Oxygen - O2
Oxygen is, after hydrogen and helium, the most common element in the universe. Oxygen is produced in the photosynthesis, when plants and cyanobacteria build up their cell mass. It was discovered in 1774 by the scientist Joseph Priestley.
Oxygen is a gas with many applications. It is, for example, used in the chemical industry, metal industry, and the food and beverage industry, where it is used to oxygenate fish-breeding tanks among other things.
The major hazards of oxygen are flammability and high pressure.
Properties
Molecular weight 31.999 g/mol.
Gaseous phase Gas density: (1.013 bar at boiling point): 4.4681 kg/m3
Gas density: (1.013 bar and 15 °C (59 °F)): 1.354 kg/m3
Solid phase Melting point: -218.78 °C
Liquid phase Boiling point: -182.96 °C
Liquid density: (1.013 bar at boiling point): 1141.2 kg/m3
Critical point Critical temperature: 118.57 °C
Critical pressure: 50.43 bar
Critical density: 436.14 kg/m3