Molar Mass of Dinitrogen
| Value | 0.028014 kg/mol |
| Status | Measured: ± 0.000002 kg/mol (0.000071 relative) |
| Source | IUPAC |
| Categories | Chemistry |
| gram per mole | 28.014 g/mol |
| kilogram per kilomole | 28.014 kg/kmol |
| milligram per millimole | 28.014 mg/mmol |
| pound per pound-mole | 28.014 lb/lb-mol |
| dalton (as molar mass) | 28.014 Da |
| kilogram per mole | 0.028014 kg/mol |
| kilodalton (as molar mass) | 0.028014 kDa |
Learning zone
Nitrogen makes up 78.08 % of dry air by volume and at 28.014 g/mol it is what sets air's effective molar mass of 28.96 g/mol, the number behind the specific gas constant of 287.05 J/(kg·K) used throughout HVAC and aerodynamics. Anything lighter than 28.96 g/mol rises in air and anything heavier sinks, which is the entire safety logic for hydrogen (2.016), helium (4.003), methane (16.043) and propane (44.10).
The triple bond that makes N₂ so unreactive — 945 kJ/mol, one of the strongest in chemistry — is why the atmosphere is four-fifths fertiliser that plants cannot touch. Breaking it at scale took the Haber–Bosch process of 1909–13, which now fixes roughly 150 million tonnes of nitrogen a year and, by most estimates, feeds about half the people alive. Every tonne of that ammonia is metered by this molar mass.