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Author: langbot
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English[en]
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as well as with other compounds. Oxygen is Earth's most abundant element, and after hydrogen and helium, it is the third-most abundant element in the universe. At standard temperature and pressure, two atoms of the element bind to form dioxygen, a colorless and odorless diatomic gas with the formula O 2. Diatomic oxygen gas currently constitutes 20.95% of the Earth's atmosphere, though this has changed considerably over long periods of time. Oxygen makes up almost half of the Earth's crust in the form of oxides.[3] Dioxygen provides most of the chemical energy released in combustion[4] and aerobic cellular respiration,[5] and many major classes of organic molecules in living organisms contain oxygen atoms, such as proteins, nucleic acids, carbohydrates, and fats, as do the major constituent inorganic compounds of animal shells, teeth, and bone. Most of the mass of living organisms is oxygen as a component of water, the major constituent of lifeforms. Oxygen is continuously replenished in Earth's atmosphere by photosynthesis, which uses the energy of sunlight to produce oxygen from water and carbon dioxide. Oxygen is too chemically reactive to remain a free element in air without being continuously replenished by the photosynthetic action of living organisms. Another form (allotrope) of oxygen, ozone (O 3), strongly absorbs ultraviolet UVB radiation and the high-altitude ozone layer helps protect the biosphere from ultraviolet radiation. However, ozone present at the surface is a byproduct of smog and thus a pollutant. Oxygen was isolated by Michael Sendivogius before 1604, but it is commonly believed that the element was discovered independently by Carl Wilhelm Scheele, in Uppsala, in 1773 or earlier, and Joseph Priestley in Wiltshire, in 1774. Priority is often given for Priestley because his work was published first. Priestley, however, called oxygen "dephlogisticated air", and did not recognize it as a chemical element. The name oxygen was coined in 1777 by Antoine Lavoisier, who first recognized oxygen as a chemical element and correctly characterized the role it plays in combustion. Common uses of oxygen include production of steel, plastics and textiles, brazing, welding and cutting of steels and other metals, rocket propellant, oxygen therapy, and life support systems in aircraft, submarines, spaceflight and diving.
Cornish[kw]
Elven gymyk yw oksyjen, niver 8 y'n Vosen Beriodek. Y furvell gymyk yw O. An hanow a dheu dhyworth an geryow Greka oxy genes, ow styrya furvya trenken. Oksyjen yw an elven tressa moyha pals y'n Ollvys, wosa hidrojen ha heliom. Y'n Kevreyth Howlek, anusadow yw an Norvys drefen bos kemmys oksyjen y'n ayrgylgh (arwodh sur a vewnans, drefen bos furvyes gans lughwrians). Essensek yw oksyjen drefen y vos rann a DNAha kesstoffow erel posek dhe vewonieth. Yma edhomm dhe pub eneval a oksyjen rag anella. Nans yw a-dro dhe 2.4 bilvil bledhen an nivel oksyjen y'n ayrgylgh a dhallathas sevel y'n Hwarvos Oksidysans Meur. Eghennow nowydh a usyas lughwrians dhe askorra oksyjen. An oksyjen o gwenon dhe'n cyanobakteria hag a vewa kyns. Ny yll den anella pan vo le ages 17% oksyjen y'n ayrgylgh. Mes re oksyjen yw peryllus ynwedh, yn arbennek dhe sedhoryon downvor, neb a yll kavos the bends. Joseph Priestley (1733-1804) a veu an kynsa dhe dhiskrifa oksyjen yn mis Est 1774. Ev a fogellas howlsplann war verkurik oksid (HgO), ha kuntel an gass hag a veu askorrys. Carl Wilhelm Scheele (1742-1786), kymygydh a Sweden, a wrug devnydhya an unn method diw vledhen kyns henna, mes ny skrifas derivas. Yn mis Gwynngala 1774 ev a skrifas lyther dhe Antoine Lavoisier (1743-94) yn Pow Frynk a-dro dhe'y dhiskudhyans. Ny leveris Lavoisier ev dhe dhegemeres an lyther. Priestley a vysytyas Lavoisier yn mis Hedra 1774, ha ny leveris Lavoisier a-dro dhe henna hwath. Mes Lavoisier a gonvedhas diskudhyans oksygen dhe dhisprevi tybieth phlogiston. Lavoisier a brovyas an hanow oxygene rag an elven. Askorrys yw 100 milvil tonnas a oksyjen dhyworth an ayr pub bledhen, po dhyworth ayr linyel po devnydhya ridrow zeolit dhe sugna'n nitrojen dhyworth an ayr. Usys yw an brassa rann a'n oksyjen dhe wul dur (55%) po y'n diwysyans kymyk (25%). Usys yw mynsow le yn klavjiow, dyghtya dowr, fusennow ha treghi alkenyow. An diwysyans kymyk a dhasober oksyjen gans ethylen dhe wul ethylen oksid, hag yn y dro dhe wul lin gorthrew, polyester ha gwiasow dillas. Monow silikon-oksyjen a gomprehend an brassa rann a groghen an Norvys, war-barth oksidow elvennow erel. Oksyjen y'n ayrgylgh ughel a wari rann bosek yn y furv ozon (O3). An ozon a wra sugna dewynnyans ugh-violet, ow kwitha enep an Norvys rag an dewynnyans peryllus ma. Klorofluorokarbonow o kudyn meur dhe'n Nivel Ozon, mes lettyes ens gans an Protokol Montreal yn 1987. Poos atomek yw 15.99, y boynt teudhi yw -218°C ha'y boynt bryjyon yw -183°C. Y dhosedh yw 1.43 gramm an liter. Gass diliw, anvlasus yw oksyjen. Glas yw liw lin oksyjen.