Questions about the assumptions, equations, and properties of gases derived from kinetic theory. For questions pertaining to rates of reactions, please use the kinetics tag instead.

The kinetic theory of gases describes a gas as a collection of particles, in constant, random, classical motion.

From this description alone, many thermodynamic properties of ideal gases can be calculated. For example, the pressure is considered to arise from the force exerted by particles colliding against the walls of the container, and one can use classical mechanics to calculate that p = Nm<v2>/3​V. In conjunction with the equipartition theorem, which states that the average kinetic energy of a particle is given by m<v2>/2 = 3​kT/2, this leads to the ideal gas law pV = NkT.

A major result deriving from kinetic theory is the Maxwell-Boltzmann distribution for gases. This distribution is fundamental to understanding how activation energies and temperatures affect the rates of reactions.