Density of Gases
Density, molecular mass, and chemical formula for common gases—air, nitrogen (N2), helium (He), carbon dioxide (CO2), methane (CH4), and others—at 25 °C and 100 kPa are listed below. Gas density is mass per unit volume; for ideal gases it can be calculated from the ideal gas law as ρ = MP/(RT).
Density of Gases at 25 °C, 100 kPa **
| Gas |
Chemical Formula |
Molecular Mass |
Density kg/m³ |
| Steam | H2O | 18.015 | 0.0231 |
|---|
| Acetylene | C2H2 | 26.038 | 1.05 |
|---|
| Air | — | 28.97 | 1.169 |
|---|
| Ammonia | NH3 | 17.031 | 0.694 |
|---|
| Argon | Ar | 39.948 | 1.613 |
|---|
| Butane | C4H10 | 58.124 | 2.407 |
|---|
| Carbon monoxide | CO | 28.01 | 1.13 |
|---|
| Carbon dioxide | CO2 | 44.01 | 1.775 |
|---|
| Ethane | C2H6 | 30.07 | 1.222 |
|---|
| Ethanol | C2H5OH | 46.069 | 1.883 |
|---|
| Ethylene | C2H4 | 28.054 | 1.138 |
|---|
| Helium | He | 4.003 | 0.1615 |
|---|
| Hydrogen | H2 | 2.016 | 0.0813 |
|---|
| Methane | CH4 | 16.043 | 0.648 |
|---|
| Methanol | CH3OH | 32.042 | 1.31 |
|---|
| Neon | Ne | 20.183 | 0.814 |
|---|
| Nitric oxide | NO | 30.006 | 1.21 |
|---|
| Nitrogen | N2 | 28.013 | 1.13 |
|---|
| Nitrous oxide | N2O | 44.013 | 1.775 |
|---|
| n-Octane | C8H18 | 114.23 | 0.092 |
|---|
| Oxygen | O2 | 31.999 | 1.292 |
|---|
| Propane | C3H8 | 44.094 | 1.808 |
|---|
| R-12 | CCl2F2 | 120.914 | 4.98 |
|---|
| R-22 | CHClF2 | 86.469 | 3.54 |
|---|
| R-134a | CF3CH2F | 102.03 | 4.20 |
|---|
| Sulfur dioxide | SO2 | 64.059 | 2.618 |
|---|
| Sulfur trioxide | SO3 | 80.053 | 3.272 |
|---|
Note: **Or saturation pressure if less than 100 kPa.
Density of Gas Formula
The ideal gas expression for density is ρ = MP/(RT), where M is molar mass (kg/mol), P is absolute pressure (Pa), R is the universal gas constant (8.314462618 J·mol⁻¹·K⁻¹), and T is absolute temperature (K).
Related Topics
Reference