The kinetic molecular theory of gases provides a model from which we predict the behavior of a gas under certain conditions. The model makes several assumptions and therefore it is said to be valid for an ideal gas. The gas particles move randomly in all directions and in straight lines until they collide with other particles. The volume of the particles is infinitesimal compared to that of the container. There are no intermolecular forces, other than when particles collide.
All collisions are elastic.
The average kinetic energy of an ideal gas is proportional to the Kelvin temperature scale, all gases have the same average kinetic energy at a specific temperature. The cubic container has each side of length l, giving it a volume of l 3 .