You will need
  • the density of air molar mass of air quantity of air, the volume occupied by the air
Let us known the volume V, which takes the air. Then, by the well-known formula m = p*V, where p is the density of air, we can find the mass of air in this volume.
Density of air depends on its temperature. The density of dry air is calculated using the Clapeyron equation for an ideal gas according to the formula: p = P/(R*T) where P is the absolute pressure, T is the absolute temperature in Kelvin and R is the specific gas constant for dry air (R = 287,058 j/(kg*K)).
At sea level at a temperature of 0oC the density of air equal to at 1.2920 kg/(m^3).
If we know the amount of air, its mass can be found by the formula: m = m*V, where V is the amount of substance in moles, and M is the molar mass of air. Average relative molar mass of air equal to of 28.98 g/mol. Thus, substituting it in the formula, you get a lot of air in grams.