Gas Density:

The density of a gas can be defined in three ways, precisely after the manner of liquids. Mass density is defined in terms of the number of kilograms per meter cubed (kg/m³) that a sample of gas have. The weight density is stated in newtons per meter cubed (N/m³) and is equivalent to the mass density multiplied by the acceleration in meters per second squared (m/s²) to which the sample is subjected. The particle density is stated as the number of moles of atoms per meter cubed (mol/m³) in a parcel of gas, here

1 mol ≈ 6.02 x 10²³