Density, molecular mass and chemical formula of various gases including air, nitrogen (N2), helium (He), carbon dioxide (CO2) and Methane (CH4) at 25 °C and under 100 kPa pressure are given in the following gas density table.
Gas density is the ratio of its mass to volume, and gases occupy their entire container, so its density is the mass of the gas divided by the containers volume.
Note: ** Or saturation pressure if it is less than 100 kPa.
The density of gas is calculated with an alternative form of the ideal gas law. This formula is an expression of the ideal gas law in terms of density.
ρ = mP/nRT = MP/RT
where P is the gas pressure, n is mol of gas particles, R is the ideal gas constant, T is the temperature of gas, ρ is the density of gas, m is the mass and M is the molar mass of gas.