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
Helium is the second most abundant element in the known Universe and second lightest element in the periodic table. In the modern Universe almost all new helium is created as a result of the nuclear fusion of hydrogen in stars. On Earth it is created by the radioactive decay of much heavier elements (alpha particles are helium-4 nuclei produced by alpha-decay). After its creation, part of it is trapped with natural gas in concentrations up to 7% by volume. It is extracted from the natural gas by a low temperature separation process called fractional distillation.
In 1868 the French astronomer Pierre Janssen first detected helium as an unknown yellow spectral line signature in light from a solar eclipse. (The word helium comes from ancient Greek ἥλιος which is, surprisingly, cognate with the English sun.) Since then large reserves of helium have been found in the natural gas fields of the United States, which is by far the largest supplier of the gas. Helium is used in cryogenics, in deep-sea breathing systems, to cool superconducting magnets, in helium dating, for inflating balloons, for providing lift in airships and as a protective gas for many industrial uses (such as arc welding and growing silicon wafers). Inhaling a small volume of the gas temporarily changes the quality of one's voice.
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
Related portals
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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.
