What do you mean by kinetic molecular theory of gases? What is its purpose?

This model is used to describe the behaviour of gases. The model itself along with the assumptions regarding elastic collisions, momentum, kinetic energy, random motion, temperature, volume and pressure of gases is known as the kinetic molecular theory of gases. The main postulates of kinetic theory of gases are rapidly moving molecules. The molecules collide with one another and with the walls of the containing vessel.
Purpose: The main purpose of the kinetic theory of gases is to develop a physical picture of the nature of the gaseous state capable of explaining various laws of gaseous behaviour. This theory is applicable only to a perfect or an ideal gas.