Oxygen / O₂

Oxygen

Gaz Identification

Other denomination
Dioxygen
CAS Registry Number
7782-44-7
SCBA type
ARI

Chemical properties

Molecular formula
O₂
Molecular mass
32 g/mol

Physical properties

Boiling point
-183 °C
Autoignition temperature
-
Gas/Vapour density
1,43
IP
12,1 eV

Inflammability limit

LFL
-
UFL
-

Exposition limit

TLV-TWA
-
TLV-STEL
-

Oxygen : Description and utilisation

Description

Dioxygen, commonly referred to as oxygen or molecular oxygen by popularisation, is a gaseous substance under normal temperature and pressure conditions. It was discovered on 1 August 1774 by the English chemist Joseph Priestley, and given the name "oxygen" by the French chemist Antoine Lavoisier in 1778.
Comprising 20.95% of the Earth's atmosphere in terms of volume (23.2% in terms of mass), dioxygen is an essential gas for the majority of current life forms, to which it provides the fuel required for cells to function (cellular respiration). In the aquatic environment, dissolved dioxygen is also required for the survival of a large amount of species. It plays a role in redox reactions, particularly in relation to combustion, corrosion and respiration.
It is a colourless gas at ambient temperature and pressure; liquefied gas: colourless-to-blue liquid.

USE
  • oxidising agent
  • combustion agent

Oxygen : Danger and care

GHS hazard statements

H270 - May cause or intensify fire; oxidiser.
H280 - Contains gas under pressure; may explode if heated.

GHS precautionary statements

P244 - Keep reduction valves free from grease and oil.

SGH04 : Gaz sous pression
SGH03 : Comburant