State Dalton's law of partial pressures and Graham's law of diffusion.

Dalton's law states that the total pressure of a mixture of non-reacting gases equals the sum of the partial pressures each would exert alone in the same volume. Graham's law states that at constant temperature and pressure the rate of diffusion of a gas is inversely proportional to the square root of its density.

No citable source has been recorded for this record. Treat it as practice material, not as fact.

Explanation

Graham's law is why lighter gases diffuse faster.