The kinetic theory predicts a relationship between pressure of a gas and its temperature. Consider an inexpensive container filled with a gas. If the container is heated, the gas molecules will speed up and strike the walls of the container more frequently and with more force. Such action will increase the pressure. This implies that the pressure of a gas increases as its temperature increases and decreases as its temperature decreases. Thus the pressure exerted by a gas is directly proportional to its absolute or Kelvin temperature provided the volume is kept constant.
Basic Assumptions of the Kinetic Theory
i. Gases consist of extremely small particles called molecules. These molecules are so small that their volume is negligible in comparison with the volume of the containing vessel.
ii. The molecules of a gas are in rapid, random straight line motion. They collide with each other and with the walls of the container.
iii. All collisions are perfectly elastic that is, there are no energy losses due to friction.
iv. There are no attractive forces between the molecules.
v. At constant temperature, the average velocity of the molecules of all gases is a constant. If the temperature increases, the average velocity increases.
Kinetic theory of matter states that all matter is made up of very tiny particles which are in constant random motion.