Question

State the main postulates of kinetic theory of matter.

Answer 1

All matter is made up of molecules. The molecules of a gas are in state of rapid and continuous motion. Their velocity depends upon temperature. Using this molecular motion, various properties of gases for example temperature, energy and pressure, etc. can be explained very easily.

Complete step by step answer: The main postulates of kinetic theory of matter is given as follows:
(1) All the gases consist of molecules. The molecules are rigid, elastic spheres identical in all respects for a given gas and different for different gases.
(2) The size of a molecule is negligible compared to the average distance between the molecules.
(3) The molecules are in a state of continuous motion which moves in all directions with all possible velocities.
(4) During the random motion, the molecules collide with one another and with the walls of the vessel.
(5) The collisions are perfectly elastic in nature and there are no forces of attraction or repulsion between the molecules. Thus, all internal energy of the gas is nothing but kinetic energy.
(6) Between two collisions, a molecule moves in a straight path such that molecules have uniform velocity.
(7) In spite of the molecular collisions, the density remains uniformly throughout the gas.

Note: According to kinetic theory, the molecules of a gas are in a state of continuous motion. The molecules collide with one another and also with the walls of the container. Whenever a molecule collides with the walls of the container, it returns with a changed momentum and an equal momentum is transferred to the wall.