Oxygen represents an element of the 16th subgroup of the second period of Mendeleev's system. It is chemically active nonmetal rather light. Under so-called normal conditions this simple substance consisting of couple of atoms of oxygen. In a liquid phase gas has light blue color. Solid oxygen takes a form of light blue crystals.
Properties of oxygen
Oxygen represents the gas which does not have color, taste and a smell. It is heavier than air. Oxygen is necessary for breath. This gas does not burn, but sustains combustion. In oxygen quickly and without the rest very many substances, including metals burn down.
Free oxygen makes almost 21% of air. Generally oxygen contains in the mass of earth crust and in planet waters in the connected state, in the form of chemical compounds. This gas is emitted by plants: it is formed by means of photosynthesis of carbon dioxide.
When some substance connects to oxygen, this process is called oxidation. The new substance arising at the same time is called oxide or oxide. At such processes heat is generated. Oxidation can go with a different speed: very quickly or extremely slowly.
If at oxide oxygen is selected, it is about restoration reaction. Its implementation requires heat. By means of restoration receive many metals from ores.
Oxygen is widely applied in industrial production: when welding, cutting metals, in production of steel, as a divider of concrete weight and filler.
Ozone
So-called allotropic forms of oxygen are known. Ozone belongs to them. It has a specific smell. Its molecule consists of three atoms of oxygen. Under usual conditions it is the gas having a bluish shade.
Many remember how air after a strong thunderstorm smells. Such fresh aroma is formed when passing through the atmosphere of electric charges. This smell – distinctive feature of ozone. Its name just also comes from the Greek word "odorous".
Ozone represents active oxygen. It is two and a half times heavier than usual oxygen. The molecule of ozone does not differ in stability. Under normal conditions for a short time ozone turns into oxygen known to all. At the same time heat is generated. Ozone is capable to react much quicker with other substances, than oxygen. The ability of ozone to be active oxidizer and to join double communications in chemical reactions is known since 1850.
Near the surface of the planet this gas is formed at the time of lightning stroke. In vitro ozone turns out during the operation of the x-ray equipment. This gas effectively kills bacteria. It is widely applied to purification of air in rooms and by water disinfectings. In medical practice ozone is used for treatment of infections, tuberculosis, hepatitis and some forms of pneumonia.