Portal:Chemistry
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Welcome to the chemistry portal. Chemistry is a branch of science. Modern chemistry focuses on the study of elements of the world and the bonds between elements. Chemistry also deals with composition, structure, and properties of substances and the transformations that they undergo.The study of chemistry can help people to make new materials. In the study of matter, chemistry also investigates its interactions with energy and itself. Because of the diversity of matter, which is mostly in the form of compounds, chemists often study how atoms of different chemical elements interact to form molecules, and how molecules interact with each other.
Lua error in package.lua at line 80: module 'Module:Box-header/colours' not found. Uranium is a silvery metallic chemical element in the actinide series of the periodic table that has the symbol U and atomic number 92. The heaviest naturally occurring element, uranium is nearly twice as dense as lead and weakly radioactive. It occurs naturally in low concentrations (a few parts per million) in soil, rock and water, and is commercially extracted from uranium-bearing minerals such as uraninite (see uranium mining).In nature, uranium atoms exist as uranium-238 (99.275%), uranium-235 (0.72%), and a very small amount of uranium-234 (0.0058%). Uranium decays slowly by emitting an alpha particle. The half-life of uranium-238 is about 4.5 billion years and that of uranium-235 is 700 million years, making them useful in dating the age of the earth (see uranium-thorium dating, uranium-lead dating and uranium-uranium dating). Along with thorium and plutonium, it is one of the three fissile elements, meaning it can easily break apart to become lighter elements. This property of uranium-235 and to a lesser degree uranium-233 generates the heat needed to run nuclear reactors and provides the explosive material for nuclear weapons. Both uses rely on the ability of uranium to produce a sustained nuclear chain reaction. Depleted uranium (uranium-238) is used in kinetic energy penetrators and armor plating. Research by Enrico Fermi and others starting in 1934 led to its use as a fuel in the nuclear power industry and in the first nuclear weapon used in war (see Little Boy and Atomic bombings of Hiroshima and Nagasaki). An ensuing arms race during the Cold War between the United States and the Soviet Union produced tens of thousands of nuclear weapons that used enriched uranium and uranium-derived plutonium. The security of those weapons and their fissile material following the breakup of the Soviet Union in 1991 along with the legacy of nuclear testing and nuclear accidents is a concern for public health and safety. Lua error in package.lua at line 80: module 'Module:Box-header/colours' not found. Lua error in package.lua at line 80: module 'Module:Box-header/colours' not found. Fields of Chemistry (books)
Many chemists have an interest in the history of chemistry. Those with philosophical interests will be interested that the philosophy of chemistry has quite recently developed along a path somewhat different from the general philosophy of science. Other articles that might interest you are: There is a Wikipedia Project on the History of Science and a portal for the philosophy of science. Wikipedia:WikiProject Chemicals/Data is a collection of links and references that are useful for chemistry-related works. This includes free online chemical databases, publications, patents, computer programs, and various tools. Science is Fun University of Wisconsin–Madison Chemistry Professor Bassam Z. Shakhashiri, shares the fun of science. unit-conversion.info A good place to figure out what equals what. General Chemistry Online Clear text and comprehensive coverage of general chemistry topics by Fred Senese, Dept. of Chemistry Frostburg State University General Chemistry Demonstration at Purdue Video clips (and descriptions) of lecture demonstrations. Intota Chemistry Experts A large online listing of real-world chemistry expert biographies provides examples of the many areas of expertise and careers in chemistry. Chemistry Webercises Directory A large listing of chemistry resources maintained by Steven Murov, Emeritus Chemistry Professor Modesto Junior College. MathMol MathMol (Mathematics and Molecules) is a good starting point for those interested in the field of molecular modeling. Chemistry Educational Resources and Essential References from Wiley, the world's largest chemistry publisher ABC-Chemistry A directory of free full-text journals in chemistry, biochemistry and related subjects. The Element Song A goofy little song about all of the elements. Lua error in package.lua at line 80: module 'Module:Box-header/colours' not found. Jacobus Henricus van 't Hoff (1852-1911) was a Dutch physical and organic chemist, and recipient of the inaugural Nobel Prize for Chemistry. His first major findings accounted for the phenomenon of optical activity by assuming that the chemical bonds between carbon atoms and their neighbors were directed towards the corners of a regular tetrahedron. This three-dimensional structure perfectly accounted for the isomers found in nature (stereochemistry). He shares credit for this idea with the French chemist Joseph Le Bel, who independently came up with the same idea. He received the first Nobel Prize for his work on relating the behaviour of solutions to that displayed by gases.Companies: AstraZeneca - Bayer - BP - BASF - Bristol-Myers Squibb - Dow - DuPont - Evonik Industries - ExxonMobil - GlaxoSmithKline - The Linde Group - Mitsubishi - Monsanto - Nestlé - OSI - Shell - Sigma-Aldrich - Sasol - Total Lua error in package.lua at line 80: module 'Module:Box-header/colours' not found. Lua error in package.lua at line 80: module 'Module:Box-header/colours' not found.
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