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Oxygen gas is the second most common component of the Earth's atmosphere, taking up 20.8% of its volume and 23.1% of its mass (some 10 15 tonnes). [19] [70] [d] Earth is unusual among the planets of the Solar System in having such a high concentration of oxygen gas in its atmosphere: Mars (with 0.1% O 2 by volume) and Venus have much less. The O
Triatomic oxygen (ozone, O 3) is a very reactive allotrope of oxygen that is a pale blue gas at standard temperature and pressure. Liquid and solid O 3 have a deeper blue color than ordinary O 2, and they are unstable and explosive. [5] [6] In its gas phase, ozone is destructive to materials like rubber and fabric and is damaging to lung tissue ...
Oxygen began building up in the prebiotic atmosphere at approximately 1.85 Ga during the Neoarchean-Paleoproterozoic boundary, a paleogeological event known as the Great Oxygenation Event (GOE). At current rates of primary production, today's concentration of oxygen could be produced by photosynthetic organisms in 2,000 years. [4]
Solid oxygen forms at normal atmospheric pressure at a temperature below 54.36 K (−218.79 °C, −361.82 °F). Solid oxygen O 2 , like liquid oxygen , is a clear substance with a light sky-blue color caused by absorption in the red part of the visible light spectrum.
The only chemical elements that form stable homonuclear diatomic molecules at standard temperature and pressure (STP) (or at typical laboratory conditions of 1 bar and 25 °C) are the gases hydrogen (H 2), nitrogen (N 2), oxygen (O 2), fluorine (F 2), and chlorine (Cl 2), and the liquid bromine (Br 2). [1]
The Great Oxidation Event (GOE) or Great Oxygenation Event, also called the Oxygen Catastrophe, Oxygen Revolution, Oxygen Crisis or Oxygen Holocaust, [2] was a time interval during the Earth's Paleoproterozoic era when the Earth's atmosphere and shallow seas first experienced a rise in the concentration of free oxygen. [3]
Liquid oxygen has a clear cyan color and is strongly paramagnetic: it can be suspended between the poles of a powerful horseshoe magnet. [2] Liquid oxygen has a density of 1.141 kg/L (1.141 g/ml), slightly denser than liquid water, and is cryogenic with a freezing point of 54.36 K (−218.79 °C; −361.82 °F) and a boiling point of 90.19 K (−182.96 °C; −297.33 °F) at 1 bar (14.5 psi).
A breathing gas is a mixture of gaseous chemical elements and compounds used for respiration. Air is the most common and only natural breathing gas. Other mixtures of gases, or pure oxygen, are also used in breathing equipment and enclosed habitats such as scuba equipment, surface supplied diving equipment, recompression chambers, high-altitude mountaineering, high-flying aircraft, submarines ...