How does kinetic theory explain the behavior of gases?

The kinetic theory of gases explains the behavior of a gas by modeling it as a collection of numerous identical molecules in constant, random motion. This framework relies on several key assumptions: molecules are separated by distances much larger than their size, they do not interact except through perfectly elastic collisions, and they transfer kinetic energy as heat.1

Under this model, pressure is understood as the result of these random molecular collisions against the walls of a container. Because the average energy of these molecules is dependent on the gas temperature, the theory allows for a direct mathematical relationship between pressure, temperature, and density.1

While this "perfect gas" model effectively approximates behavior in dilute, high-temperature conditions, it requires modifications to account for molecular interactions at high densities or phase changes like condensation. By applying these principles, scientists can derive various macroscopic properties, including viscosity, diffusion, and heat capacity.1