Carbon dioxide - CO₂

Carbon dioxide is a colourless gas formed of two elements, carbon and oxygen. It is produced in the combustion of coal or hydrocarbons and breathing of humans and animals. Carbon dioxide is used in the photosynthesis where plants and cyanobacteria “breathe”.

Carbon dioxide is a gas that can be used in many different applications. It is for example used in the chemical industry for controlling reactor temperatures, as well as in the food and beverage industry. CO₂ is also used as an alternative to sulphuric acid for pH balance control.

The main hazards of carbon dioxide are inhalation and high pressure. 

Properties

Molecular weight 44.01 g/mol.

Gaseous phase Gas density (1.013 bar at sublimation point): 2.813 kg/m³
 Gas density (1.013 bar and 15 °C (59 °F)): 1.8714 kg/m³

Solid phase  Melting point: 56.57 °C

Liquid phase Boiling point (sublimation): -78.45 °C
 Liquid density (at -20 °C (or -4 °F) and 19.7 bar): 1256.74 kg/m³

Critical point Critical temperature: 30.98 °C
 Critical pressure: 73.77 bar
 Critical density: 467.6 kg/m³