OCR A-Level Physics/The Newtonian World/Ideal gases

Mole: The SI unit of amount of substance. Each mole contains   elementary entities Assumptions: Gas contains a very large number of molecules which are in continuous random motion Volume of molecules is negligible compared to volume of container Collisions between molecules and the container are perfectly elastic Time of collision is negligible compared to time between collisions Electrostatic forces are negligible except during collisions How a gas exerts pressure on walls of container: Particle collides with container wall and changes momentum Force of wall on particle is equal to rate of change of particle's momentum (N2L) Force of particle on wall is same magnitude but opposite direction (N3L) Pressure = Sum of all particle forces / area of wall