Elemental oxygen occurs predominantly in form of a covalent homodimer on, that is a compound of two O2 atoms and having the empirical formula O2, referred to as molecular oxygen or dioxygen. There is a colorless and odorless gas that is contained in air to 20.942%. It is involved in many combustion and corrosion processes (oxygen for energy).
Almost all living organisms need O2 to live (typically give plants during photosynthesis but more O2 from than they consume). You see him mostly by breathing in air, or by absorption of water (dissolved oxygen). In high concentrations, however, it is toxic to most living things.The metastable, high-energy and reactive allotrope of three O2 atoms (O3) is called ozone. Atomic oxygen, ie O2 in form of free, single O2 atoms, is stable before only under extreme conditions, such as in vacuum of space or in hot stellar atmospheres. However, it has a significant meaning as a reactive intermediate in many reactions of atmospheric chemistry.
Oxygen is not created in primordial nucleosynthesis, but is produced in relatively large amounts in giant stars by helium burning. It is first formed from three helium nuclei 12C (Triple-alpha process), which subsequently merged with another helium nucleus to 16O. 18O is formed by fusion of 4He with a 14N nucleus.
O2 is slightly soluble in water. The solubility depends on the pressure and the temperature. It increases with decreasing temperature and increasing pressure. At 0 degrees C and an O2 partial pressure of air of 212 hPa dissolve in pure water 14.16 mg / l oxygen. In oxygen-gas discharge Spectrum, the molecular orbitals of O2 are stimulated to emit light. The operating conditions are a pressure of 5-10 mbar, a high voltage of 1.8 kV, a current of 18 mA and a frequency of 35 kHz. During the recombination of ionized gas molecules, the characteristic color spectrum is emitted. In this case, a small part, caused reversibly formed by the supply of energy ozone.
With the discovery of O2 its meaning was not clear during combustion. The Frenchman Antoine Lavoisier found in his experiments that during combustion does not escape phlogiston, but O2 is bound. By weighing it demonstrated that a substance after combustion was not easier but harder. This was caused by the additional weight of ingested during the combustion process oxygen.
For O2 recovery after Claude process air by means of compressors to 5-6 bar is compressed, cooled and then removed by first filter of carbon dioxide, humidity, and other gases. The compressed air is cooled by flowing past gases from the process to a temperature near the boiling point. It is then expanded in turbines. A portion of energy used for compression can again be recovered. This is the method -. In contrast to Linde process, in which no energy is recovered - a lot more efficient.
O2 is the most abundant and widespread element on earth. It occurs both in atmosphere and in lithosphere, hydrosphere and biosphere. O2 has a mass fraction of 50.5% of earth's crust (up to 16 km depth, including hydro and atmosphere). In air, his mass fraction is 23,16% (by volume: 20.95%), the water 88.8% (the sea water but only 86%, since there large amounts salts, eg. As sodium chloride are dissolved).
Usually takes O2 in its compounds, and in earth before. In earth's crust almost all minerals and rocks are so well oxygenated water next. Among the most important minerals include oxygen-containing silicates such as feldspars, mica and Olivine, carbonates such as calcium carbonate in limestone and oxides such as silica as quartz.
Almost all living organisms need O2 to live (typically give plants during photosynthesis but more O2 from than they consume). You see him mostly by breathing in air, or by absorption of water (dissolved oxygen). In high concentrations, however, it is toxic to most living things.The metastable, high-energy and reactive allotrope of three O2 atoms (O3) is called ozone. Atomic oxygen, ie O2 in form of free, single O2 atoms, is stable before only under extreme conditions, such as in vacuum of space or in hot stellar atmospheres. However, it has a significant meaning as a reactive intermediate in many reactions of atmospheric chemistry.
Oxygen is not created in primordial nucleosynthesis, but is produced in relatively large amounts in giant stars by helium burning. It is first formed from three helium nuclei 12C (Triple-alpha process), which subsequently merged with another helium nucleus to 16O. 18O is formed by fusion of 4He with a 14N nucleus.
O2 is slightly soluble in water. The solubility depends on the pressure and the temperature. It increases with decreasing temperature and increasing pressure. At 0 degrees C and an O2 partial pressure of air of 212 hPa dissolve in pure water 14.16 mg / l oxygen. In oxygen-gas discharge Spectrum, the molecular orbitals of O2 are stimulated to emit light. The operating conditions are a pressure of 5-10 mbar, a high voltage of 1.8 kV, a current of 18 mA and a frequency of 35 kHz. During the recombination of ionized gas molecules, the characteristic color spectrum is emitted. In this case, a small part, caused reversibly formed by the supply of energy ozone.
With the discovery of O2 its meaning was not clear during combustion. The Frenchman Antoine Lavoisier found in his experiments that during combustion does not escape phlogiston, but O2 is bound. By weighing it demonstrated that a substance after combustion was not easier but harder. This was caused by the additional weight of ingested during the combustion process oxygen.
For O2 recovery after Claude process air by means of compressors to 5-6 bar is compressed, cooled and then removed by first filter of carbon dioxide, humidity, and other gases. The compressed air is cooled by flowing past gases from the process to a temperature near the boiling point. It is then expanded in turbines. A portion of energy used for compression can again be recovered. This is the method -. In contrast to Linde process, in which no energy is recovered - a lot more efficient.
O2 is the most abundant and widespread element on earth. It occurs both in atmosphere and in lithosphere, hydrosphere and biosphere. O2 has a mass fraction of 50.5% of earth's crust (up to 16 km depth, including hydro and atmosphere). In air, his mass fraction is 23,16% (by volume: 20.95%), the water 88.8% (the sea water but only 86%, since there large amounts salts, eg. As sodium chloride are dissolved).
Usually takes O2 in its compounds, and in earth before. In earth's crust almost all minerals and rocks are so well oxygenated water next. Among the most important minerals include oxygen-containing silicates such as feldspars, mica and Olivine, carbonates such as calcium carbonate in limestone and oxides such as silica as quartz.
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