Vapour_density
Vapour density is the density of a vapour in relation to that of hydrogen. It may be defined as mass of a certain volume of a substance divided by mass of same volume of hydrogen.
- vapour density = mass of n molecules of gas / mass of n molecules of hydrogen gas .
- vapour density = molar mass of gas / molar mass of H2
- vapour density = molar mass of gas / 2.01568
- vapour density = 1⁄2 × molar mass
(and thus: molar mass = ~2 × vapour density) For example, vapour density of mixture of NO2 and N2O4 is 38.3. Vapour density is a dimensionless quantity.