes. -I have to go to my king, he must be in danger, ge said while running to the main hall. While he was running he saw that the sentinels were dead, and most of the soldiers were in a struggle against death, and they were losing. He wanted to help them, but there was no time. When he finally arrived at the main hall he saw a nightmare: the king and the queen weren't just dead, they were rottening at such a fast rate that he thought it wasn't true. He approached to them and fell on his knees. Without realising it, he was holding the king's and queen's heads on his arms. -I...failed...to protect you both...I failed... -Indeed you failed, a cold voice heared from the shadows, you are pathetic Arthur, and naive. It was a warrior, just like Arthur, but he has a snake emblem on his black armor and a white snake-like sword. -You...! You killed them !?! -Of course I do! Also I will finish you too. Arthur grabbed the king's sword and atacked him in a flash, but the snake warrior dodged, grabbed Arthur's face then smashed him on the floor, cracking half of the floor. Arthur coughed blood and paralised of fear. The 2016-05-27T04:03:35.64-04:00 http://75.150.148.189/free-essay/Aliphatic-Solvents-in-Asia-Market-Trends,-Size,-Challenges,-Costs-and-Price,-Analysis,-Segmented-Overview-and-Outlook-35198.aspx {{YOURNAME}} {{PERIOD}} Factors that Affect the Rate of Reaction Data Table 1. Effect of Various Levels of Molarity of Acid on the Speed of Reaction Concentration (milliliters of gas per minute) Molarity of Acid Trial 1 Trial 2 Trial 3 Average 0.5 M 2.7 1.98 2.04 2.16 1 M 18 19.14 19.78 18.97 2 M 35.43 33.09 33.33 33.95 This data 2015-09-21T22:37:01.507-04:00 http://75.150.148.189/free-essay/Concentration-of-Acid-Lab-Conclusion-35136.aspx Alexander Kollmann 9E D Assessment - Sulfuric Acid Mr. Curran 09.03.2015 Introduction Sulfuric Acid, also known as Oil of Vitriol to medieval European alchemists, is a colourless, greasy, dence and also corrosive liquid, that has the chemical formula of H2SO4. It is arguably one of the most important chemicals, that can be used for important things that benefit society to many extents. It can be prepared industrially, with the reaction of water and sulfur trioxide, which can be made by reacting sulfur dioxide and oxygen by using either a chamber process or a contact process. It is produced in a larger scale due to it’s beneficial contribution to the production of fertilizers, dyes, pigments, drugs, detergents, explosives as well as inorganic salts. It is always soluble in water in all concentrations. How have scientists managed, to a feasible extent, managed to produce Sulfuric Acid on a larger scale safely without causing excess environmental damage ? Furthermore, how what have the social, economic and political impacts been regarding the production of Sulfuric Acid ? In this essay, i will talk about how Sulfuric Acid is produced on a large scale, and how it’s feasible production grant it such success in the industry. Furthermore, I will also explore the effects and impacts the production of Sulfuric Acid has on a Economic, political, social and ethical basis. How is Sulfuric Acid made ? In my introduction, I wrote that sulfuric acid can be produced either through the chamber process or the contact process. Here, I will be explaining and describing how sulfuric acid can be produced using the contact process. The raw materials needed in order to produce sulfuric acid are air, water and sulfur. The contact process, that is needed in order to produce the liquid, is a process that involves a reversible reaction i.e. a chemical reaction that can go both ways. 1 ) As a first step in the production of sulfuric acid, sulfur is burned, in order to produce the chemical compound Sulfur Dioxide. (l) means liquid and (g) means gas This, not yet is a reversible reaction. During this process, be sure not to release any sulfur dioxide, as this can contribute to acid rain, rain that contains dissolved acidic gases such as nitrogen oxides and sulfur dioxide. 2) As a second step in the production of Sulfuric Acid, more oxygen has to be reacted with Sulfur Dioxide in order to create sulfur trioxide. ?H=-196 kJ/mol This reaction 2015-03-15T15:38:09.61-04:00 http://75.150.148.189/free-essay/Sulfuric-Acid-Everything-you-need-to-know-35095.aspx TOPIC 10 ORGANIC CHEMISTRY 10. 1 Introduction Homologous series A homologous series is a set of compounds which has the following features: ? share a general formula (i.e. same elements in the same ratio); ? members share the same functional group; a functional group is a group of atoms which determine the chemical properties of the homologous series; ? whose nearest neighbours differ by one repeating unit, most often a methyl group -(CH3 ) or a methylene group -(CH2)- ; ? have similar chemical properties (same functional group); ? show a gradual change (gradation) in physical properties as shown by the table below which shows the melting points and boiling points of some alkanes: ? examples of homologous series: alkanes, alkenes, alkynes, alcohols, esters, alkanals and amines. name molecular formula melting point (oC) boiling point (oC) state at 25oC methane CH4 -183 -164 gas ethane C2H6 -183 -89 propane C3H8 -190 -42 butane C4H10 -138 -0.5 pentane C5H12 -130 36 liquid hexane C6H14 -95 69 heptane C7H16 -91 98 octane C8H18 -57 125 nonane C9H20 -51 151 decane C10H22 -30 174 undecane C11H24 -25 196 dodecane C12H26 -10 216 eicosane C20H42 37 343 solid triacontane C30H62 66 450 The table on the left shows a gradual increase in boiling point with increasing number of carbon atoms and therefore increasing molar mass. A trend caused by the fact that as the number of carbon atoms in the molecules increases so does the number of electrons within the compound which creates greater polarity during instantaneous polarisation (which causes the Van der Waals’ forces) and therefore produces greater Van der Waals’ forces. There is also a greater surface area over which instantaneous polarization can occur. A graph of boiling points of alkanes against chain length gives a steep line at first but then flattens out at higher numbers of carbon atoms suggesting that the size of molecules becomes less influential in affecting boiling point. Formula of organic compounds type of formula description example empirical formula shows most simple ratio CH2 molecular formula shows the different atoms and how many of each; no information on how they are arranged. C6H14 structural formula structural formula show how atoms are arranged together in the molecule; a full structural formula (sometimes called a graphic formula or displayed formula) shows every atom and bond. condensed structural formula structural formula which shows order in which atoms are arranged but which omits bonds CH3CH2CH2CH2CH2CH3 or CH3(CH2)4CH3 Naming of organic compounds When naming an organic compound we want to give a lot of information in its name which is why the name of an organic compound consists of at least two parts: one to indicate the number of carbon atoms in the chain and the other the functional group. Other parts will indicate length and number of branches or if the compound is cyclic. Example: eth ane • this part tells us how many carbons atoms there are in the molecule; • this part 2015-01-24T18:19:49.66-05:00 http://75.150.148.189/free-essay/Organic-Chemistry-35078.aspx 2014-03-08T05:25:54.703-05:00 http://75.150.148.189/free-essay/-THE-DETERMINATION-OF-THE-PERCENT-WATER-IN-A-COMPOUND-35006.aspx The Haber process, also called the Haber–Bosch process, is the industrial implementation of the reaction of nitrogen gas and hydrogen gas. It is the main industrial route to ammonia: N2 + 3 H2 ? 2 NH3 (?H = -92.4 kJ·mol-1) Nitrogen is a critical limiting mineral nutrient in plant growth. Carbon and oxygen are also critical, but are easily obtained by plants from soil and air. Even though air is 78% nitrogen, atmospheric nitrogen is nutritionally unavailable because nitrogen molecules are held together by strong triple bonds. Nitrogen must be 'fixed', i.e. converted into some bioavailable form, through natural or man-made processes. It was not until the early 20th century that Fritz Haber developed the first practical process to convert atmospheric nitrogen to ammonia, which is nutritionally available. Prior to the discovery of the Haber process, ammonia had been difficult to produce on an industrial scale. Fertilizer generated from ammonia produced by the Haber process is estimated to be responsible for sustaining one-third of the Earth's population.[6] It is estimated that half of the protein within human beings is made of nitrogen that was originally fixed by this process; the remainder was produced by nitrogen fixing bacteria and archaea. History Main article: History of the Haber process Early in the twentieth century, several chemists tried to make ammonia from atmospheric nitrogen. German chemist Fritz Haber discovered a process that is still used today. Robert Le Rossignol was instrumental in the development of the high-pressure devices used in the Haber process.[8] They demonstrated their process in the summer of 1909 by producing ammonia from air drop by drop, at the rate of about 125 ml (4 US fl oz) per hour. The process was purchased by the German chemical company BASF, which assigned Carl Bosch the task of scaling up Haber's tabletop machine to industrial-level production.[3][9] Haber and Bosch were later awarded Nobel prizes, in 1918 and 1931 respectively, for their work in overcoming the chemical and engineering problems posed by the use of large-scale, continuous-flow, high-pressure technology. Ammonia was first manufactured using the Haber process on an industrial scale in 1913 in BASF's Oppau plant in Germany, production reaching 20 tonnes/day the following year.[10] During World War I, the synthetic ammonia was utilized for the production of nitric acid, a precursor to munitions. The Allies had access to large amounts of sodium nitrate deposits in Chile (so called "Chile saltpetre") that belonged almost totally to 2013-09-14T05:09:31.847-04:00 http://75.150.148.189/free-essay/Haber-process-34961.aspx Water cycle The water cycle, also known as the hydrologic cycle or the H2O cycle, describes the continuous movement of water on, above and below the surface of the Earth. Although the balance of water on Earth remains fairly constant over time, individual water molecules can come and go, in and out of the atmosphere. The water moves from one reservoir to another, such as from river to ocean, or from the ocean to the atmosphere, by the physical processes of evaporation, condensation, precipitation, infiltration, runoff, and subsurface flow. In so doing, the water goes through different phases: liquid, solid (ice), and gas (vapor). The water cycle involves the exchange of energy, which leads to temperature changes. For instance, when water evaporates, it takes up energy from its surroundings and cools the environment. When it condenses, it releases energy and warms the environment. These heat exchanges influence climate. By transferring water from one reservoir to another, the water cycle purifies water, replenishes the land with freshwater, and transports minerals to different parts of the globe. It is also involved in reshaping the geological features of the Earth, through such processes as erosion and sedimentation. Finally, the water cycle figures significantly in the maintenance of life and ecosystems. As the Earth's surface water evaporates, winds move water in the air from the sea to the land, increasing the amount of fresh water on land. Water vapor is converted to clouds that bring fresh water to land in the form of rain or snow. Precipitation falls on the ground, but what happens to that water depends greatly on the geography of the land at any particular place. Description[edit] The Sun, which drives the water cycle, heats water in oceans and seas. Water evaporates as water vapor into the air. Ice and snow can sublimate directly into water vapor. Evapotranspiration is water transpired from plants and evaporated from the soil. Rising air currents take the vapor up into the atmosphere where cooler temperatures cause it to condense into clouds. Air currents move water vapor around the globe, cloud particles collide, grow, and fall out of the upper atmospheric layers as precipitation. Some precipitation falls as snow or hail, sleet, and can accumulate as ice caps and glaciers, which can store frozen water for thousands of years. Most water falls back into the oceans or onto land as rain, where the water flows over the ground as surface runoff. A portion 2013-06-23T03:35:25.883-04:00 http://75.150.148.189/free-essay/Water-Cycle-34899.aspx Green chemistry, also called sustainable chemistry, is a philosophy of chemical research and engineering that encourages the design of products and processes that minimize the use and generation of hazardous substances.[1] Whereas environmental chemistry is the chemistry of the natural environment, and of pollutant chemicals in nature, green chemistry seeks to reduce and prevent pollution at its source. As a chemical philosophy, green chemistry applies to organic chemistry, inorganic chemistry, biochemistry, analytical chemistry, and even physical chemistry. While green chemistry seems to focus on industrial applications, it does apply to any chemistry choice. Click chemistry is often cited as a style of chemical synthesis that is consistent with the goals of green chemistry. The focus is on minimizing the hazard and maximizing the efficiency of any chemical choice. It is distinct from environmental chemistry which focuses on chemical phenomena in the environment. In 2005 Ryoji Noyori identified three key developments in green chemistry: use of supercritical carbon dioxide as green solvent, aqueous hydrogen peroxide for clean oxidations and the use of hydrogen in asymmetric synthesis.[2] Examples of applied green chemistry are supercritical water oxidation, on water reactions, and dry media reactions. Bioengineering is also seen as a promising technique for achieving green chemistry goals. A number of important process chemicals can be synthesized in engineered organisms, such as shikimate, a Tamiflu precursor which is fermented by Roche in bacteria. The term green chemistry was coined by Paul Anastas in 1991.[3] Principles [edit] Paul Anastas, then of the United States Environmental Protection Agency, and John C. Warner developed 12 principles of green chemistry,[4] which help to explain what the definition means in practice. The principles cover such concepts as: the design of processes to maximize the amount of raw material that ends up in the product; the use of safe, environment-benign substances, including solvents, whenever possible; the design of energy efficient processes; the best form of waste disposal: not to create it in the first place. The 12 principles are: It is better to prevent waste than to treat or clean up waste after it is formed. Synthetic methods should be designed to maximize the incorporation of all materials used in the process into the final product. Wherever practicable, synthetic methodologies should be designed to use and generate substances that possess little or no toxicity to human health and the environment. Chemical products should be designed to preserve efficacy of function while reducing toxicity. The use of auxiliary substances (e.g. solvents, separation agents, etc.) should be made 2013-05-07T00:54:41.187-04:00 http://75.150.148.189/free-essay/Green-Chemistry-34879.aspx The atom is a basic unit of matter that consists of a dense central nucleus surrounded by a cloud of negatively charged electrons. The atomic nucleus contains a mix of positively charged protons and electrically neutral neutrons (except in the case of hydrogen-1, which is the only stable nuclide with no neutrons). The electrons of an atom are bound to the nucleus by the electromagnetic force. Likewise, a group of atoms can remain bound to each other by chemical bonds based on the same force, forming a molecule. An atom containing an equal number of protons and electrons is electrically neutral, otherwise it is positively or negatively charged and is known as an ion. An atom is classified according to the number of protons and neutrons in its nucleus: the number of protons determines the chemical element, and the number of neutrons determines the isotope of the element.[1] Chemical atoms, which in science now carry the simple name of "atom," are minuscule objects with diameters of a few tenths of a nanometer and tiny masses proportional to the volume implied by these dimensions. Atoms can only be observed individually using special instruments such as the scanning tunneling microscope. Over 99.94% of an atom's mass is concentrated in the nucleus,[note 1] with protons and neutrons having roughly equal mass. Each element has at least one isotope with an unstable nucleus that can undergo radioactive decay. This can result in a transmutation that changes the number of protons or neutrons in a nucleus.[2] Electrons that are bound to atoms possess a set of stable energy levels, or orbitals, and can undergo transitions between them by absorbing or emitting photons that match the energy differences between the levels. The electrons determine the chemical properties of an element, and strongly influence an atom's magnetic properties. The principles of quantum mechanics have been successfully used to model the observed properties of the atom. EtymologyThe name atom comes from the Greek ?t?µ?? (atomos, "indivisible") from ?- (a-, "not") and t?µ?? (temno, "I cut"),[3] which means uncuttable, or indivisible, something that cannot be divided further.[4] The concept of an atom as an indivisible component of matter was first proposed by early Indian and Greek philosophers. In the 18th and 19th centuries, chemists provided a physical basis for this idea by showing that certain substances could not be further broken down by chemical methods, and they applied the ancient philosophical 2013-02-02T08:18:05.007-05:00 http://75.150.148.189/free-essay/Atomic-Structure-34787.aspx Hydrogen 1H - ? H ? Li Periodic table - ? hydrogen ? helium Appearance colorless gas Purple glow in its plasma state Spectral lines of hydrogen General properties Name, symbol, number hydrogen, H, 1 Pronunciation /'ha?dr?d??n/ HY-dr?-j?n[1] Element category nonmetal Group, period, block 1, 1, s Standard atomic weight 1.008(1) Electron configuration 1s1 1 History Discovery Henry Cavendish[2][3] (1766) Named by Antoine Lavoisier[4] (1783) Physical properties Color colorless Phase gas Density (0 °C, 101.325 kPa) 0.08988 g/L Liquid density at m.p. 0.07 (0.0763 solid)[5] g·cm-3 Liquid density at b.p. 0.07099 g·cm-3 Melting point 14.01 K, -259.14 °C, -434.45 °F Boiling point 20.28 K, -252.87 °C, -423.17 °F Triple point 13.8033 K (-259°C), 7.042 kPa Critical point 32.97 K, 1.293 MPa Heat of fusion (H2) 0.117 kJ·mol-1 Heat of vaporization (H2) 0.904 kJ·mol-1 Molar heat capacity (H2) 28.836 J·mol-1·K-1 Vapor pressure P (Pa) 1 10 100 1 k 10 k 100 k at T (K) 15 20 Atomic properties Oxidation states 1, -1 (amphoteric oxide) Electronegativity 2.20 (Pauling scale) Ionization energies 1st: 1312.0 kJ·mol-1 Covalent radius 31±5 pm Van der Waals radius 120 pm Miscellanea Crystal structure hexagonal Magnetic ordering diamagnetic[6] Thermal conductivity 0.1805 W·m-1·K-1 Speed of sound (gas, 27 °C) 1310 m·s-1 CAS registry number 1333-74-0 Most stable isotopes Main article: Isotopes of hydrogen iso NA half-life DM DE (MeV) DP 1H 99.985% 1H is stable with 0 neutrons 2H 0.015% 2H is stable with 1 neutron 3H trace 12.32 y ß- 0.01861 3He v ·t ·e· r Hydrogen is a chemical element with symbol H and atomic number 1. With an average atomic weight of 1.00794 u (1.007825 u for hydrogen-1), hydrogen is the lightest element and its monatomic form (H1) is the most abundant chemical substance, constituting roughly 75% of the Universe's baryonic mass.[7] Non-remnant stars are mainly composed of hydrogen in its plasma state. At standard temperature and pressure, hydrogen is a colorless, odorless, tasteless, non-toxic, nonmetallic, highly combustible diatomic gas with the molecular formula H2. Naturally occurring atomic hydrogen is rare on Earth because hydrogen readily forms covalent compounds with most elements and is present in the water molecule and in most organic compounds. Hydrogen plays a particularly important role in acid-base chemistry with many reactions exchanging protons between soluble molecules. In ionic compounds, it can take a negative charge (an anion known as a hydride and written as H-), or 2012-11-22T08:52:01.043-05:00 http://75.150.148.189/free-essay/Hydrogen-34751.aspx Other names Carbonic acid gas Carbonic anhydride Carbonic oxide Carbon oxide Carbon(IV) oxide Dry ice (solid phase) Properties Molecular formula CO2 Molar mass 44.01 g mol-1 Appearance Colorless gas Odor Odorless Density 1562 kg/m3 (solid at 1 atm and -78.5 °C) 770 kg/m3 (liquid at 56 atm and 20 °C) 1.977 kg/m3 (gas at 1 atm and 0 °C) Melting point -78 °C, 194.7 K, -109 °F (subl.) Boiling point -57 °C, 216.6 K, -70 °F (at 5.185 bar) Solubility in water 1.45 g/L at 25 °C, 100 kPa Acidity (pKa) 6.35, 10.33 Refractive index (nD) 1.1120 Viscosity 0.07 cP at -78.5 °C Dipole moment zero Structure Molecular shape linear Thermochemistry Std enthalpy of formation ?fHo298 -393.5 kJ·mol-1 Standard molar entropy So298 214 J·mol-1·K-1 Hazards MSDS External MSDS NFPA 704 020 Related compounds Other anions Carbon disulfide Carbon diselenide Other cations Silicon dioxide Germanium dioxide Tin dioxide Lead dioxide Related carbon oxides Carbon monoxide Carbon suboxide Dicarbon monoxide Carbon trioxide Related compounds Carbonic acid Carbonyl sulfide Supplementary data page Structure and properties n, er, etc. Thermodynamic data Phase behaviour Solid, liquid, gas Spectral data UV, IR, NMR, MS Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox references Carbon dioxide (chemical formula CO2) is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. It is a gas at standard temperature and pressure and exists in Earth's atmosphere in this state, as a trace gas at a concentration of 0.039 per cent by volume.[1] As part of the carbon cycle known as photosynthesis, plants, algae, and cyanobacteria absorb carbon dioxide, light, and water to produce carbohydrate energy for themselves and oxygen as a waste product.[2] But in darkness photosynthesis cannot occur, and during the resultant respiration small amounts of carbon dioxide are produced.[3] Carbon dioxide is also produced by combustion of coal or hydrocarbons, the fermentation of liquids and the breathing of humans and animals. In addition it is emitted from volcanoes, hot springs, geysers and other places where the earth’s crust is thin; and is freed from carbonate rocks by dissolution. CO2 is also found in lakes at depth under the sea, and commingled with oil and gas deposits.[4] The environmental effects of carbon dioxide are of significant interest. In the earth's atmosphere, it acts as a greenhouse gas which plays a major role in global warming and anthropogenic climate change. Also a major source of ocean acidification is CO2 2012-11-22T08:34:18.727-05:00 http://75.150.148.189/free-essay/Carbon-dioxide-34748.aspx Fractional Distillation Of Crude Oil Fractional distillation differs from distillation only in that it separates a mixture into a number of different parts, called fractions. A tall column is fitted above the mixture, with several condensers coming off at different heights. The column is hot at the bottom and cool at the top. Substances with 2012-10-25T10:52:04.487-04:00 http://75.150.148.189/free-essay/Fractional-Distillation-Of-Crude-Oil-34722.aspx This paper discusses the chemistry of the human cell. (3 pages; 5 sources; MLA citation style) I Introduction The cells of the human body are complex structures that perform the chemical reactions necessary to sustain life. This paper briefly describes cell chemistry. II Discussion A cell has three main components: the cell membrane, the cytoplasm (the substance of the cell—water, salt and “macromolecules”); and the nucleus. The cell membrane is comprised of lipids and proteins; it gives the cell its shape, protects the contents, and “controls what goes in and out of the cell.” (“Inside the Living Cell,” PG). (An indication of the importance of this transmission is the fact that this year’s Nobel Prize in Chemistry went to Dr. Peter Agre and Dr. Roderick MacKinnon for their work with the “channels” in cell membranes.) (“Nobel Prize in Chemistry Winners,” PG). Human cells are really chemical engines; they perform the chemical reactions necessary to sustain life. In this process, there are only six “major players”: carbon, hydrogen, oxygen, nitrogen, sulfur, and phosphorus. It is carbon that is the major “building block” here, because it is a “unique element” that can combine with many other atoms to form strong, stable chemical bonds. It can take many forms, making long chains that double back on each other, for instance; it provides a “skeleton” that other atoms bond to. The gigantic molecules formed when atoms of hydrogen, oxygen and others bond to the carbon skeleton are called “macromolecules”, and lipids and proteins are both macromolecules formed by this process. (“The Chemistry of the Cell,” PG). As we’ve seen, they are found in the cell walls, where they help with transmission of materials to and from the cell. Macromolecules are made up of “smaller, repeating submits” that are known as “monomers.” These monomers are always similar in chemical structure, though they are not always identical. (Simple sugar is a monomer.) In a process called “polymerization,” the monomers are joined by a series of chemical reactions. The result of these reactions is the formation of large, complex molecules known as polymers. Lipids are polymers; examples are fats, oils and wax. (“The Chemistry of the Cell,” PG). Polymerization allows for a tremendous range of chemical diversity in living things, in much the same way that the alphabet, though limited to 26 letters, can create 2011-10-26T13:14:25.29-04:00 http://75.150.148.189/free-essay/Cellular-Chemistry-34109.aspx Chinese researchers have found further evidence that plants emit significant quantities of methane - a potent greenhouse gas. But the latest findings also show that methane emissions depend not just on the species of plant, but the conditions in which they are 2008-09-08T21:38:57-04:00 http://75.150.148.189/free-essay/Grasslands-Emit-Greenhouse-Gas-33700.aspx Editorial: Liquid asset One third of the world's population already lives in water-scarce areas. And stocks of water are dwindling: not only because a burgeoning population needs to quench its thirst, but also to meet increasing agricultural demands for crop growth. Add to that the water demands of low-carbon alternatives to fossil fuels, including biofuels and hydrogen (see Chemistry World , May 2008, p12), and industry's insatiable appetite for water, and it's clear demand is rapidly overwhelming supply. Many predict that the major conflicts of the coming century will be fought over water. And the unpredictable impacts of climate change mean that we cannot simply rely on surface water resources to continue to be replenished by rain. Time to compromise The issue is not just quantity, it's quality. Urban pressure on water supplies means more and more people are quite literally tapping the same sources - and also that water treatment has to cope with a swathe of previously undiscovered pollutants (see p48). Many of these, including active pharmaceuticals, simply slip through traditional water treatment systems. More advanced purification systems are already in existence that are capable of removing almost all of them, but at what cost? There are questions to be answered about the impact of new pollutants before money is spent on removing them. Only the best scientific advice will aid the development of good water management, which, in some cases is going to prove very expensive indeed. There will often be simpler solutions: it cannot be sensible for people in many developed countries to continue to use high quality, drinkable water to flush toilets and water lawns while more than one in six people throughout the world have no access at all to safe, clean drinking water. The scientific community must play a key role in deciding in which direction the money flows (see p44). In the aquatic environment, we have already seen the effects of some wastewater compounds on ecosystems - certain hormones that we regularly flush away, for example, have been found to affect the development of fish, and to reduce their rates of reproduction. We have a moral obligation to monitor these effects and their causes closely. Only through rigorous and well coordinated environmental monitoring can we really know which compounds pose a serious threat to ourselves and our environment (see p54). Less is more The appetite for water is most 2008-09-08T21:38:12-04:00 http://75.150.148.189/free-essay/Chemistry-article-retel-2-33699.aspx Gold's magic number 20 August 2008 A new gold catalyst developed by UK chemists can catalyze hydrocarbon oxidation, using O2 as the only oxidant. But catalyst particle size is critical - above 2nm diameter, the catalyst loses all activity. The catalyst was developed by Richard Lambert and colleagues at the University of Cambridge, who used styrene oxidation as a test reaction. The team found that the reaction didn't require any additional oxidants such as peroxides. Oxygen molecules adsorbed to the gold particles, and then dissociated to give single oxygen atoms that initiated the styrene oxidation. 'Styrene is a very good test molecule which can be handled easily,' says Marc Armbrüster, who also works at the University of Cambridge and collaborates with the group. Oxygenated hydrocarbons are also valuable intermediates for industry. 'The prospect of selective oxidation using molecular oxygen without the addition of additives over a new catalyst is exciting,' comments Jeroen van Bokhoven, from the Institute for Chemical and Bioengineering at ETH Zurich, Switzerland. 'There seems to be space for trying the catalyst out on more systems and for improving the selectivity,' van Bokhoven adds. The catalyst consists of 55-atom gold clusters, which form nanometer-sized particles on inert supports. The Au55 particles are so-called 'magic number' clusters that contain exactly the right number of atoms for very stable geometries, making them ideally suited to catalysis. However, the particle size of the catalyst is critical. While 1.4nm diameter particles were effective and robust catalysts, particles 2nm or larger have no catalytic activity. The researchers used x-ray photoelectron spectroscopy to show that the nano-clusters have a different electronic structure to bulk gold. 'As the particles become smaller, their electronic structure changes significantly,' explains Armbrüster. The organic reactant only weakly adsorbs to the catalyst, so that its electronic structure is not perturbed. 'We don't know exactly how the catalyst works but we really want to understand what is going on,' says Armbrüster. 'We think that quantum chemistry might be the easiest way to find out what is happening,' he adds. 'We also need to do further lab work, for example to discover the catalyst's lifetime and to establish the influence of different loadings of the catalyst.' The research team hopes that its gold clusters will provide a route to the synthesis of robust gold catalysts with practical applications for synthetic chemistry. 'We are quite some way off an industrial catalyst, but we see no barrier to gold clusters 2008-09-08T21:36:50-04:00 http://75.150.148.189/free-essay/Chemistry-Article-Summary-33698.aspx {INTRODUCTION} This essay is about blood transfusion, and blood types. Blood is a combination of biological fluid which contains of red blood cells, white blood cells and the fluid known as blood plasma. Red blood cells are the most common type of blood cell and the main objective is delivering oxygen from the lungs to all the organs in your body. White blood cells are cells which defend the body against infectious, disease, viruses and foreign materials. Blood transfusion is the process of transferring blood or blood based products from one person into another person. {RED BLOOD CELLS} The red blood cells are extremely important to the body. The body relies on red blood cells to deliver oxygen to brain tissue, muscle tissue, and all of your organs. Oxygen to your body is like fuel to a car, with out fuel the car will shut down. And the same thing will happen to your body; but with a more fatal result. Un-oxygenated blood becomes darker and looks more purplish than it dues red. {WHITE BLOOL CELLS} The white blood cells play a whole different part in your biological makeup. They are not able to carry oxygen like the red blood cells, but they defend your body agents various threats. You have different types of white blood cells also called Neutrophil, Eosinophil, Basophil, Lymphocyte, Monocyte, and Macrophage. These white blood cells protect your body in differently from each other. Neutrophils: deal with defense against bacterial or fungal infection and other very small inflammatory processes and are usually first responders to microbial infection. Eosinophils: primarily deal with parasitic infections and an increase in them may indicate such. Basophils: are chiefly responsible for allergic and antigen response by releasing the chemical histamine causing inflammation. Lymphocytes: are much more common in the lymphatic system. The blood has three types of lymphocytes. Monocytes: share the "vacuum cleaner" (phagocytosis) function of neutrophils, but are much longer lived than the neutrophils. Macrophage: are able to develop into the professional phagocytosing macrophage cell after they migrate from the bloodstream into the tissue and undergo differentiation. {BLOOD TRANSFUSION} Blood transfusion is a treatment to replace blood (export and import blood from two or more bodies) of the blood lost through injury and surgery. It is needed if you have had significant blood loss or if your body cannot make or is losing an important amount of blood. A person can donate up to one pint of blood at a time. The donor 2008-01-13T20:43:15-05:00 http://75.150.148.189/free-essay/Essay-on-Blood-33497.aspx Element 112, also called ununbium (Uub), chemical element with atomic number 112. It is produced artificially by nuclear fusion (in which an element with larger atoms is produced by fusing together smaller atoms from other elements). Each ununbium atom has a very large nucleus, or central mass, containing positively charged particles called protons and neutral particles called neutrons. The large number of particles in the nucleus makes the atom unstable and causes the atom to split apart into smaller components soon after it is created. Scientists gave ununbium its temporary name according to a system that uses Latin prefixes for the atomic number (un = 1, un = 1, bi = 2), followed by the suffix -ium or -um. The element will eventually be given a more conventional permanent name by its discoverers. Ununbium was first discovered in 1996 by scientists at the Heavy-Ion Research Laboratory in Darmstadt, Germany. Ununbium has the atomic number 112, which means that each Uub atom contains 112 protons in the nucleus. Scientists at the Heavy-Ion Research Laboratory created an atom of ununbium that contained 165 neutrons, labeled ununbium-277 (112 protons + 165 neutrons = ununbium-277). Ununbium was created by nuclear fusion of the smaller elements lead (Pb) and zinc (Zn). Because the ununbium nucleus contains so many particles, ununbium is unstable and undergoes spontaneous fission, a process in which the atom breaks into smaller œdaughter components. When the atom splits, it releases energy in the form of electromagnetic waves and electrically charged bits of matter. This energy is known as radiation (see Radioactivity). Ununbium-277 has a very brief life span of .00048 seconds. By 1998 ununbium-277 was the only confirmed isotope of Element 112. Other isotopes of element 112 would be forms of the element with the same number of protons in the nucleus, but a different number of neutrons. Ununbium belongs to Group 12 (IIb) on the periodic table, which also contains the naturally occurring elements zinc (Zn), cadmium (Cd), and mercury (Hg) (see Chemical Element). Relative to other metallic elements, zinc, cadmium, and mercury have high boiling points and low melting points. Zinc, cadmium, and mercury are all reactive with oxygen (O), sulfur (S), and the halogens (Group 17 or VIIa). Because elements in the same group, or column, on the periodic table often share similar properties (a pattern known as the periodic law), scientists expect ununbium to share properties with other Group 12 2007-02-22T06:20:59-05:00 http://75.150.148.189/free-essay/Defining-Element-112--32690.aspx Anhydrous Ammonia is a very distinctive and important compound. Some call it a harmless fertilizer which farmers use to help grow and fertilize crops. Other may call it destructive or dangerous to the environment; in other words, a threat. Causing water pollution by toxic fluids running off into coastal waters and into storm drains and air pollution releasing toxins into the air while producing this deadly chemical, anhydrous ammonia been called many things. Anhydrous ammonia is a man-made product used for fertilizer, nitric acid production, refrigeration, disinfectant, fuel and cigarettes. It must be handled carefully by trained professionals and stored in a high-pressured environment using special equipment. Anhydrous Ammonia is also called Ammonia and Ammonium Hydroxide. There are many ways to make Anhydrous Ammonia; one of them being from the urine in our bodies, which is an acid and can be made into any sort of ammonia. It is made by using temperature, pressure and sometimes catalysts. It is one part nitrogen and three parts hydrogen. Anhydrous Ammonia is one of the most dangerous chemicals that can be used on the farm. Anhydrous Ammonia is a low cost and readily available fertilizer, but the danger and consequences are far worse than the lack of it. Ammonia is a colorless, pungent gas, NH3, extensively used to manufacture fertilizers and a wide variety of nitrogen-containing organic and inorganic chemicals. It is the most familiar compound composed of the elements nitrogen and hydrogen. It is formed as a result of the decomposition of most nitrogenous organic material, and its presence is indicated by it pungent and irritating odor. It has a wide range of agricultural and industrial applications. It is used for the production of nitric acid and ammonium salts, particularly the sulfate, nitrate, carbonate, and chloride, and the synthesis of hundreds of organic compounds including many drugs, plastics and dyes. Its dilute liquid solution finds use as a household cleaning tool. Anhydrous ammonia and ammonium salts are used as fertilizers, and anhydrous ammonia also serves as a refrigerant because of its relative ease of liquefaction and high heat of vaporation. Ammonia is highly mobile in the liquid state and has a high thermal coefficient of expansion. The chemical and physical properties of liquid ammonia make it appropriate for use as a solvent in certain types of chemical reactions. Ammonia is generally a better solvent for covalent substances than is water. Its major 2007-02-15T01:24:10-05:00 http://75.150.148.189/free-essay/Anhydrous-Ammonia--32619.aspx Important Information on Titanium Titanium was discovered in 1791 in the mineral menachanite by the British clergyman William Gregor, who named the new element menachite. Four years later, the German chemist Martin Heinruch Klaproth rediscovered the element in the mineral rutile and named it titanium in allusion to the strength of the mythological Greek Titans. The metal was isolated in 1910. The element is present in meteorites and the sun. It is used in many things that enhance everyday life such as fashion apparel, medical equipment, automobiles, architecture, aerospace, marine technology, industrial tools, as well as sports equipment. Titanium has played a main role in helping to not only conserve, but to improve our economy. Because of its strength and light weight, Titanium is used in metallic alloys and as a substitute for aluminum. It is used in aircrafts for the fire walls, outer skin, landing- gear components, hydraulic tubing , and engine supports. Space capsules and missiles are also largely made with titanium , and were used immensely when making the Mercury, Gemini, and Apollo capsules. The relative inertness of titanium makes it available as a replacement for bone and cartilage in surgery and as a pipe and tank lining in the processing of foods that we eat. It is used in heat exchangers in desalinization plants because of its ability to withstand saltwater corrosion. Titanium dioxide, which is commonly known as titanium white, is a brilliant white pigment used in paints, lacquers, paper, plastics, textiles, and rubber. Titanium is the fourth most abundant metals in the earth’s crust. The capacity for production substantially exceeds long term forecast of demand. Product prices are low and stable. Titanium and rutile ore both sourced in friendly countries with stable regimes, unlike nickel or chromium, and so the price of titanium has never really been subject to crisis or political factors. The ready availability of titanium in a wide and ever increasing range of product forms has assured its growth as a basic, general engineering material. Today a network of mills, stockiest, machinists, and fabricators ensure that the demands of design quality and speed of delivery can be met to many businesses around the world. The extraction of titanium is a multi-stage process in that it is the first metallic product being “sponge”. This product has no value as an engineering material, and needs to be consolidated and melted to produce 2007-01-29T05:14:40-05:00 http://75.150.148.189/free-essay/Important-Information-on-Titanium-32477.aspx What do a glittering diamond and a lead pencil have in common? Diamonds are very hard and the graphite of the pencil’s tip is very soft. These two different substances contain a wonderful proof of creation called carbon. A rough, unpolished diamond is the hardest of all minerals.(1) For this reason, a crystal diamond is used to cut and to drill all kinds of material and is also used as an abrasive to smooth surfaces. (2) Hardness is the resistance of a mineral to scratches from outside forces; it is easy to recognize minerals by this trait. By scratching one mineral with another, their relative hardness can be determined. Scientists use a point system to designate the hardness of all minerals. They rate diamonds with the highest ratio of ten over ten. So, what makes diamonds so hard? It is very interesting that the soft, breakable graphite in a pencil tip is made up of the same atoms as a diamond. Graphite is composed of the same carbon atoms as a diamond. But, while one is very soft, the other is extremely hard. One is as black as a lump of charcoal; the other may be sparkling bright. One is commonly found in nature; the other is rare. For all these reasons, diamonds are much more valuable than graphite. How is it then, that carbon atoms can be so different from one another? Carbon: The Foundation of Life (The Value of Diamonds is Determined by its Atoms) Before we consider the differences, we must speak about the carbon atoms that make up a diamond. The carbon atom is very important for living creatures. Nevil Sidgwick, the English chemist, states the following in his book, Chemical Elements and Their Compounds: Carbon is unique among the elements in the number and variety of the compounds which it can form. Over a quarter of a million have already been isolated and described, but this gives a very imperfect idea of its powers, since it is the basis of all forms of living matter. (3) The class of compounds formed exclusively from carbon and hydrogen are called hydrocarbons. This is a huge family of compounds that include natural gas, liquid petroleum, kerosene, and lubricating oils. The hydrocarbons ethylene and propylene form the basis of the petrochemical industry. Hydrocarbons like benzene, toluene, and turpentine are familiar to anyone who has worked with paints. The naphthalene that protects our clothes from moths 2007-01-27T17:18:44-05:00 http://75.150.148.189/free-essay/Diamonds-The-Hardest-of-Minerals-32458.aspx Types of Chemical reactions Lots of reactions take place around us in everyday life. Reactions are quit important in chemistry and in science generally. Chemical reaction is the changing of substances to other substances by the breaking of bonds in reactants and the formation of new bonds in products. There are different types of chemical reaction: 1. Combination 2006-12-05T13:13:09-05:00 http://75.150.148.189/free-essay/Chemical-Reactions--31875.aspx The Properties of Magnesium (Mg) Magnesium, symbol Mg, is a silvery white metallic element that is relatively un-reactive. In group 2 of the periodic table, magnesium is one of the alkaline earth metals. The atomic number of magnesium is 12. Properties and Occurrence The metal, first isolated by the British chemist Sir Humphry Davy in 1808, is obtained today chiefly by electrolysis of fused magnesium chloride. Magnesium is malleable and ductile when heated. With the exception of beryllium, it is the lightest metal that remains stable under ordinary conditions. The metal is not attacked by oxygen, water, or alkalies at room temperature; it reacts with acids. When heated to about 800° C, it reacts with oxygen and emits a brilliant white light. Magnesium melts at about 649° C, boils at about 1107° C, and has a specific gravity of 1.74; the atomic weight of magnesium is 24.305. Magnesium ranks sixth in natural abundance among elements in crustal rocks. It occurs in nature only in chemical combination with other elements, particularly as the minerals carnallite, dolomite, and magnesite; in many rock-forming silicates; and as salts, such as magnesium chloride, in ocean and saline-lake waters. It is an essential part of animal and plant tissue. Uses Magnesium forms compounds, among which are magnesium carbonate (MgCO3), which is formed by the reaction of a magnesium salt and sodium carbonate and is used as a refractory and insulating material; magnesium chloride (MgCl2•6H2O), which is formed by reacting magnesium carbonate or oxide with hydrochloric acid and is used as dressing and filler for cotton and woolen fabrics, in paper manufacture, and in cements and ceramics; magnesium citrate (Mg3(C6H 5O7) 2•4H2O), which is formed by the reaction of magnesium carbonate with citric acid and is used in medicine and effervescent beverages; magnesium hydroxide (Mg(OH) 2), formed by the reacting of magnesium salt and sodium hydroxide and used in medicine as the laxative “milk of magnesia,” and in sugar refining; magnesium sulfate (MgSO4•7H2O), well known as Epsom salt; and magnesium oxide (MgO), called burnt magnesia, or magnesia, prepared by burning magnesium in oxygen or by heating magnesium carbonate and used as a heat-refractory and insulating material, in cosmetics, as a filler in paper manufacture, and as a mild, antacid laxative. Alloyed forms of magnesium have considerable tensile strength. The metal is used when lightness is an essential factor: alloyed with aluminum or copper, it 2006-11-03T01:11:31-04:00 http://75.150.148.189/free-essay/The-Properties-of-Magnesium-Mg-31686.aspx Chemistry Lab: Concentration's effects on Rate of Reaction Aim: The aim of this investigation is to investigate the rate of reaction of magnesium (mg) with Hydrochloric acid (HCl). After studying the availability of equipment I have chosen to investigate how concentration can affect the rate of reaction. Other variables that affect this investigation are: - Concentration of solution - Temperature - Surface area of a solid - Catalyst - Light - Pressure of a gas Prediction: I predict that when changing the concentration of hydrochloric acid and water, the slower the rate of reaction will be. I think this because when observing a previous experiment, it showed the less Hydrochloric acid and the more water used in a test tube, the rate of reaction is slow. Scientific knowledge: To help me gain better knowledge about the investigation I have found out some scientific information relating to the experiment of ‘rates and reaction’. The main areas I have covered are concentration of solution, temperature and catalyst. After researching my scientific evidence I have found out that depending on collisions in particles will depend on the reaction being faster or slower. This happens if the reacting particles collide with each other, or there is sufficient energy in the collision to overcome the activation energy. Concentration To increase the rate of reaction, the concentration of the reaction needs to increase this is by the Hydrogen and magnesium ribbon being added to the solution of Hydrochloric acid. The following reaction occurs: Temperature If temperature is increased the rate of reaction also increase. This is by the chemical particles receiving kinetic energy. If more kinetic energy is present in the particles, the particles move faster, this also means the particles will be colliding with each other often. Catalysts A catalyst is a substance that changes the rate of reaction but remains unchanged itself therefore it is an element that changes the rate of a chemical reaction without being used up. For example, iron speeds up the reaction between nitrogen and hydrogen to make ammonia. Equipment: Test Tube Rack 2 Measuring Cylinders 5 Magnesium Strip Hydrochloric Acid Test Tubes Sand Paper Stop Clock Water Method: 1. Collect all equipment; cut 5 magnesium strips (10cm) the same size. After that, using the sandpaper, sand any Magnesium Oxide layer (rust) off the magnesium strips. 2. Collect the hydrochloric acid and measure out 2006-08-07T15:26:34-04:00 http://75.150.148.189/free-essay/Chemistry-Lab-Concentration-s-effects-on-Rate-of-Reaction-31133.aspx Brief Explanation of Titration Titration is the addition of an acidic solution to a basic solution or when you add a basic solution to an acidic solution. Titrations are used to determine the concentration of acids or bases in solution. An example of a titration is when a given volume of a solution of unknown acidity may be titrated with a base of known concentration until complete neutralization has occurred. This point is called the equivalence point and is generally determined by observing a color change in an indicator. From the volume and concentration of 2006-07-29T16:25:29-04:00 http://75.150.148.189/free-essay/Brief-Explanation-of-Titration-30794.aspx Analysis of the Chemistry of Artificial Sweetener Chemists have been looking for a sweetener that is sweet or sweeter than sucrose. They want it to have a pleasant taste with no aftertaste, is nontoxic, inexpensive, easy to make, stable to heat, stable in light, dissolves Readily in water, 2006-07-05T23:23:58-04:00 http://75.150.148.189/free-essay/Analysis-of-the-Chemistry-of-Artificial-Sweetener-30046.aspx Analysis of the Practice of Combinatorial Chemistry This article mainly talks about how combinatorial synthesis or chemistry is being used in the drug industry today. The article starts with how combinatorial synthesis began. It said it started in the early 1990s as an ambition of revolutionizing drug discovery. The rest of the article mainly talks about how they screen for highly complex mixtures, mixtures of equivocal mixtures. Then they move on to talk about screening of the interior of resin beads and then the screening of mircoarrays. This article says that if bridging the gap between combinatorial synthesis and bioassays is important if combinatorial chemistry is to achieve is ambitious goal of supplying efficient methods for the selection of biologically active molecules.”(Direct from article). This article had some good and some bad points throughout it. The main problem with the article is that it was really hard to understand. They used a lot of terms that as the reader, I would not know. This article also seemed very technical, saying that this, this and this did this. Not much was on what is combinatorial synthesis. This article was probably intended for those who know about this stuff already. But why then start with something that would sound like some who has never know about this before what to find out more about it. This article was brief too; it sped through things really quick and ended pretty quickly too. It should have flowed so the reader could read it more easily. Fairley, Peter. (1998). Combinatorial Chemistry. Chemical Week, 150, 18 In the article Combinatorial Chemistry they basically talk about what it is. The article says that it is a “the rapid synthesis of thousands or millions of chemical com-pounds.” It says that combinatorial chemistry has revolutionized the drug industry discovery process. The company R&D wonders what this experimentation could do for their product research. It provides many uses for combinatorial chemistry in research and the development of combinatorial chemistry in the chemical industry. There is one question that arises with combinatorial chemistry, which is whether this rapid screening can detect qualities of interest to industry researchers. But skepticism is fading rapidly with the recent research that they have found from companies like R&D, and by academic researchers. 2006-07-05T22:45:13-04:00 http://75.150.148.189/free-essay/Analysis-of-the-Practice-of-Combinatorial-Chemistry-30034.aspx ENZYME INVESTIGATION Planning Introduction: An Enzyme is any one of many specialised organic substances, composed of polymers of amino acids, that act as catalysts to regulate the speed of the many chemical reactions involved in the metabolism of living organisms. Those enzymes identified now number more than 700. Enzymes are classified into several broad categories, such as hydrolytic, oxidising, and reducing, depending on the type of reaction they control. Hydrolytic enzymes accelerate reactions in which a substance is broken down into simpler compounds through reaction with water molecules. Oxidising enzymes, known as oxidises, accelerate oxidation reactions; reducing enzymes speed up reduction reactions, in which oxygen is removed. Many other enzymes catalyse other types of reactions. Individual enzymes are named by adding ASE to the name of the substrate with which they react. The enzyme that controls urea decomposition is called urease; those that control protein hydrolyses are known as proteinases. Some enzymes, such as the proteinases trypsin and pepsin, retain the names used before this nomenclature was adopted. Structure and Function of an Enzyme Enzymes are large proteins that speed up chemical reactions. In their globular structure, one or more polypeptide chains twist and fold, bringing together a small number of amino acids to form the active site, or the location on the enzyme where the substrate binds and the reaction takes place. Enzyme and substrate fail to bind if their shapes do not match exactly. This ensures that the enzyme does not participate in the wrong reaction. The enzyme itself is unaffected by the reaction. When the products have been released, the enzyme is ready to bind with a new substrate. Properties of Enzymes As the Swedish chemist Jöns Jakob Berzelius suggested in 1823, enzymes are typical catalysts: they are capable of increasing the rate of reaction without being consumed in the process. Some enzymes, such as pepsin and trypsin, which bring about the digestion of meat, control many different reactions, whereas others, such as urease, are extremely specific and may accelerate only one reaction. Still others release energy to make the heart beat and the lungs expand and contract. Many facilitate the conversion of sugar and foods into the various substances the body requires for tissue-building, the replacement of blood cells, and the release of chemical energy to move muscles. Pepsin, trypsin, and some other enzymes possess, in addition, the peculiar property known as autocatalysis, which permits them to cause their own formation from an inert 2006-07-05T15:19:16-04:00 http://75.150.148.189/free-essay/Enzyme-investigation--30009.aspx Summary of the Peridoic Table of Elements In the early 1800s, many attempts were made to organize the arrangement of the 2006-06-22T14:27:16-04:00 http://75.150.148.189/free-essay/Summary-of-the-Peridoic-Table-of-Elements-29801.aspx Introduction Aspirin was the first drug to come in common usage and it is still widely used in the world. It is a pain-reliever that reduces fewer and is an inhibitor of platelet aggregation. It is an ingredient in a large pain-relieving and cold/flu preparations. Nowadays doctors often prescribe it as a valuable medicine to prevent heart attacks and it is under examination for other medical conditions such as cancer and diabetes. Aspirin was origined from a willow tree (herbal tree) in olden days. In Greece Hippocrates leaves from the willow tree was used to make a tea that relieves the pain of childbirth for women. In 1763 Reverend Edward Stone of Oxford gave dried bark of the willow tree to 50 parishioners suffering rheumatic fever. In Italy (1823) the main ingredient was extracted from the willow tree and named salicin. Salicin was also found in the meadowsweet flowers by the Swiss and German researchers. In Germany (1897), Bayer's Felix Hoffmann got an approval for a trademark and develops a process for synthesizing acetyl salicylic acid or Aspirin and the clinical trial begins. In 1899 clinical trial are successfully completed and for the first time Aspirin was launched. Chemical Process As the active ingredient in aspirin, acetylsalicylic acid works by going through several different chemical processes within the body, including the natural physiological processes causing pain and inflammation. Aspirin is known as ‘acetylsalicylic acid’ and has a chemical formula of C9H8O4. It inhibits enzyme converting acid to prostaglandin. Aspirin is pain-relieving, anti-inflammatory, a drug that reduces fewer and is an inhibitor of platelet aggregation. Preparation of aspirin Aspirin is prepared by the synthesis from acetylic acid. Nowadays doctors use aspirin in small daily doses to prevent diseases such as heart attack, stroke and the blindness and kidney damage suffered by many patients with diabetes. If Aspirin is dissolved in water the solution will be acidic (just like vinegar and lemon juice are acidic). Aspirin is a weak acid, so basically unless lot of aspirin is dissolved in water it will not be nearly as strong as an acid. The formula of aspirin C9H8O4 tells you how many atoms are in each molecule of salicylic acid. So there are 9C (carbon) atoms, 8H (hydrogen) atoms and 4O (oxygen) atoms. These atoms are ordered (arranged) in a very cool manner. Six 2006-06-13T02:25:16-04:00 http://75.150.148.189/free-essay/Chemistry-of-Aspirin--29391.aspx A Study of the Battery In this highly technological world with advanced machines, electronics have been woven into almost every aspect of everyday life. Batteries are integrated into the majority of any electric appliance found in the home and work place, and therefore could be titled as one of the most important tools to ever be invented. The knowledge of how batteries operate is substantial to understanding the basics of any electrical contraption. The first evidence of batteries was dated to be from in the neighborhood of 250B.C. These ancient batteries were discovered in archaelogical digs in Baghdad, Iraq. These antiquated batteries were used in simple operations to electroplate objects with a thin layer of metal, much the same way we plate things with gold and silver. Much later, batteries were re-discovered in 1800 by a man named Alessandro Volta. The electrical unit of potential was named after him-the volt. Alessandro Volta was born in 1745 and died in 1827, and in this time period he re-produced one of the most important parts of life. He developed the battery by alternating pieces of electrolyte soaked discs (sodium chloride), zinc, and copper plates. These plates and discs were stacked in a 1 2 3 order, and when a wire was placed on the two poles of the battery it would produce electricity. Battery chemistry is a complex science to gain complete knowledge about, but basic battery chemistry will be covered. “An electrochemical cell uses energy released from a spontaneous chemical redox reaction to generate electric current. The current is derived from the flow of electrons conducted through the metal and the movement of ions in a solution, called electrolytic conduction. A battery consists of a single electrochemical cell or a number of cells connected in series.”(Fisher,518) A battery could be created by using a Zinc anode and a copper cathode. An anode is a part of an electrochemical cell that releases electrons to the cathode, therefore being oxidized, and a cathode receives the electrons from the anode, therefore it undergoes reduction. So to create the Zinc/Copper battery, the Zinc rod would be placed into a Zinc Sulphate solution(ZnSO4), and the Copper rod would go into the Copper Sulphate solution(CuSO4). When the two rods are connects in some way, by wire or by deliberate touch, many things happen. 2006-06-12T19:04:16-04:00 http://75.150.148.189/free-essay/A-Study-of-the-Battery-29356.aspx Analysis of the Element Lithium Lithium, which is represented by the symbolic notation, Li, is the third element on the periodic table. The mineral Petalite (which contains lithium) was discovered by the Brazilian scientist José Bonifácio de Andrada e Silva towards the end of the 18th century while visiting Sweden. Lithium was discovered by Johan August Arfvedson in 1817 during an analysis of Petalite ore. Arfvedson subsequently discovered lithium in the minerals spodumene and lepidolite. C.G. Gmelin observed in 1818 that lithium salts color flames were bright red. Neither Gmelin nor Arfvedson were able to isolate the element itself from lithium salts, for example in attempted reductions by heating the oxide with iron or carbon. The first isolation of elemental lithium was achieved later by W.T. Brande and Sir Humphrey Davy by the electrolysis of lithium oxide. In 1855, Bunsen and Mattiessen isolated larger quantities of the metal by electrolysis of lithium chloride. In 1923 the first commercial production of lithium metal was achieved by Metallgesellschaft AG in Germany using the electrolysis of a molten mixture of lithium chloride and potassium chloride. Lithium’s origin name was founded from the Greek word “lithos” meaning “stone”, apparently because it was discovered from a mineral source. William Thomas Brande and Sir Humphrey Davy first isolated the element through the electrolysis of lithium chloride oxide. In 1855, Bunsen and Mattiessen isolated larger qualities of the metal by electrolysis of lithium chloride. Lithium is widely distributed in nature, in soil, plants, animals and even the human body. However, it is also located on the earth’s outermost layer, but makes up only .00007% of the earth’s crust. Lithium is a Group 1 (IA) element containing just a single valence electron. Group 1 elements are called "alkali metals". Lithium is a soft, white solid metal that is about half as dense as water. A freshly cut chunk of lithium is silvery, but tarnishes in a minute or so in air to give a grey surface effect. Many uses have been found for lithium metals and its compounds. Lithium has the highest specific heat of any solid element and is used in heat transfers and various nuclear applications. It is also used in the production of special glasses and ceramics pieces. Lithium is the lightest known metal and can be alloyed with aluminum, copper, manganese, and cadmium to make strong, lightweight metals 2006-06-11T18:49:02-04:00 http://75.150.148.189/free-essay/Analysis-of-the-Element-Lithium-29195.aspx Analysis of the metal silver's chemistry Hello my fellow readers. My name is Silver. My name comes from the Anglo-Saxon word of Siolfur. Some people call me Ag for short (Ag stands argentum.) I am a white shinny metal. Since I am a white shinny metal argentum is the Latin word for white and shinning. I live in the periodic table of elements and my address is 47. I usually weigh 107.868. I am solid at room temperature. Copper and gold are my good friends and they make me strong and help me to be more durable. You can find me almost anywhere. You can find me pure in silver ores and you can find me in structure forms in kitchens, jewelry stores, car shops, doctor offices, dentist offices, banks, and even in wallets. I am a very valuable metal. But although you can find me most anywhere, only 16% of me is used in coins and jewelry, while 40% is used to make photographic film. The rest of me is used in industries and health services. I am even used to make mirrors. I am only slightly reactive and because of this I am placed very close to the bottom of the reactivity chart. I have very little uses in chemistry because of my low reactivity status. I don’t form oxides when I touch air but I do form silver sulfide when I touch polluted air. I form a tarnish when I interact with the hydrogen sulfide in the air, especially near industrial cities. The result of this is that I turn to silver sulfide. Tarnish is a dark, brown, or black film that develops slowly on me. Some silver tableware can tarnish because some food that you eat contains hydrogen sulfide. Hard boiled eggs are the perfect example of hydrogen sulfide. You can also sometimes see it in the dark ring around the yolk. Sterling and I are used to make jewelry, cutlery and serving dishes. They are made of 92.5% of me and 7.5% of copper. Copper makes me harder, stronger, and more durable. I lie between gold and copper as one of the softest metals. I’m the best conductor of heat and electricity. My friends, gold, platinum, mercury, and I make up the noble metals. We don’t oxidize readily when heated and we don’t dissolve in most mineral acids. I am a rare element because I’m the 68th in the elements 2006-06-07T16:25:14-04:00 http://75.150.148.189/free-essay/Analysis-of-the-Metal-Silver-s-Chemistry-29100.aspx Laboratory Analysis on Strength of Aluminum and Steel Summary: Aluminum and steel were tested over three different temperature readings. One of each sample was put into an oven at about 245°F, a bath of ice water and finally in dry ice at about -30°F. After the metal sample’s temperature was changed by exposure to each external stimulus, we proceeded to break each sample. The Impact Test Machine was used to break the steel sample. The CIM-24 was used to break the aluminum sample. Procedure: The pendulum was raised up to the top position just prior to doing the test. After the sample was exposed to the different stimulus for about 15 minutes, the samples were placed into the machine. 2006-05-31T23:44:01-04:00 http://75.150.148.189/free-essay/Laboratory-Analysis-on-Strength-of-Aluminum-and-Steel-28948.aspx Applications of Silicon Silicon is one of man’s most useful elements. In the form of sand and clay it is used to make concrete and brick; it is a useful refractory material for high-temperature work, and in the form of silicates it is used in making enamels, pottery, etc. Silica, as sand, is a principal ingredient of glass, one of the most inexpensive of materials with excellent mechanical, optical, thermal and electrical properties. Hyperpure silicon can be doped with boron, gallium, phosphorus, or arsenic to produce silicon for use in transistors, solar cells, rectifiers, and other solid-state devices, which are used extensively in the electronics and space-age industries. Though silicon was originally discovered in 1810 and thought to be a compound silicon was discovered as an element in 1823 by Jons Berzelius. In 1824 Berzelius prepared amorphous silicon by the same general method and purified the product by removing the fluosilicates by repeated washings. Deville in 1854 first prepared crystalline silicon, the second allotropic form of the element. Davy in1800 thought silica to be a compound and not an element; later in 1811, Gay Lussac and Thenard probably prepared impure amorphous silicon by heating potassium with silicon tetrafluoride. Silicon is a metalloid at room temperature with an atomic number of 14, 14 electrons, 14 neutrons, and an average atomic mass of 28.0855. In its pure form,silicon melts at 2,570 degrees, and boils at 4,271 degrees Fahrenheit. This element belongs to the metalloid family, the 14th family on the periodic table of elements. This element is a solid metalloid at room temperature and turns to liquid at 2,570 degrees. Silicon is prepared as a brown amorphous powder or as gray-black crystals. Crystalline silicon has a metallic luster and grayish color. It is hard, non-magnetic, and most acids do not effect it, but it does dissolve in hydrofluoric acid, forming the gas, silicon tetrafluoride, SiF 4. At ordinary temperatures silicon is impervious to air, but at high temperatures it reacts with oxygen, forming a layer of silica that does not react further. At high temperatures it also reacts with nitrogen and chlorine to form silicon nitride and silicon chloride, respectively. Elemental silicon transmits more than 95% of all wavelengths of infrared, from 1.3 to 6.y micro-m. Silicon is present in the soil and makes up about 25.7% of the earth’s crust. Silicon also promotes firmness and strength in human tissues. It is 2006-04-15T05:07:39-04:00 http://75.150.148.189/free-essay/Applications-of-Silicon--28707.aspx Aluminum, symbol Al, the most abundant metallic element in the earth\'s crust. The atomic number of aluminum is 13; the element is in group 13 (IIIa) of the periodic table. Hans Christian Orstead, Danish chemist, first isolated aluminum in 1825, using a chemical process involving potassium amalgam. Between 1827 and 1845, Friedrich Wöhler, a German chemist, improved Oersted\'s process by using metallic potassium. He was the first to measure the specific gravity of aluminum and show its lightness. In 1854 Henri Sainte-Claire Deville, in France, obtained the metal by reducing aluminum chloride with sodium. Aided by the financial backing of Napoleon III, Deville established a large-scale experimental plant and displayed pure aluminum at the Paris Exposition of 1855. Aluminum is a lightweight, silvery metal. The atomic weight of aluminum is 26.9815; the element melts at 660° C (1220° F), boils at 2467° C (4473° F), and has a specific gravity of 2.7. Aluminum is a strongly electropositive metal and extremely reactive. In contact with air, aluminum rapidly becomes covered with a tough, transparent layer of aluminum oxide that resists further corrosive action. For this reason, materials made of aluminum do not tarnish or rust. The metal reduces many other metallic compounds to their base metals. For example, when thermite (a mixture of powdered iron oxide and aluminum) is heated, the aluminum rapidly removes the oxygen from the iron; the heat of the reaction is sufficient to melt the iron. This phenomenon is used in the thermite process for welding iron . The oxide of aluminum is amphoteric—showing both acidic and basic properties. The most important compounds include the oxide, hydroxide, sulfate, and mixed sulfate compounds. Anhydrous aluminum chloride is important in the oil and synthetic-chemical industries. Many gemstones—ruby and sapphire, for example—consist mainly of crystalline aluminum oxide. Aluminum is the most abundant metallic constituent in the crust of the earth; only the nonmetals oxygen and silicon are more abundant. Aluminum is never found as a free metal; commonly as aluminum silicate or as a silicate of aluminum mixed with other metals such as sodium, potassium, iron, calcium, and magnesium. These silicates are not useful ores, for it is chemically difficult, and therefore an expensive process, to extract aluminum from them. bauxite an impure hydrated aluminum oxide, is the commercial source of aluminum and its compounds. In 1886 Charles Martin Hall in the United States and Paul L. T. Héroult in 2006-04-15T04:42:47-04:00 http://75.150.148.189/free-essay/Aluminum-Essay--28699.aspx Murder Mystery - Using Forensics A decent amount of murderers always leave behind clues for the FBI to allow them to figure out who was the culprit in the crime. One really big clue is DNA or blood on the crime scene. In our chemistry mystery, our murderer slips some sodium solfide into a mixed drink, then finishes him with a pistol, but the evidence remains on the scene and it is blood. Blood is something that every living Human Being has. Human red blood cells may contain one or both or neither of 2 antigens, named A or B. Your blood therefore is one of four types: A, B, AB or O, which means it contains neither A or B antigen. Blood type AB is the most rare therefore finding that type at a crime scene narrows down the possibilities. The opposite of that is finding type O bloods, for it is the most common and would have a wide variety of suspects. There is also a thing that is called genetic markers. Genetic Markers function the same for every human being. There are so many genetic markers that finding 3 or 4 same markers in a human being is enough to pick him out of 1 million people. So if they have the same blood type and 3 or 4 genetic markers, it is pretty clear to have them as a top prospect. But once the blood is outside the body, the enzymes deteriorate. By the time that a bloodstain dries, some of the genetic markers are already gone. Since everyone blood type is kept on record, they can just look you up on a computer to see if you are a suspect or not. Another tactic to catch the criminal and plays a big part is called blood splattering. By observing the size, shape, distribution, location, angle of impact, and the surface it was found on, can tell you a whole a lot about the crime. This also means that if a blood splatter was found on someone it means that they were at the scene when the crime happened. Blood splattering can also tell how many times that a victim was hit, it sometimes can leave a cast off stain, which is just like when the blood on the knife, flies off during 2005-12-27T01:46:08-05:00 http://75.150.148.189/free-essay/Murder-Mystery-Using-Forensics-28267.aspx Electron Orbitals The periodic table is simply the organization and classification of different elements. By the end of the 1700’s, scientists had identified about 30 elements. In less than 100 years, the number of known element doubled because of new means of recognizing them. In the early 1800’s, Dobereiner observed that there were elements that could be classified into groups of 3, or triads. These triads were significant because these classifications of similar elements represented the very beginning of the periodic table. The triads related atomic mass (in amu) to density. In 1865 a chemist named Newlands presented another way of classifying elements. In his time 62 elements were know. Newlands organized the elements in order of increasing atomic mass, and noticed that the properties of the first element were the similar to the eighth, the second to the ninth, and so on. He named this the law of octaves, as there are 8 notes in the musical scale. (octave to octave) The man most famous in relation to the periodic table, Dmitri Mendeleev, along with Lothar Meyer published tables almost identical of those to Newlands. Mendeleev organized the elements in such a way as to make it easier for his students to understand. He eventually made the first actual periodic table of elements. This table had elements with similar properties in the same column. Mendeleev’s table was so well designed and so accurate, that he was able to predict elements that had yet to be discovered with much precision. In 1913, Mosely discovered the concept of the atomic number. Even though Mendeleev’s table was arranged by atomic mass, and now the periodic table is arranged by atomic number, why is Mendeleev’s table valued so highly? The first table is so important because the general rule is that as the atomic mass increases, so does the atomic number. Even though Mendeleev was organizing the elements the “wrong way”, his table is still incredibly similar to the present one. The periodic law is the basis for the periodic table. The periodic law states the following: When elements are arranged in order of increasing atomic number, their physical and chemical properties show a periodic pattern. The modern periodic table has one hundred and nine squares, each representing a unique element. Above the abbreviation of the element 2005-09-14T00:09:27-04:00 http://75.150.148.189/free-essay/Electron-Orbitals--27965.aspx Sodium Sodium is an element found in the forest in its natural form. The atomic has and atomic number is 11 so it means it has 11 protons and 11 electrons. The Elements can be used in many formulas to make a compound. Its atomic number is 22.989770.The elements boiling point is 883 degrees Celsius. The melting point is 98 degrees Celsius. 2005-09-07T02:34:29-04:00 http://75.150.148.189/free-essay/Sodium--27937.aspx Discovery of Polyurethane Originally two German chemists named Wurtz, in 1848, and Hentschel, in 1884 made the first Isocyanates, one of the building blocks of Polyurethane. Originally polyurethane was developed for military use by Otto Bayer, in the late 1930's, and was the first to make polyurethane commercially available. Molecular Structure Polyurethane is a polymer that consists of repeating units [__ROOCNH__R'__]n. 'R' can represent a different alkyl group, which is obtained by removing a hydrogen atom from a hydrocarbon. Polyurethane's are mostly thermoset plastics meaning the resins cross-link and cannot be melted and remolded. Some polyurethane's are Linear Aliphatic Polyurethane which are thermoplastics. This means the resins are linear and do not cross-link, subsequently they can be reprocessed. Thermoplastic polyurethane is not only linear but has highly crystalline structures. It is because of this that it forms an abrasion resistant material. The diagram above shows the molecular structure of complex polyurethane. Complex polyurethane is considered this because it is made from an isocyanate base. This type of urethane is created through the reaction between an isocyanate and a polyol (Alcohol). Types There are many different types of polyurethane’s to include the following: rigid foams, flexible foams, adhesives, sealants, coatings, cast elastomers, and spandex fibers. All polyurethane’s have one thing in common: they contain urethane linkages formed by the chemical reaction between the isocyanate and the polyol. These various forms make polyurethane a very versatile plastic in liquid and solid form. Applications Rigid foams or hard foams are used as insulation for buildings, water heaters, refrigeration, and floatation devices. Flexible foams or soft, open-celled polyurethane foams are used as cushion padding under carpets, furniture cushioning, mattresses, and packaging material. Adhesives and sealants are used where high strength, moisture resistance and durability is needed such as construction, automotive and marine applications. Mainly in the automotive field you will see polyurethane as the paint or clear coat on your car, and the glue used to assemble items in your vehicle, and the soft cushions that make up your seat backs and bottoms you sit on. Some foams are also used as the soft cushioning on your dashboard, headliner, steering wheel, and gearshift handles. Most urethanes used in the automotive field are paints and coatings, as well as, foam rubbers. Thermoplastic elastomers 2005-09-03T05:43:08-04:00 http://75.150.148.189/free-essay/Discovery-of-Polyurethane-27871.aspx Nitrogen was isolated by the British physician Daniel Rutherford in 1772 and recognized as an elemental gas by the French chemist Antoine Laurent Lavoisier about 1776. Properties Nitrogen is a colorless, odorless, tasteless, nontoxic gas. It can be condensed into a colorless liquid, which can in turn be compressed into a colorless, crystalline solid. Nitrogen exists in two natural forms of isotopes, and four radioactive isotopes have been artificially prepared. Nitrogen melts at -210.01° C (-346.02° F), boils at -195.79° C (-320.42° F), and has a density of 1.251 g/liter at 0° C (32° F). The atomic weight of nitrogen is 14.007. Nitrogen is obtained from the atmosphere by passing air over heated copper or iron. The oxygen is removed from the air, leaving nitrogen mixed with some inert gases. Pure nitrogen is obtained by partial evaporation of liquid air because liquid nitrogen has a lower boiling point than liquid oxygen, the nitrogen evaporates off first and can be collected. Nitrogen composes about four-fifths (78.03 percent) by volume of the atmosphere. Nitrogen is inert and serves as a diluent for oxygen in burning and respiration processes. It is an important element in plant nutrition certain bacteria in the soil convert nitrogen from the atmosphere into a form, such as nitrate, that can be absorbed by plants, a process called nitrogen fixation. Nitrogen in the form of protein is an important component of animal tissue. The element occurs in the combined state in minerals, of which saltpeter (KNO3) and Chile saltpeter (NaNO3) are highly important products. Nitrogen combines with other elements only at very high temperatures or pressures. It is converted to an active form by passing through an electric discharge at low pressure. The nitrogen produced is very active, combining with alkali metals to form azides with the vapor of zinc, mercury cadmium, and arsenic to form nitrides and with many hydrocarbons to form nitriles. Activated nitrogen returns to ordinary nitrogen in about one minute.In the combined state nitrogen takes has many reactions it forms so many compounds that a systematic scheme of compounds containing nitrogen in place of oxygen was created by the American chemist Edward Franklin. In compounds nitrogen exists in all the combination capacity states between -3 and +5. Ammonia, and hydroxylamine represent compounds in which the combination capacity of nitrogen is -3, -2, and -1, individually. Oxides of nitrogen represent nitrogen in all the positive combination capacity states. Uses Most of 2005-08-26T10:52:46-04:00 http://75.150.148.189/free-essay/Properties-and-History-of-Chemical-Element-Nitrogen-27792.aspx How Solar Cells Generate Energy Solar cells today are mostly made of silicon, one of the most common elements on Earth. The crystalline silicon solar cell was one of the first types to be developed and it is still the most common type in use today. They do not pollute the atmosphere and they leave behind no harmful waste products. Photovoltaic cells work effectively even in cloudy weather and unlike solar heaters, are more efficient at low temperatures. They do their job silently and there are no moving parts to wear out. It is no wonder that one marvels on how such a device would function. To understand how a solar cell works, it is necessary to go back to some basic atomic concepts. In the simplest model of the atom, electrons orbit a central nucleus, composed of protons and neutrons. each electron carries one negative charge and each proton one positive charge. Neutrons carry no charge. Every atom has the same number of electrons as there are protons, so, on the whole, it is electrically neutral. The electrons have discrete kinetic energy levels, which increase with the orbital radius. When atoms bond together to form a solid, the electron energy levels merge into bands. In electrical conductors, these bands are continuous but in insulators and semiconductors there is an "energy gap", in which no electron orbits can exist, between the inner valence band and outer conduction band [Book 1]. Valence electrons help to bind together the atoms in a solid by orbiting 2 adjacent nucleii, while conduction electrons, being less closely bound to the nucleii, are free to move in response to an applied voltage or electric field. The fewer conduction electrons there are, the higher the electrical resistivity of the material. In semiconductors, the materials from which solar sells are made, the energy gap Eg is fairly small. Because of this, electrons in the valence band can easily be made to jump to the conduction band by the injection of energy, either in the form of heat or light [Book 4]. This explains why the high resistivity of semiconductors decreases as the temperature is raised or the material illuminated. The excitation of valence electrons to the conduction band is best accomplished when the semiconductor is in the crystalline state, i.e. when the atoms are arranged in a precise geometrical formation or "lattice". At room temperature and low illumination, pure or so-called "intrinsic" 2005-08-15T08:49:17-04:00 http://75.150.148.189/free-essay/How-Solar-Cells-Work,-Photovoltaic-Cell-Energy-Generation-27682.aspx What are Polymers? How are they different from Monomers? Polymers are large molecules composed of smaller molecules called monomers. Monomers are produced and either grow together or are assembled to produce a single polymer. There are synthetic and natural polymers. Some examples of natural polymers would be wood, starches, fingernails, and hair. Synthetic polymers are usually referred to as plastics. Petroleum, is the primary monomer used to produce polymers. An English chemist named Alexander Parkes was the first scientist to produce the first synthetic polymer in 1862. John Wesley Hyatt, an American, was the first person to produce a useable polymer two years later. He named the product celluloid. The prime virtue of polymers is a high strength-to-weight ratio. Industrial-strength polymers surpass titanium in tensile strength. To add strength and improve flexibility, polymers are sometimes fortified with short-fiber additives, mostly fiberglass. This is known as a polymer composite. One particular polymer has three times the strength of tempered steel and is being used in bullet proof vests. Another composite will be used to fasten together the sections proposed space stations. Polymers have also been used in cars, including the Chevrolet Camaro and the Pontiac Fiero. New polymers are being created with more strength and flexibility by combing two chemically different polymers and producing a block copolymer. Combinations of block copolymers and composites and intended for use in booster rockets and in materials of Earth-orbiting installations. Most common polymers are usually solid, but a new class of polymers is being introduced in a liquid crystal state. Although these polymers still have the physical characteristics of liquid, they are structured more like solids. Many liquid crystals are transparent at one temperature and colored at another temperature. This makes them suitable for use in liquid crystal displays, such as in digital watches, hand-held calculators, and lap-top computers. A new liquid polymer, consisting of a mixture of iron and nickel, is being used to make metal links that can be used in paper, glass, and on electronic circuit boards. Despite the development and widespread use of polymers, scientific understanding is still sketchy. Polymer development has occurred through trial and error. Scientific shortcomings are becoming more apparent in the search for polymers that can meet the demands for high technology of today. The new study is on the microstructure of polymers while still in a liquid state. The purpose is to learn how the solid-state structure is developed. The 2005-08-15T08:32:31-04:00 http://75.150.148.189/free-essay/Polymers-and-their-difference-from-monomers-27668.aspx What is Uranium and what are its uses? Research Paper on an Element Uranium is a silvery-white element possessing a very radioactive and oxidizing character. Uranium retains a density of 19.07 grams per cubic centimeter and a melting point of roughly 1,132 degrees centigrade. With a boiling point of approximately 3,818 degrees Celsius uranium is not an easy element to get to a melting or boiling point. The Periodic Table says that uranium has 92 protons and 146 neutrons thereby acquiring a atomic weight of 238 atomic mass units. Uranium burns readily in air at 150 to 175 degrees centigrade and at 1,000 degrees Celsius uranium combines with nitrogen to form a yellow nitride. Uranium is found in such ores as pitchblende and carnotite. In the crust of the Earth uranium is found at about 2 parts per million. In other words, for every half million tons of nature one digs up, they can expect to find one ton of uranium. To mine this element, miners will break up and mix pitchblende with sulfuric and nitric acids. This then breaks the uranium into uranyl sulfate and with the addition of heat, uranium is then precipitated as sodium diuranate and collected. Humans today use uranium to produce nuclear weapons and nuclear reactors. While producing electrical energy, power plants consume close to 40 million tons of coal per month, while the same output could be obtained by using only 15 pounds of uranium per month! Summary: *Uranium is a very heavy (dense) metal which can be used as an abundant source of concentrated energy. *It occurs in most rocks in concentrations of 2 to 4 parts per million and is as common in the earth's crust as tin, tungsten and molybdenum. It occurs in seawater, and could be recovered from the oceans if prices rose significantly. *It was discovered in 1789 by Martin Klaproth, a German chemist, in the mineral called pitchblende. It was named after the planet Uranus, which had been discovered eight years earlier. *Uranium was apparently formed in super novae about 6.6 billion years ago. While it is not common in the solar system, today its radioactive decay provides the main source of heat inside the earth, causing convection and continental drift. *The high density of uranium means that it also finds uses in the keels of yachts and as counterweights for aircraft control surfaces (rudders and elevators), as well as for radiation shielding. *Its melting point 2005-08-15T08:30:26-04:00 http://75.150.148.189/free-essay/What-is-Uranium-and-what-are-its-uses-Research-Paper-27667.aspx How Ethanol is Produced Introduction Ethanol is a colorless volatile flammable liquid C2H5OH that is the intoxicating agent in liquors and is also used as a solvent called ethyl alcohol or grain alcohol (Meriam 1). C2H5OH is the chemistry components of ethanol; this means ethanol is made of Carbon, Hydrogen, and Hydroxide. Starch or sugar-based feedstock, such as corn, have been used to produce ethanol and ethyl alcohol since the beginning ventures into value-added processing (How Ethanol 1). The value-added process means value is added to producing corn because we now have more valuable uses for the grain. Since natural resources are limited, ethanol provides us with an alternate fuel source. The basic steps to produce ethanol have been refined in the past years, which has lead to a highly efficient process (How Ethanol 1). This analysis explains the steps in producing ethanol from corn. The steps for producing ethanol are steeping the corn, which involves grinding and/or soaking, and then cooking, fermenting, and distilling the corn. Dry and Wet Milling are the two different ways ethanol can be produced (How Ethanol 1). The initial grain treatment is the major difference between these two processes (How Ethanol 1). In the Dry Mill process, the corn is put through a grinder, cookers, fermenter, distillation columns, and a molecular sieve. In the Wet Mill process, the corn is steeped, put through a starch/gluten separator, and then the starch is fermentated, (refer to the image for dry milling process). The Process Dry Mill Ethanol Production According to the RFA, grinding the complete corn kernel or other starchy grain produces flour, also known as meal. The meal is then processed without separating the different component parts of the grain. Water is mixed with the meal to form a mash to which enzymes are added to convert the mash starch into sugar. Ammonia is also combined to the mash to activate the yeast and control pH balance. The mash is then put in a high temperature cooker to help keep the bacteria level low before fermentation. The mash is cooled and moved to the fermenters where the addition of yeast produces ethanol and carbon dioxide from the sugar. During the forty or fifty hour fermentation process, the mash is agitated and kept cool to help the yeast activation. 2005-07-29T07:04:50-04:00 http://75.150.148.189/free-essay/How-Ethanol-is-Produced--27444.aspx Helium Chemistry Research Paper Helium (Greek helios,"sun"), symbol He, inert, colorless, odorless gas element. In group 18 of the periodic table, helium is one of the noble gases. The atomic number of helium is 2. Pierre Janssen discovered helium in the spectrum of the corona of the sun during an eclipse in 1868. Shortly after it was identified as an element and named by the chemist Sir Edward Frankland and the British astronomer Sir Joseph Norman Lockyer. The gas was first isolated from terrestrial sources in 1895 by the British chemist Sir William Ramsay, who discovered it in cleveite. In 1907 Sir Ernest Rutherford showed that alpha particles are the nuclei of helium atoms. II PROPERTIES AND OCCURRENCE Helium has monatomic molecules, and is the lightest of all gases except hydrogen. Helium solidifies at -272.2° C; helium boils at -268.9° C. The atomic weight of helium is 4.0026. Helium, like the other noble gases, is chemically inert. Its single electron shell is filled, making possible reactions with other elements extremely difficult and the resulting compounds quite unstable. Molecules of compounds with neon, another noble gas, and with hydrogen have been detected. Helium is the most difficult of all gases to liquefy and is impossible to solidify at atmospheric pressure. These properties make liquid helium extremely useful as a refrigerant and for experimental work in producing and measuring temperatures close to absolute zero. Liquid helium can be cooled almost to absolute zero at normal pressure by rapid removal of the vapor above the liquid. At a temperature slightly above absolute zero, it is transformed into helium II, also called superfluid helium, a liquid with unique physical properties. It has no freezing point, and its viscosity is apparently zero; it passes readily through minute cracks. Helium-3, the lighter helium isotope, which has an even lower boiling point than ordinary helium, exhibits different properties when liquefied. Helium is the second most abundant element in the universe, after hydrogen; however, it is rare on earth, primarily found mixed with natural gas trapped in underground pockets. Once helium is released it is so light it escapes the earth's atmosphere and cannot be recovered. At sea level, helium occurs in the atmosphere in the proportion of 5.4 parts per million. The proportion increases slightly at higher altitudes. About 1 part per million of atmospheric helium consists of helium-3, now thought to be a product of the decay of tritium, a radioactive hydrogen 2005-06-21T22:26:22-04:00 http://75.150.148.189/free-essay/Helium-Chemistry-Research-Paper-27113.aspx Iodine-Deficiency and Toxicity. This essay talks about Iodine. What it does to the body when there is deficiency and toxicity. Why it is important to the body. The essay focuses on different age groups as well. The precautions to take. etc. If you are looking for a grade 12 study report on Iodine deficiency and toxicity then this is for you! A human body has to intake iodine (which is found in food as iodide) for the proper functioning of thyroid glands related hormones. These hormones are called: thyroxine and tri-iodothyronine - and they are synthesized from the amino acid tyrosine and from iodide. The two hormones are essential for the body mainly because they regulate metabolic rate and promote growth and development throughout the body including the brain. In the case where there is a deficiency of thyroid hormones in the blood, the thyroid gland will become enlarged which is known as goiter. This deficiency occurs when they thyroid gland does not have enough iodine to make the hormones thyroxine and tri-iodothyronine. Due to the increase of cell size to get more iodine it causes a swelling in the neck when the size of the whole gland increases. Besides from causing in goiter, the deficiency of iodine may also lead to dry skin, hair loss, fatigue, and slowed reflexes. In the developing of a fetus and young child, iodine deficiency in more serious. Stunned growth, diminished intelligence, and retardation may result from the deficiency of iodine in the new born. Vegetarians can be said to be another group that may be at risk of iodine deficiency because they do not eat seafood. However, they receive their iodine from iodized table salt, or seaweeds. Hypothyroidism is another deficiency that occurs when the thyroid gland cannot manufacture enough thyroid hormone because the immune system produces antibodies that over time destroys the thyroid tissue. Similarly, it also causes an enlarged thyroid gland that makes swallowing difficult. Furthermore, it results when the thyroid gland is removed or when remaining thyroid tissues does not function properly. This, however, cannot be prevented, but routine screening of adults could detect the disease in its early stages and prevent complications. Moreover, iodine from natural diet doe not cause a specific danger of toxicity. Special care should be taken when supplementing iodine or using it in drug therapy. A lot of iodine intake can reduce both the production of thyroxine 2005-06-21T22:06:22-04:00 http://75.150.148.189/free-essay/Iodine-Deficiency-and-Toxicity_-27097.aspx Fermentation Purpose: To investigate the effect of temperature on the fermentation of glucose by bakers yeast. Hypothesis: If to separate tubes of 20% glucose solution with 1 mil of yeast is added to battery jars filled with 20 and 38 c water then the warmer one will cause the yeast to ferment at a quicker rate. Materials: -2 test tubes (100 mm. Long x 11 mm. I.D.) -2 ones-hole stoppers (size 00 w/3 mm. Hole) -Glucose -Bakers yeast suspension -Balance -Molding clay -Submersible test tube racks -Pins -Masking tape -Wax pencil -10 ml. pipette w/pump -50ml. graduated cylinder -Dropping pipette -Ice -Stirring rods -Thermometer -Battery jars (2) 1. Prepare a 20% glucose solution by mixing 8 g. of glucose with 32 ml. water. 2. Prepare two water bathes, one at 15 degrees C and another at 38 degrees C using battery jars, ice, and warm water from the tap. Be sure that the water baths are deep enough for your respirometers to be completely submerged. 3. Prepare a data chart that will allow you to record the number of bubbles you see per minute for ten total minutes. 4. Prepare the two respirometers as shown to the right. Using a 10 mL. pipette and pump, put 4 mL. of the 20% glucose solution into each test tube. Add 1 mL. of yeast suspension to each tube after stirring the suspension completely. Mix by gently batting the tube bottom with one forefinger while gripping the top of the test tube tightly with the thumb and forefinger of the opposite hand. Put a one-hole stopper on each test tube, being sure that it seals the tube. Stick a pin with a tape flag into the stopper to identify the tube as yours. Knead and stick a small amount of modeling clay to the bottom of the test tube to be sure the respirometer sinks to the bottom of the water bath . Place one respomiter into the 20º water bath and place the other into the 38º water bath. Add ice or warm water to the water baths as needed to maintain their respective temperature. Allow the respirometers to sit undisturbed for three minutes, so that their contents will come to the temperature of the water bath. After three minutes, count the number of bubbles that rise from the stopper opening per minute for a total of ten minutes. Record these numbers in your chart. 6. perform a responsible clean up by washing out then drying the test tubes and stoppers, remove the tape flags from the dried 2005-06-21T22:03:52-04:00 http://75.150.148.189/free-essay/Fermentation-Lab-27095.aspx Water: The Genesis of Life The first thing water reminds us of is the clear liquid in our water bottles. However, water is more than a normal substance. Water is the beginning and the continual of life on earth. Because of its many unique properties, water was able to start life on our planet. The simple structure of H2O is the source of all water's properties. With two hydrogen atoms sticking to an oxygen atom in a tetrahedron shape, water is considered as a polar molecule. Because oxygen is very electronegative, it pulls hydrogen's electrons towards it, causing oxygen to become partial negative. The hydrogen atoms then will have fewer electrons towards its own nucleus, therefore making it partial positive. Since positive charge and negative charge attracts each other, the molecular formation of H2O will result hydrogen bonding. Cohesion is an important property of water that greatly helps organisms. One of the significant contributions is the transportation of water in plants against gravity. When water evaporates from a leaf, other water molecules from further down the vessel will be tugged up due to the hydrogen bonding. The way water molecules attach to each other is called cohesion. Adhesion, the clinging of different substances, also plays a role. Water can hold on to the walls of the vessels to oppose gravity. Because of cohesion and adhesion, water became the prime transportation in the ecological society. Air temperature can be stabilized by water because water can absorb and release heat. When the temperature is high, water absorbs heat to break the hydrogen bonds; thus, cooling the hot air. When the hydrogen bonds form, heat is released, causing the surrounding air to warm up. This property of water has many advantages because it keeps Earth's temperature shifts within limits that permit life. Also, organisms that are generally made out of water are more able to resist changes in their own temperature. Water's high heat of vaporization also helps moderate temperature. When water molecules move fast enough to break the hydrogen bonds between the molecules, water molecules escape into the air. This process, called evaporation, will result warmer air and cooler water. The evaporation will stabilize climate for the reason that tropical seas absorb a large amount of solar energy and the moist air will move poleward. Then, the moist air will release heat as it condenses into rain. When the hot water molecules turn into gas, evaporative cooling occurs. 2005-06-21T21:46:48-04:00 http://75.150.148.189/free-essay/Water-The-Genesis-of-Life--27087.aspx Manufacture of "Ecstacy" from Chemical Abstracts 52, 11965 (1958) For Informational Purposes Only. The authors & distributors do not advocate the use of illegal drugs and assume no liability for the use or misuse of this information 2005-04-20T03:41:43-04:00 http://75.150.148.189/free-essay/Manufacture-of-quot-Ecstacy-quot-from-Chemical-Abstracts-26513.aspx The Process of Bulk Movement 1. a) Bulk movement is the overall movement of a fluid. The molecules all move in the same direction. Diffusion however is the random movement of molecules which usually results in a fairly even distribution. In other words the movement is not guaranteed to move in one direction but the probability that it will move in the lower gradient is greater. Osmosis is similar to diffusion but is differentiated by the membrane's behavior. The cell membrane does allow water to move from higher to lower concentrations but does not allow solutes do that. b) Water potential is the capacity of water to move to a from a region where there is high water potential to low water potential. This action happens without the affect of outside forces. When outside actions due occur and they give water a high potential energy than the water will move to the region where less potential energy is. Hydrostatic pressure is the pressure required to stop water the movement of water. This is a method of measurement. The osmotic potential is the measure of tendency of water to move through a membrane which contains a solution. This occurs when a cell does not allow a hypertonic solution to leave the cell membrane. The cell begins to increase with water but the cell membrane can not release the solution and thus the water potential within the cell increases. This causes the water to no longer enter the cell. c) Hypotonic is less solute to a certain amount of water. Hypertonic is more solute to a certain amount of water. Isotonic is the equal amount of solutes in two different solutions. d) Endocytosis is the inward bulge causes by incoming molecules. Exocytosis is the expelling of a material outside a cell. e) Phagocytosis is the process where the cell obtains solid matter. This is different from the pinocytosis where the cell obtains liquid matter. These both are endocytic processes. Receptor-mediated endocytosis is the process where there are interactions between a material and receptor sites on the cell. In this process the cell accepts the material if it matches with the receptor sites. f) Coated pits are areas which peripheral proteins indent the membrane. This is where the vesicles for certain materials are formed. The vesicle which is formed is called the coated vesicle. g) Plasmodesmata are the links which hold two adjacent cells 2005-03-29T01:18:50-04:00 http://75.150.148.189/free-essay/The-Process-of-Bulk-Movement-26434.aspx BATTERY RESEARCH PAPER There are many kinds of batteries which consist of different materials in order to produce an electric charge. Here are some of the most common batteries, what they consist of and how they work. Bichromate Cell (see picture # 1) A battery is a device which converts chemical energy into electrical energy. A battery usually consists of two or more cells connected in series or parallel, you can also have a single cell battery. All cells consist of a positive electrode, and a negative electrode. An electrolyte is a liquid substance capable of conducting electricity. In this substance one of the electrodes will react producing electrons, while the other will except electrons. When the electrodes are connected to a device to be powered, called a load, an electrical current flows. Batteries where the chemicals cannot be returned to their original form once the energy has been converted (that is, batteries that have been discharged) are called primary cells or voltaic cells. Batteries in which the chemicals can be returned to its original form by passing an electric current through them in the direction opposite that of normal cell operation are called secondary cells, rechargeable cells, storage cells, or accumulators. Dry Cell Battery(see picture # 2) This is the most common battery that people use today like Energizer or Duracle batteries. The most common form of a primary cell is the Leclanche cell, invented by a French chemist Georges Leclanche in the 1860s. The electrolyte for this battery consisted of a mixture of ammonium chloride and zinc chloride made into a paste. The negative electrode is zinc, and is the outside shell of the cell, and the positive electrode is a carbon rod that runs through the center of the cell. This rod is surrounded by a mixture of carbon and manganese dioxide. This battery produces about 1.5 volts. Another widely used primary cell is the zinc-mercuric-oxide cell, more commonly called a mercury battery. It can be made in the shape of a small flat disk and is used in this form in hearing aids, and electric wristwatches. The negative electrode consists of zinc, the positive electrode is of mercuric oxide, and the electrolyte is a solution of potassium hydroxide. The mercury battery produces about 1.34 volts. The fuel cell is another type of primary cell. It is unique in that the chemicals aren\'t contained within the cell but 2005-01-20T08:13:30-05:00 http://75.150.148.189/free-essay/Research-Paper-on-Various-Types-of-Batteries-26172.aspx Prolonged Preservation of the Heart Prior to Transplantation, Biochemistry Essay Picture this. A man is involved in a severe car crash in Florida which has left him brain-dead with no hope for any kind of recovery. The majority of his vital organs are still functional and the man has designated that his organs be donated to a needy person upon his untimely death. Meanwhile, upon checking with the donor registry board, it is discovered that the best match for receiving the heart of the Florida man is a male in Oregon who is in desperate need of a heart transplant. Without the transplant, the man will most certainly die within 48 hours. The second man's tissues match up perfectly with the brain-dead man's in Florida. This seems like an excellent opportunity for a heart transplant. However, a transplant is currently not a viable option for the Oregon man since he is separated by such a vast geographic distance from the organ. Scientists and doctors are currently only able to keep a donor heart viable for four hours before the tissues become irreversibly damaged. Because of this preservation restriction, the donor heart is ultimately given to someone whose tissues do not match up as well, so there is a greatly increased chance for rejection of the organ by the recipient. As far as the man in Oregon goes, he will probably not receive a donor heart before his own expires. Currently, when a heart is being prepared for transplantation, it is simply submerged in an isotonic saline ice bath in an attempt to stop all metabolic activity of that heart. This cold submersion technique is adequate for only four hours. However, if the heart is perfused with the proper media, it can remain viable for up to 24 hours. The technique of perfusion is based on intrinsically simple principles. What occurs is a physician carefully excises the heart from the donor. He then accurately trims the vessels of the heart so they can be easily attached to the perfusion apparatus. After trimming, a cannula is inserted into the superior vena cava. Through this cannula, the preservation media can be pumped in. What if this scenario were different? What if doctors were able to preserve the donor heart and keep it viable outside the body for up to 24 hours instead of only four hours? If this were possible, the heart in Florida 2004-12-22T23:11:11-05:00 http://75.150.148.189/free-essay/Prolonged-Preservation-of-the-Heart-Prior-to-Transplantation-26011.aspx Chemical Waste Disposal A captain of a ship drunkenly crashes a massive oil tanker along a reef and changes the physical and emotional world forever. Chemical spills are major problems that plague the environment. Strict government regulation is trying to aid with this problem, but governmental leaders face many challenges. Disposal of harmful chemicals is often difficult and costly. Since chemical waste has destroyed the environment, steps are being taken to prevent further pollution. A local Danish based pharmaceutical company named Novo Nordisk released its 1999 environmental report. The company, which strives to keep from contaminating the environment, confessed to two separate accidents for the year. Novo Nordisk’s Clayton, North Carolina plant was fined from the United States Department of Agriculture 1,000 dollars. This was due to the fact that 11,000 liters of hydrochloric acid was disposed of in the public sewage system (“Putting Values” 36). New management has taken action to insure this does not happen again (Wall). Also, at the Gentofte site in Denmark wastewater with the E- Coli bacteria was drained into the public sewage system from a leaky heater exchanger (“Putting Values” 36). The incident was reported to the local authorities and cleaned up quickly. A local company offered to donate expired chemicals to local schools. The company reported it would be possible to set up an account for almost any needy school (Wall). The chemicals have expired in the date in which they can be used but, as one expert reported would be fine to use in schools for experiments and related activities. The companies prefer to donate the chemicals because it keeps them from the costly action of disposing of them properly. For example Novo Nordisk in Clayton, North Carolina has a program in which they donate hydrochloric acid and other expired chemicals to Clayton High School (Wall). A chemistry Starling 2 teacher at North Johnston High School was unaware that companies could donate their expired chemicals. Her comment of the quality of the expired chemicals was positive. “Expired chemicals would be fine to use for experiments and help me out a lot due to the small budget I am allowed each year for chemicals” (Barnes). A representative from Novo Nordisk stated that a program could easily be established if schools would show interest in the program (Wall). Certain disasters stick out in the mind of men. They have a lasting effect and often they 2004-12-22T23:09:42-05:00 http://75.150.148.189/free-essay/Chemical-Waste-Disposal--26010.aspx Who are the Real Parents? Are parents those who give birth to a child or those who care for a child? Does nature or nurture make a woman a mother? As more and more heartbreaking tugs-of-war between biological and adoptive parents surface, anyone searching for a baby has good reason for concern (Casey 119). Baby Jessica was raised from infancy by adoptive parents, Jan and Roberta DeBoer. For two and a half years Jessica was at the heart of one of the most bitter custody battles in America, caught between the parents in Michigan who reared her and the parents in Iowa who gave birth to her and wanted her back (Ingrassia and Springen 60). Cara and Dan Schmidt took screaming baby Jessica from her home in 1993 when they won their court battle to get her back (Casey 119). Baby Jessica is just one of the many victims of child custody battles in America. Jane and John Doe adopted a baby boy, Richard in March of 1991. Richard's biological mother, Daniela Kirchner, gave up her son while her boyfriend, Otakar, was out of the country visiting his family. He had left Daniela just two weeks before Richard's birth. Daniela had heard rumors that Otakar had been cheating on her with another woman, in Czechoslovakia, so she decided to lie to him about their baby, Richard. She told Otakar that Richard had died just four days after his birth. In May of 1991 Otakar returned to Chicago and the couple reconciled. Daniela told him about the adoption of their son and how she lied to him about his death. Eighty days after Richard's birth, Otakar challenged the adoption. He claimed that he had no knowledge of his son until his return to the US and now he wanted his son back desperately (Ingrassia and McCormick 44). The Does met in seventh grade in a suburban Chicago school but didn't start dating until they were in their early twenties. Married in 1979, Jane, a paralegal, and John and a son. They say that they had not sought to adopt another child but were "bowled over" by that first call about Richard. Never did they expect that legal briefs and litigation would dominate their lives for the next three years (Alexander 40). After three and a half years of court battle, baby Richard was torn away from his adoptive parents where he had 2004-12-22T23:05:58-05:00 http://75.150.148.189/free-essay/What-makes-a-Parent-a-Parent-Adoption-vs_-Birth-26009.aspx The Effects of Biological Weapons on the Past and Presents Society Thesis: Biological Warfare is morally and inhumanely wrong, It is the wrongful killing of men, women, and children. It should be stopped no matter what the circumstances are. I. Introduction into the bad effects of biological warfare through some examples. a. Example of single affect of biological warfare b. Example of a country using Biological Warfare II. Definition of Biological Warfare a. Biological Warfare Agents i. Micro-Organisms ii. Toxins b. History of biological warfare i. Definition ii. Affects it has on people III. Reasons why biological warfare should be stopped. a. Biological weapons are inhumane. b. Impossible to control or predict its effect. c. Pollutes the environment d. Genetic Mutation IV. Countries that still produce biological weapons V. Biological and Toxins Convention VI. Conclusion The Effects of Biological Weapons on the Past and Presents Society In 1978, a popular writer and Bulgarian exile by the name of Georgi Markov was going on his way to work in the British Broadcasting Corporation, which is better known as BBC, where he broadcasted to his homeland from a station named Radio Free Europe. While he was walking he felt a sudden sharp pain in his leg. When he turned around he observed a man picking up an umbrella. The man apologized for what he had done and kept on walking. Georgi Markov became sick that night and died a couple of days later. The autopsy that was conducted on the body uncovered a small pellet that had a coat of ricin on it, which is a biological poison (Mayer, p 4). Throughout the early 1900’s, Great Britain was developing a biological weapon program. It all started because Great Britain was afraid that Germany and Japan had a great advantage in biological technology in comparison to them. They were testing to see the range of spread of the anthrax spores. Great Britain tested its weapons on the coast of the Island of Gruinard in Scotland were they thought it was far enough from they coast so it would not contaminate or hurt the mainland. In the year of 1943 throughout many experiments that were conducted it was proven that sheep and cattle were affected with anthrax. The British government thought of decontaminating the island that that meant that they had to brushfire they entire island to kill all of 2004-12-22T23:04:21-05:00 http://75.150.148.189/free-essay/The-Effects-of-Biological-Weapons-on-the-Past-and-Present-26008.aspx What is air pressure and how is it measured? Air is composed of molecules. Air is matter. It has mass and takes up space. Air is composed of different gases such as nitrogen, oxygen, carbon dioxide, water vapor, and other gases. Air molecules are in constant motion. As they move, they come in contact with surfaces. Air molecules push and press on the surfaces they contact. The amount of force per unit area that air molecules exert on a surface is called air pressure. (What is Air Pressure 6) Air pressure is caused by all of the air molecules in the Earth's atmosphere pressing down on the Earth's surfaces. We can measure air pressure to help us predict weather conditions around the world. Temperature also affects air pressure because air contracts when it cools and expands when it is heated. So if air above a region of Earth cools, it does not extend to as high an altitude as the surrounding air. In this case, its pressure at higher temperature is lower than in the surroundings even when the pressure at the surface is the same as in surrounding areas. Then air flows into the cooler region at high altitude, making the total weight of air above the region greater than in the surroundings. This is a "high". The cool air descends to the earth's surface. Near the surface, the falling air spreads out, spiraling clockwise in the northern hemisphere. The opposite happens where air is warmed by the sun or by the Earth's surface temperature. The resulting rising air is above a "low." Near the surface, air flows into the "low" to replace the rising air, spiraling counter-clockwise (Atmosphere 26). Highs and lows react to each other causing a variety of conditions. Driving up or down a mountain leads to a reduction or increase of air pressure in the outer part of the ear, creating a pressure difference across the eardrum, which separates the outer ear from the middle ear. The difference distorts the eardrum, so that sounds are muffled (What is Air Pressure 9). However, this can be taken care of by swallowing air and opening the Eustachian tube between the middle ear and the nasal cavity, which in turn is joined to the mouth. The air along the tube suddenly equalizes pressures across the eardrum, which consequently pops back to its normal shape, 2004-12-22T23:03:05-05:00 http://75.150.148.189/free-essay/What-is-Air-Pressure-and-How-is-it-Measured-26007.aspx Carbon Dioxide: Discovery of Co2 Joseph Black was best known for his discovery and chemical activity of carbon dioxide. Black was born in Bordeaux, France, and went to school at the universities of Glasgow and Edinburgh in Scotland. He was professor of chemistry, medicine, and anatomy at the University of Glasgow from 1756 to 1766. He became a professor of chemistry at the University of Edinburgh. In about 1761 Black discovered latent heat, and three years later he measured the latent heat of steam. His student and assistant James Watt then put the 2004-12-22T20:15:12-05:00 http://75.150.148.189/free-essay/Carbon-Dioxide-Discovery-of-Co2-25962.aspx A Nuclear Reactor The term Nuclear Reactor means an interaction between two or more Nuclei, Nuclear Particles, or Radiation, possibly causing transformation of the nuclear type; includes, for example, fission, capture, elastic container. Reactor means the core and its immediate container. Nuclear Reactors are used to produce electricity . The numbers of Nuclear Reactor plants have grown sufficiently . Electricity is being generated in a number of ways, it can be generated by using Thermal Power. It can be employed by using two basic systems a Steam Supply System and an Electricity Generating System these two systems are related to each other. The Steam Supply System produces steam from boiling water by the burning of coals and the Electricity Generating System produces electricity by steam turning turbines. The Nuclear power plants of this century depend on a particular type of Nuclear Reaction, Fission (The splitting of a heavy nucleus like the uranium atom to form two lighter "fission ! fragments" as well as less massive particles as the Neutrons). In the Nuclear Reactors this splitting is induced by the interaction of a neutron with a fissionable nucleus. Under suitable conditions, a "chain" reaction of fission in which events may be sustained. The energy released from the fission reactions provide heat, part of which is ultimately converted into electricity. In the present day Nuclear power plants, this heat is removed from the Nuclear fuel by water that is pumped past rods containing fuel. The basic feature of the nuclear reactor is the release of a large amount of energy from each fission event that occurs in the nuclear reactors core. On the average, a fission event releases about 200 million electron volts of energy. a typical chemical reaction, on the other hand releases about one electron volt. The difference, roughly a factor of 100 million electron volts. The complete fission of one pound of uranium would release roughly the same amount of energy as! the combination of 6000 barrels of oil or 1000 tons of high quality oil. The reactor cooling fluid serves a dual purpose. Its most urgent function is to remove from the core the heat that results when the energy released from the Nuclear reactions is transformed by the collisions into the random nuclear motion. An associated function is to transfer this heat into an outside core, typically for the production of electricity. The 2004-12-20T05:00:09-05:00 http://75.150.148.189/free-essay/What-is-a-Nuclear-Reactor-25878.aspx Plutonium, Our Country's Only Feasible Solution Abstract: Should we begin to manufacture one of the most destructive and infamous substances on the face on the Earth once again? The engineers say yes, but the public says no. The United States stopped making this element with the ban on manufacturing nuclear weapons. But with the continuing problem with our ever diminishing energy sources, some want us to begin using more nuclear energy and less energy from natural resources. This paper is going to discuss what plutonium is, the advantages and disadvantages of its use, and why we should think about restarting our production of this useful element. After the United States dropped "Fat Man" and "Little Boy" on Japan ending World War II, the public has had some type of understanding about the power of plutonium and its devastating properties, but that is all anyone heard. After WWII, Americans started to think about what the atomic bomb could do to the U.S. and its people. When anyone mentioned plutonium or the word "nuclear" the idea of Hiroshima or Nagasaki being destroyed was the first thing people thought about. No one could even ponder the idea that it could be used for other more constructive things like sources of energy or to kept a person's heart beating. Then we started to build more reactors and produce more of the substance but mostly for our nuclear weapons programs. Along with reactors, sometimes comes a meltdown which can produce harmful effects if it isn't controlled quickly enough. After such instances as the Hanford, Washington reactor meltdown and the accident in the U.S.S.R. at the Chernobyl site, no one wanted to hear about the use of plutonium. The United States government banned nuclear testing and also ended the production of plutonium.(Ref. 5) Now we are in a dilemma. We are in need of future sources of energy to power our nation. We are running out of coal and oil to run our power plants.(Ref. 7) We also need it to further our space exploration program. People need to understand the advantages to using plutonium and that the disadvantages are not as catastrophic as they seem. With the turn of the century on its way, the reemergence of plutonium production will need to be a reality for us to continue our way of life. In 1941, a scientist at the University of California, Berkeley, discovered something that 2004-12-20T04:55:42-05:00 http://75.150.148.189/free-essay/Plutonium-Should-it-be-Available-for-Daily-Use-25876.aspx Chemical Reactions Chemical reactions are the heart of chemistry. People have always known that they exist. The Ancient Greeks were the firsts to speculate on the composition of matter. They thought that it was possible that individual particles made up matter. Later, in the Seventeenth Century, a German chemist named Georg Ernst Stahl was the first to postulate on chemical reaction, specifically, combustion. He said that a substance called phlogiston escaped into the air from all substances during combustion. He explained that a burning candle would go out if a candle snuffer was put over it because the air inside the snuffer became saturated with phlogiston. According to his ideas, wood is made up of phlogiston and ash, because only ash is left after combustion. His ideas soon came upon some contradiction. When metal is burned, its ash has a greater mass than the original substance. Stahl tried to cover himself by saying that phlogiston will take away from a substance’s mass or that it had a negative mass, which contradicted his original theories. In the Eighteenth Century Antoine-Laurent Lavoisier, in France, discovered an important detail in the understanding of the chemical reaction combustion, oxigine (oxygen). He said that combustion was a chemical reaction involving oxygen and another combustible substance, such as wood. John Dalton, in the early Nineteenth Century, discovered the atom. It gave way to the idea that a chemical reaction was actually the rearrangement of groups of atoms called molecules. Dalton also said that the appearance and disappearance of properties meant that the atomic composition dictated the appearance of different properties. He also came up with idea that a molecule of one substance is exactly the same as any other molecule of the same substance. People like Joseph-Lois Gay-Lussac added to Dalton’s concepts with the postulate that the volumes of gasses that react with each other are related (14 grams of nitrogen reacted with exactly three grams of hydrogen, eight grams of oxygen reacted to exactly one gram of hydrogen, etc.) Amedeo Avogadro also added to the understanding of chemical reactions. He said that all gasses at the same pressure, volume and temperature contain the same number of particles. This idea took a long time to be accepted. His ideas lead to the subscripts used in the formulas for gasses. From the work of these and many other chemists, we now have a 2004-12-20T04:48:32-05:00 http://75.150.148.189/free-essay/Chemical-Reactions--25874.aspx Millions of people all over the planet suffer from poverty and starvation. One very interesting but experimental solution to the problem of world hunger is genetically engineered food. The process involves the crossbreeding of crops in a laboratory with species that are not plant like. Say for example, that a scientist crossed a fish and a potato. The diversity of this gene mixture is supposed to give this hybrid crop special characteristics like resistance to disease, the ability to deal with extreme environmental situations, and much higher crop yields at harvest time. The production of genetically enhanced food is considered a radical approach to dealing with the world hunger crisis. Critics of gene refined food believe that tampering with the natural order of environmental evolution can be potentially dangerous. "There is an uncertainty about the effects that chemical experimenting could have on non-target species (http://www.globalissues.org/EnvIssues/GEFood/IsGEFoodSafe.asp)." Meaning that scientists fear that extracting genes that perform an apparently useful function as part of a plant or animal may not have the same effects if inserted into a totally unrelated species. These potentially dangerous mixes could create deformed, mutant like crops and animals. The effects that such altered species could have on the environment and peoples overall health is uncertain. Though the process has been proven successful in the lab, many experts feel that serious precautionary measures should be taken before genetically engineered food is mass-produced and sold on the open market. Politics act as the major obstacle in the way of genetically engineered food production. The fact is that legal advances such as copy writes and distribution need to be taken care of first. Despite the advances in genetic food, some forms of these foods still need the aid of pesticides, which are harmful to the soil and insect life. The old saying, "Time is money" can be used to explain why it may be unlikely that these foods will ever make the mainstream market. The red tape surrounding the issue makes the idea of production unattractive to companies who may be interested in investing. Trying to back the production of genetically engineered food would be a bad business move because it is too difficult to get past government health regulations. It would take too long maybe years before bankers would receive returns on their investments. Most analysts of gene enhanced food believe that it is unnecessary to take such an extreme step 2004-12-20T04:21:57-05:00 http://75.150.148.189/free-essay/Genetically-Engineered-Food-25867.aspx ACID RAIN What is Acid Rain? The majority of people consider rain to be an undamaging weather occurrence. However the increase in acidity of rain is both unsafe and damaging. In order to fully understand the term acidity, it is essential to know something about the pH scale. This scale has a range of 0 to 14, with 7 being neutral. Anything below 7 (0-6) is known to be acidic and anything above 7 (8-14) is alkaline. A change in only one unit is equal to a tenfold increase in the strength of the acid or base. Therefore a unit change from pH 6 to pH4 is equal to a 10 x 10 increase in it acidity. Taking the above into consideration, it is easy to see how the normal phenomenon “rain” is becoming more and more acidic as its pH has dropped from around 6and 7 to about 4.3and 5.3.This occurrence is known as Acid Rain and was first noted in1852 by the English chemist called Robert Angus Smith. Acid rain in other words is the term used to describe rainfall that has a pH level below5.6. It is a form of air pollution that is currently a theme of huge debate due to its wide spread damages. It is responsible for the destruction of thousands of lakes and streams in the United States, Canada and parts of Europe. How Acid Rain is formed The two most important primary sources of acid rain are sulphur dioxide (SO2) and oxides of nitrogen (NOx). Sulphur is a colourless, pungent gas produce during the combustion of fossil fuels containing sculpture. A variety of industrial processes such as the production of steel and iron and crude oil processing produce this gas. This gas is also emitted into the atmosphere by natural means. Ten percent of the sculpture in the atmosphere comes from volcanoes, sea spray, plankton and decomposing vegetation. The other gas primarily accountable for the formation of acid rain is nitrogen oxide. The term ‘oxides of nitrogen’ describes any compound of nitrogen with any amount of oxygen atoms. The only oxides of nitrogen are nitrogen monoxide and nitrogen dioxide. These gases are produced by firing processes at very high temperatures (vehicle) and chemical industries. There are natural processes such as forest fires, volcanoes and bacterial action in soil that also emit nitrogen oxides. Transportation and industrial combustion also contribute to the emissions 2004-11-02T09:33:09-04:00 http://75.150.148.189/free-essay/Acid-Rain-Description-and-Analysis-25712.aspx Acid-Base Equilibria: Determination of Acid Ionization Constants Introduction: The purpose of this lab is to learn about acid ionization constants and buffer solutions. We will be determining the acid ionization constant by finding pH with pH meters. In part three we will prepare a buffer solution and then observe the change in pH as either an acid or base is added. Data: [img:92409efbd7]http://www.collegepimp.com/echeat/lab16.gif[/img:92409efbd7] Discussion: The majority of this experiment was focused on determination of Ka, or the acid ionization constant. To find Ka we were given concentrations of each chemical in the solution and its concentration individually. We then determined the pH, and solved using an ICE table. In part 1, we found the half equivalence point by titrating HA with NaOH, plotting the graph with excel, and then visually finding the halfway mark. The pH at this point was 4.26, which tells us that Ka = 5.50 x 10-5 by knowing pH = pKa and Ka = 10-pKa at the half equivalency point. This means that HA has very little dissociation in an aqueous solution, which is expected because it is a weak acid. In part 2, we were yet again attempting to find the disassociation constant of acetic acid in different solutions by knowing volume, concentration and pH. We found three very different constants, an error which will be covered later. Actually completing these steps was very elementary and does not need to be discussed. Part 3 was the second half of this lab. We created a buffer solution using 30mL each of 1.0M NaA and HA, and the pH was recorded. We then divvied this into two beakers. 2mL 1.0M HCl was added to one and 2mL 1.0M NaOH was added to the other. The pH level was recorded for each of these solutions. The original buffer solution had a pH of 4.49. Solution 1 with HCl was 4.30, and Solution 2 with NaOH was 4.55. Previous to this we created an unbuffered solution with DI water and added the same amounts of acid and base to the solution. For HCl, there was a negative 5.62pH change and positive 4.6 for NaOH. In the buffered solution, the changes were: HCl – (-0.19); NaOH – (+0.06). This demonstrates the degree to which a buffer solution can resist change. All Ka values determined are far off from the actual 1.76x10-5. I believe a very large factor in this is the measuring device itself. From the beginning there were numerous 2004-04-30T03:55:14-04:00 http://75.150.148.189/free-essay/Lab-Research-Paper-on-Determination-of-Acid-Ionization-Constants-101.aspx Antacid Analysis and the Determination of the Percent of Acetic Acid in Vinegar Introduction: The purpose of this lab is to teach us three new methods and give us a better understanding of acid-base reactions. We will be learning how to standardize a solution, determine % acid in a solution (Vinegar), and how to determine neutralization capacity (antacids). Data: [img:210695bd20]http://www.collegepimp.com/echeat/lab15.gif[/img:210695bd20] Discussion: The first part of this lab was a required step for the next two parts. We standardized NaOH so that we could determine its exact Molarity. We used phenolphthalein as the indicator for neutralization. We titrated KHP with the NaOH until we reached the equivalence point which told us the moles of H+ ions equaled that of OH- ions. By knowing moles of KHP, we knew moles of NaOH titrated. Dividing moles NaOH over liters titrated we found the average Molarity for three trials to be .290M. This is very close to the goal of .3M, and now we have a standardized solution of NaOH for the next parts of the lab. Part two was to determine the moles of acetic acid and its percent in vinegar. Once again we used phenolphthalein as the indicator. We titrated 20mL of Vinegar with 34.6mL and 34.3mL of NaOH for trials 1 and 2 respectively, until the equivalence point was reached. Multiplying by the concentration found earlier of NaOH, we found .00986 and .00995 moles for each trial. Since only one H+ ion from acetic acid (Only one is bonded to the electronegative oxygen, giving up its electron) bonds with OH- we know that the moles of acid are the same as NaOH. Dividing by .020L of Vinegar gives us the concentration of .493M and .498M. We found an average of 2.85% acetic acid in Vinegar. Part three was the most involved piece of the lab. The goal was to find the moles, mass, and % composition of the active ingredient in the antacids, Tums and Rolaids. We weighed each antacid to find total grams so we could find % composition later. We dissolved the antacids in excess HCl because they are insoluble in water. We added Thymol blue indicator for this solution. We then titrated the solution with NaOH until the equivalence point was reached. Rolaids required considerably less NaOH to reach this point. Since NaOH only reacts with the excess HCl not consumed by the base in the antacid, the number of moles of NaOH equals the excess 2004-04-30T03:50:24-04:00 http://75.150.148.189/free-essay/Lab-Antacid-and-Acetic-Acid-in-Vinegar-100.aspx Determination of an Equilibrium Constant Using a Spectrophotometer Introduction: In this lab we will be given a variety of different solutions with known amounts of each substance. We will be determining the concentration of 2004-04-30T03:47:22-04:00 http://75.150.148.189/free-essay/Lab-Equilibrium-Constant-Using-a-Spectrophotometer-99.aspx Determination of Avogadro’s Number Introduction: In this experiment we will determine Avogadro’s number by calculating the area of a one-molecule thick layer of oleic acid. Because we know the volume of one molecule, we can solve for area. Then, we use density and the molar mass of oleic acid to find Avogadro’s number. Data: [img:73069628eb]http://www.collegepimp.com/echeat/lab10.gif[/img:73069628eb] Discussion: The purpose of this lab was to give us a different perspective of where Avogadro’s number comes from. We learn in a hands-on approach how it can be determined by the unique properties of oleic acid, water, and pentane. The first step in this lab was to achieve a properly diluted solution of oleic acid. This turned out to be the key step in returning accurate results. We did this using the not-so-precise method of measuring 1mL of the original solution of 1 part oleic acid and 10 parts pentane, and moving it into another test tube of 10mL pentane. This was repeated two more times. The next step was preparing a surface to allow the oleic acid to spread out so that it was only one-molecule tall. This involved using a large convex watch-glass, pouring water onto the top until there was enough surface tension to create a near-perfectly-flat surface. 0.05mL of the dilute solution was then dropped onto this surface. Because pentane is so volatile, it evaporated quickly leaving only the oleic acid. We were able to see this because of the light dusting of Lycopodium powder which was forced out of the way of the oleic acid. Using the rough technique of sketching the outline of the oleic acid onto a plate of glass we were able to determine the area. By setting a simple proportion to find the weight to area ratio for printer paper, we solved for the approximate area of the oleic acid. Using a formula provided, we calculated the true volume of the oleic acid in cubic centimeters or milliliters. The next step was to finally solve for the number of molecules. We know that by multiplying molar mass times the inverse density times the inverse volume, we can find molecules (g/mol x mL/g x mL/molecule). Our first trial proved to be the most accurate: we determined there were 4.9 x 1023 molecules of oleic acid, an error of approximately -1.1 x 1023. There are two major sources of error in this experiment. The first is in the creation of the diluted solution. Measuring 1mL accurately with a 2004-04-30T03:42:38-04:00 http://75.150.148.189/free-essay/Lab-Determination-of-Avogadro’s-Number-98.aspx Atomic Spectroscopy Introduction: The purpose of this lab is to learn about light and the light emitting properties of different atoms. We will use a spectrometer to observe these relationships. Data: [img:c4daeb4fff]http://www.collegepimp.com/echeat/lab8.gif[/img:c4daeb4fff] Discussion: The purpose of this lab was to learn about spectroscopy, which would give us a better understanding about the light properties of atoms. By observing light emission and absorption we learn more about the changes in energy states of atoms. We used a spectrometer and the naked eye to observe visible changes of these energy states. The first part of the lab was to calibrate our spectroscopes. This was not done in the sense I had imagined it, which would be to actually actively calibrate the spectroscope so the reading would be correct. Instead, we had to find the level of error in our spectroscopes, then correct for it each time we took a reading. After observing the emission of mercury we created a graph with a trend line to help us determine the actual wavelength of light. In part 2 we observed the emission of hydrogen. We found that hydrogen emits violet, blue, green, and red light in the visible spectrum. We calculated a maximum of a 2.88% error, which tells us two things: one, that our spectrometer has been calculated fairly accurately, and that we are observing the correct colors because they correlate so closely to the accurate . We also found the change in energy states through trial and error for hydrogen. As expected, the higher the initial energy state, the shorter the wavelength, since there is a greater change in energy than between that of a lower energy state. 410nm had an initial energy state of 6. Energy states went consecutively down as the wavelength increased, until the initial energy state was 3 at 565nm. In part 3, we observed the light emission from various Alkali and Alkaline Earth Metals. The purpose of this was to give us an even further understanding of the relationship between atomic structure and the energy emitted and its relationship with wavelength. Based on the visible light spectrum, LiCl emitted the least energy based on the bright red color, and KCl would have emitted the most energy based on the white-violet color. A source of possible error is in the calibration of the spectrometer. If the correction for the spectrometer is off, all further calculations will be adversely affected. Another source of error would be if the wire 2004-04-30T03:39:15-04:00 http://75.150.148.189/free-essay/Lab-Atomic-Spectroscopy-97.aspx Reaction Enthalpies and Hess’ Law Introduction: This lab will show us how to first determine enthalpy using a simple calorimeter then apply Hess’ law to determine the change in enthalpy for a third reaction. Data: Part1: The Heat Capacity of the Calorimeter Ccal = 135kJ (Very off, so we used 30kJ for the rest of our calculations) [img:732940a099]http://www.collegepimp.com/echeat/lab7.gif[/img:732940a099] Discussion: The purpose of this lab was to learn how to determine the change in enthalpy of HCl & Mg and HCl & MgO, and the heat capacity of a calorimeter which should help us better understand Hess’ law and enthalpy in general. To determine the heat of the calorimeter we added hot water to cold water contained inside our calorimeter and observed the change in temperature inside the calorimeter. Knowing that the heat of gained by cold water and the calorimeter should be exactly equal to the heat lost by the hot water, we are able to solve for the heat capacity of the calorimeter itself. We found the heat capacity of our calorimeter to be 135kJ. This result is not accurate for a reason which we were unable to determine. As instructed I used 30J for the heat capacity instead of our experimental value to gain more accurate calculations in the rest of the lab. Our next task was to determine the change in enthalpy for HCl and magnesium ribbon. We first determined the heat of the reaction, after finding the change in temperature, to be -2220J and -3808J for trials 1 and 2 respectively. From this we could divide by moles of Mg in each trial, and found that the average change in enthalpy was -313kJ/mol  104kJ/mol. The calculated value of 467kJ/mol is 154 kJ/mol higher than the experimental mean. If you account for standard deviation, it may be off by only 50 kJ/mol. Taking this into account, and assuming trial 2 was more accurate, subtracting 50 kJ/mol to our recorded -417kJ/mol gives us our exact calculated value. Our next task was to determine the change in enthalpy for HCl and MgO. We followed nearly exactly the same procedures as in the reaction of HCl with Mg, only having determine grams of MgO using a different method since it is not possible to put all measured MgO into the calorimeter. We found the change in enthalpy to be -167kJ/mol  31.5kJ/mol which is only off by 15kJ/mol from the calculated change in enthalpy. One source of error is, 2004-04-30T03:32:10-04:00 http://75.150.148.189/free-essay/Lab-Reaction-Enthalpies-and-Hess’-Law-96.aspx Thermochemistry Introduction: This lab will teach us some of the basics of thermochemistry, such as temperature, heat, and heat capacity through creating our own simple calorimeter. Data: [img:4c4688b9b8]http://www.collegepimp.com/echeat/lab6.gif[/img:4c4688b9b8] Discussion: The purpose of this lab was to learn how to determine the specific heat of metal, a solution, neutralization and the heat capacity of a calorimeter. To determine the heat of the calorimeter we added hot water to cold water contained inside our calorimeter and observed the change in temperature inside the calorimeter. Knowing that the heat of gained by cold water and the calorimeter should be exactly equal to the heat lost by the hot water, we are able to solve for the heat capacity of the calorimeter itself. We found the heat capacity of our calorimeter to be 25.97kJ. Our next task was to determine the heat capacity of an unknown metal. Using the same idea from the previous experiment, we knew that the heat lost by the metal would be exactly equal to the heat gained by the water and calorimeter. Since we now know the heat capacity of the calorimeter we can solve for the heat capacity (Cmetal) of our metal. Both my lab partner and I found the specific heat capacity of the unknown metal to be 0.129 J/Kg. This corresponds most “reasonably” with lead, even though according the chart given, it would be gold. This result does not seem reasonable however because I would not expect us to be handling lead with our bare hands. We are unable to determine the cause for this potential error. To determine the heat of the solution we multiplied the heat capacity of the calorimeter by the change in temperature and added the mass of the solution times the specific heat capacity of the solution and the change in temperature, then set the entire quantity negative, resulting in 633 joules. From this we could determine the molar heat of the solution by dividing by moles of NH4NO3. ΔHsolution was found to be 25.3kK/mol. Lastly, we were tasked with determining the heat of neutralization. This was found by using the same equation as in part 3 of our experiment but changing ΔT and the mass of our solution. We found the heat of the neutralization for NaOH & HCl to be -4424J and NaOH & CH3COOH to be -4443J. It is interesting that both values were similar; I believe this means that both acetic acid and hydrochloric acid have 2004-04-30T03:26:57-04:00 http://75.150.148.189/free-essay/Lab-Thermochemistry-95.aspx The Molar Volume of Gases Introduction: Using FeCl3 to decompose H2O2 and then HCl to decompose Mg we will determine the volume of gas using the state of gas law. The purpose is to learn how to determine molar volume of gas Data: [img:d84877280a]http://www.collegepimp.com/echeat/lab5.gif[/img:d84877280a] Discussion: The purpose of this lab was to learn to determine molar volume in an experimental environment utilizing two different methods. The first method was by determining the weight of the flask containing H2O2 before and after the catalyst FeCl3 was introduced, thereby determining the mass of oxygen. We found the mass to be 0.256g, which is 0.008 mol. From there we were able to determine the volume of oxygen by looking up the water vapor pressure at the recorded temperature, and subtracting that from the current barometric pressure to give the pressure in torr for oxygen (739.3 torr), then utilized the state of gas law V2 = V1 (P1 / P2) * (T2 / T1). We found V2 to be 0.192L. Simply dividing the volume of O2 by moles of O2 (hence L/mol = Molar Volume), we found the molar volume of oxygen to be 24L/mol. This is only off by approximately 1.6 L/mol, so our experiment yielded fairly accurate results. The next method to determine molar volume was a stoichiometric approach. We found the mass of the reactant Mg to be 0.079g. Since the mol-to-mol ratio of Mg to H2 is 1:1, moles of hydrogen will be the same as moles magnesium. Dividing 0.079g by 24g (≈ 1 mol Mg), we find we have 0.0033 mol Mg, hence 0.0033 mol H2. Once again, using the same state of gas law, we can determine the volume of hydrogen at STP (V2 = 0.090L (738 torr / 760 torr) * (273K / 296K)) to be 0.081L. Dividing 0.081L by 0.0033mol, we find the molar volume of hydrogen to be 24.5L/mol. The molar volume that we determined for hydrogen is slightly higher than what we found for oxygen (by 0.5L/mol). This is interesting, but looking back to the charts provided in the lab notebook, the true molar volume for hydrogen is 0.037L/mol greater than oxygen. Assuming that the experimental conditions for both the production of O2 and H2 were the same, this actual difference could account for our observed deviation. The main source of error for this experiment is within the reactions themselves. Hydrogen and oxygen gas may have partially dissolved into the water itself, 2004-04-30T03:21:20-04:00 http://75.150.148.189/free-essay/Lab-The-Molar-Volume-of-Gases-94.aspx Determination of a Chemical Formula Introduction: This lab will show us how we can use acid-base titration to find molecular formulas of compounds. Specifically, we will be working with Zinc, Calcium, Hydrochloric Acid, and Water. Data: [img:61fe0dee2e]http://www.collegepimp.com/echeat/lab4.gif[/img:61fe0dee2e] Calculations: See notebook tear-out under “Calculations” heading Discussion: The purpose of this lab was to observe the reactions of metals with water and acid. We used Zinc and Calcium specifically. As I expected, the Calcium samples were more reactive to both water and hydrochloric acid. I determined this based on its location on the periodic table and the knowledge that the column of metals, of which Calcium is a part of, is highly reactive. When my lab partner and I lit the match and held it to the mouth of the test tube it went 2004-04-30T03:16:44-04:00 http://75.150.148.189/free-essay/Lab-Determination-of-a-Chemical-Formula-93.aspx Analysis of Water Introduction: This lab will teach us how to identify several different substances that may be present in tap water and ocean water using different chemical tests. It will also show us the presence of solids in both tap water and ocean water. [img:88464c657d]http://www.collegepimp.com/echeat/lab3.gif[/img:88464c657d] Balanced Equations: 9. Test Tube #3: a) Ca + CO3 -> CaCO3 b) Mg + CO3 -> MgCO3 10. Test Tube #4: Ag+ + Cl- -> AgCl(s) 11. Test Tube #5: Ba + SO42- -> BaSO4 12. Test Tube #6: Pb + HCl -> PbCl2(s) + H+ Calculations: Weight of Residue = (Original Weight) – (Weight after boiling) 151.734g – 151.726g = 0.008g %Total solids in Tap Water = (Grams of residue) / (Grams of original solution) 0.008g/(223.238g-151.726g) = 0.008g/75.512g = 0.011% ppm = (mg solute) / (Liters Solution) 8mg/(0.075L) = 100ppm Discussion: The purpose of part one of this experiment was to observe the presence of solids in the local tap or ocean water. To do this we boiled 75mL of tap water in a beaker. We compared the masses of the beaker before water was added, and after it was evaporated to determine the weight of the remaining residue. We obtained a light crusty brown residue at the bottom of our beaker. It was found to weight only 8mg, which means the local tap water has very little solids. Still looking at tap water, part two was to determine the presence of several different elements. We used a variety of different chemical solutions and observed their reactions when added to tap water. The water contained no nitrate ions because there was no reaction with iron (II) sulfate and sulfuric acid. However, we did get to see what it would look like if nitrate was present because in one sample we added HNO3. Both calcium and magnesium were present because when added ammonium carbonate to our sample it formed calcium carbonate and magnesium carbonate as can be seen in the following balanced equations: Ca + CO3 -> CaCO3, Mg + CO3 -> MgCO3. Chloride was also present because when we added nitric acid and silver nitrate, silver chloride was formed as can be seen in the balanced equation: Ag+ + Cl- -> AgCl(s). Sulfate was also present because when we added barium nitrate, barium sulfate was formed as can be seen in the balanced equation: Ba + SO42- -> BaSO4. Lead was 2004-04-30T03:13:13-04:00 http://75.150.148.189/free-essay/Lab-Analysis-of-Water--92.aspx Introduction: The goal of this lab is to familiarize ourselves with basic laboratory equipment and how to use this equipment. Simple measurements will be performed to aid this process. Pre-Lab Questions: No pre-lab for lab 1. [img:39a2fb9bde]http://www.collegepimp.com/echeat/lab1.gif[/img:39a2fb9bde] Discussion: In part one we learned the basics to reading volumes. We practiced on two graduated cylinders, an Erlenmeyer flask, and a burette. They were pre-filled with water to random points and we took approximate measurements. Measurements were recorded along with the standard deviation. In part two we practiced taking measurements with a precise digital scale. We learned how to zero the device using the tare feature. We discovered that post-1983 pennies weighed less than pre-1982 pennies because different metals were used. In part three we used the skills learned in part two to weigh a flask with and 2004-04-30T03:02:38-04:00 http://75.150.148.189/free-essay/Lab-Introduction-to-Laboratory-Techniques-91.aspx Throughout history scientific advances have been both a means of helping and destroying society. In all of the three major scientific disciplines weapons of mass destruction have been created. In physics nuclear weapons were created, in biology viruses were created and turned into weapons, and in chemistry elements were mixed together to create poisonous gases and toxins. In modern times the most widespread uses of these types of weapons have been with chemical weapons because they are the cheapest and easiest to produce. The first large-scale usage of chemical weapons came during World War I, forty years later the Nazis used cyanide gas during WWII against Jews. The United States used Agent Orange against the Vietnamese, and later in the 1980’s the Iraqis gassed the Iranians and Kurds. In 1995 a religious cult let off a chemical bomb in a Tokyo subway, and currently the biggest fear of chemical weapons is from the possibility of their use in a terrorist attack. There are a few different types of chemical weapons. The most dangerous type of chemical weapons are nerve agents that can cause death in seconds and are odorless and tasteless. Nerve agents disrupt the functions of the nervous systems and shut down all vital body functions. The most common type are blistering agents which were commonly used in WWI and cause most organic tissue that comes in contact with the chemical to burn and blister. Other types include choking agents, blood agents, and toxins. Although some chemical weapons were developed as early as 1855 the first time they were used in battle to deliberately kill soldiers was during World War I. In 1915 the Germans launched their first chemical attack against the British. By 1918 at the end of the war almost a million people had been killed or injured by poisonous gases. The most common type of chemical weapon was mustard gas that was put on shells, which were fired at the enemy. Mustard gas is considered a blistering agent because it burns any part of the skin, lungs, or eyes that it comes in contact with. After the horrors of gas attacks in WWI the allies and axis powers refrained from using any chemical weapons during battle. During this same time, however, the largest genocide in the history of the world was taking place with the use of chemical agents. The Nazis used chemical pesticides to kill millions of Jews 2004-02-22T19:34:41-05:00 http://75.150.148.189/free-essay/Chemical-Warfare-and-Terrorism-44.aspx