Portal:Chemistry
Introduction
Chemistry is the scientific study of the properties and behavior of matter. It is a physical science within the natural sciences that studies the chemical elements that make up matter and compounds made of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they undergo during reactions with other substances. Chemistry also addresses the nature of chemical bonds in chemical compounds.
In the scope of its subject, chemistry occupies an intermediate position between physics and biology. It is sometimes called the central science because it provides a foundation for understanding both basic and applied scientific disciplines at a fundamental level. For example, chemistry explains aspects of plant growth (botany), the formation of igneous rocks (geology), how atmospheric ozone is formed and how environmental pollutants are degraded (ecology), the properties of the soil on the Moon (cosmochemistry), how medications work (pharmacology), and how to collect DNA evidence at a crime scene (forensics).
Chemistry has existed under various names since ancient times. It has evolved, and now chemistry encompasses various areas of specialisation, or subdisciplines, that continue to increase in number and interrelate to create further interdisciplinary fields of study. The applications of various fields of chemistry are used frequently for economic purposes in the chemical industry. (Full article...)
Selected article
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 dissolution of the Soviet Union in 1991 along with the legacy of nuclear testing and nuclear accidents is a concern for public health and safety.
Subcategories
- Analytical chemistry: Chromatography, Spectroscopy
- Biochemistry: Molecular biology
- Crystal Chemistry
- Environmental chemistry: Geochemistry
- Inorganic chemistry: Inorganic reactions
- Materials science: Nanotechnology, Glass, Ceramics
- Medicinal chemistry
- Metallurgy
- Nuclear chemistry
- Organic chemistry: Functional groups, Organic compounds, Organic reactions
- Organometallic chemistry
- Pharmacy
- Physical chemistry: Electrochemistry, Quantum chemistry
- Polymer chemistry
- Supramolecular chemistry
- Theoretical chemistry: Computational chemistry
History and Philosophy of Chemistry
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.
Chemistry Resources
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.
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.
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.
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.
Selected image
Selected biography
Techniques used by chemists
Equipment used by chemists
Chemistry in society
Chemistry in industry
Companies: AstraZeneca - Bayer - BP - BASF - Bristol-Myers Squibb - DowDuPont - Evonik Industries - ExxonMobil - Linde plc - Mitsubishi - Monsanto - Nestlé - OSI - Shell - Sigma-Aldrich - Sasol - Total - GlaxoSmithKline - Teva
WikiProjects
Topics
Periodic Table
| Group | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | |
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| Hydrogen & alkali metals |
Alkaline earth metals | Triels | Tetrels | Pnictogens | Chalcogens | Halogens | Noble gases | ||||||||||||
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- Ca: 40.078 — Abridged value (uncertainty omitted here)[2]
- Po: [209] — mass number of the most stable isotope
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Sources
- ^ Meija, Juris; et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure and Applied Chemistry. 88 (3): 265–91. doi:10.1515/pac-2015-0305.
- ^ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.
