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).
An older method is based on chemical reactions barium oxide method. It is uneconomical due to high energy costs. For barium oxide is heated under air at 500 degrees C., the barium forms. When heated to 700 degrees C recorded earlier O2 is released by thermolysis again. Prior to development of Linde process, this method was the only way to pure O2 present.
From the Stone Age to Middle Ages, the fire to humans was a phenomenon which has been accepted as a gift from heaven. About the nature of fire caused by the different conceptions natural philosophers of antiquity to alchemist. The fire was seen as an essential ingredient of Earth. In 17th century the notion of a "light mysterious substance" was born. This phlogiston would escape from the burning fuel, heat was understood as a substance. The German-Swedish chemist Carl Wilhelm Scheele conducted experiments. When heating manganese dioxide (manganese dioxide) or potassium permanganate with concentrated sulfuric acid (vitriol) he gave a colorless gas.
Even in so-called main sequence stars like the sun plays a role in energy oxygen. In CNO cycle (CNO cycle) represents O2 is an intermediate of nuclear reaction in which proton capture by a 12C nucleus, which acts as a catalyst, a 4He nucleus (alpha particle) is produced. In extremely heavy stars occurs in late stage of their development to O2 burning, in which the O2 is used as nuclear fuel for reactions that lead to construction of even heavier nuclei.
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.
Since these orbitals are completely filled with electrons, they do not contribute to binding. From the 2p orbitals are a total of six molecular orbitals with different energy level. The orbitals have this same energy. Electrons are distributed in molecular orbitals, it comes to following breakdown of eight p-electrons. These two valence electrons determine the properties of O2 molecule. O2 has allowed a total of three and energetically accessible quantum states for the distribution of these electrons.
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).
The most common stable oxygen isotope 16O (99.76%), in addition still comes 18O (0.20%) and 17O (0.037%) before. In addition to the stable oxygen isotopes are still a total of 13 unstable, radioactive nuclides from 12O to 28O are known which are artificially produced. Their half lives often are only milliseconds to seconds, with two minutes 15O this case has the longest half-life, and is frequently used in positron emission tomography.
An older method is based on chemical reactions barium oxide method. It is uneconomical due to high energy costs. For barium oxide is heated under air at 500 degrees C., the barium forms. When heated to 700 degrees C recorded earlier O2 is released by thermolysis again. Prior to development of Linde process, this method was the only way to pure O2 present.
From the Stone Age to Middle Ages, the fire to humans was a phenomenon which has been accepted as a gift from heaven. About the nature of fire caused by the different conceptions natural philosophers of antiquity to alchemist. The fire was seen as an essential ingredient of Earth. In 17th century the notion of a "light mysterious substance" was born. This phlogiston would escape from the burning fuel, heat was understood as a substance. The German-Swedish chemist Carl Wilhelm Scheele conducted experiments. When heating manganese dioxide (manganese dioxide) or potassium permanganate with concentrated sulfuric acid (vitriol) he gave a colorless gas.
Even in so-called main sequence stars like the sun plays a role in energy oxygen. In CNO cycle (CNO cycle) represents O2 is an intermediate of nuclear reaction in which proton capture by a 12C nucleus, which acts as a catalyst, a 4He nucleus (alpha particle) is produced. In extremely heavy stars occurs in late stage of their development to O2 burning, in which the O2 is used as nuclear fuel for reactions that lead to construction of even heavier nuclei.
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.
Since these orbitals are completely filled with electrons, they do not contribute to binding. From the 2p orbitals are a total of six molecular orbitals with different energy level. The orbitals have this same energy. Electrons are distributed in molecular orbitals, it comes to following breakdown of eight p-electrons. These two valence electrons determine the properties of O2 molecule. O2 has allowed a total of three and energetically accessible quantum states for the distribution of these electrons.
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).
The most common stable oxygen isotope 16O (99.76%), in addition still comes 18O (0.20%) and 17O (0.037%) before. In addition to the stable oxygen isotopes are still a total of 13 unstable, radioactive nuclides from 12O to 28O are known which are artificially produced. Their half lives often are only milliseconds to seconds, with two minutes 15O this case has the longest half-life, and is frequently used in positron emission tomography.
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