Propane - C3H8

Propane is a colourless and flammable gas. It occurs in natural gas, camping gas, and motor gas. 
It is also used to calibrate environmental emissions monitoring. 

The major hazard of propane is fire. 

Properties

Molecular weight 44.096 g/mol

Gaseous phase Gas density (1.013 bar at boiling point): 2.417 kg/m3
 Gas density (1.013 bar and 15 °C (59 °F)): 1.8988 kg/m3

Solid phase Melting point: 187.68 °C

Liquid phase  Boiling point (1.013 bar): -42.11 °C
 Liquid density (1.013 bar at boiling point): 580.99 kg/m3

Critical point  Critical temperature: 96.74 °C
 Critical pressure: 42.51 bar
 Critical density: 220.48 kg/m3