How can we determine the density of air?

Density ρ of a liquid in g/L gives the mass in g of one litre of that liquid.

Example:
The density of carbon dioxide is 1.77 g/L , so the mass of one litre of carbon dioxide is 1.77 g . ✅

Density ρ is the ratio of mass m to volume V.

To determine the density ρ of air, we need:

— a balance to measure mass

and
— a graduated container (a cylinder) or a container of known capacity (a one-litre bottle).

Calculation of the mass of one litre of air:
m₁ = 453.7 ± 0.1 g
m₂ = 452.7 ± 0.1 g

m_{1 L of air} = m₁ − m₂
m_{1 L of air} = 453.7 − 452.7
m_{1 L of air} = 1.0 g ± 0.2 g 🎯

The mass of one litre of air is 1.0 g to within 0.2 g.
The density ρ of air is 1.0 g/L.

Calculation of the mass of one litre of air:
m₁ = 356.2 ± 0.1 g
m₂ = 355.2 ± 0.1 g

m_{1 L of air} = m₁ − m₂
m_{1 L of air} = 356.2 − 355.2
m_{1 L of air} = 1.0 g ± 0.2 g

The mass of one litre of air is 1.0 g to within 0.2 g.
The density ρ of air is 1.0 g/L.

The density ρ of air is 1.2 g/L at 20 °C.

Note:
The density of air depends on temperature and pressure.

For a given pressure, when temperature increases, the density of air decreases.

For a given temperature, when pressure increases, the density of air increases. 🌡️➡️📉 / ⬆️🧪➡️📈