1. Gas pressure and the ideal gas law
Assume specular collisions*
Change in momentum:
*Bold assumption – but more general calculation gives same result.

2. Molecular Flux
Element of area on the wall of the container where molecules exert a pressure due to their change in momentum upon bouncing from the wall. In time dt , molecules traveling at angle  will each sweep out a volume vdtcosdA.

3. Gas pressure and the ideal gas law
Kinetic theory provides a natural interpretation of the absolute temperature of a dilute gas. Namely, the temperature is proportional to the mean kinetic energy (e ) of the gas molecules.
The mean kinetic energy is independent of pressure, volume, and the molecular species, i.e. it is the same for all molecules.