Thursday, August 18, 2011

Assumptions in the Kinetic Theory of Gases

The kinetic theory of gases is based on the following assumptions:
1. The volume of a gas consists of a large number of minutes particles called molecules. it has been experimentally found that there are about 26.8*10(power 18) molecules in 1ml of a gas at N.T.P.
2. The molecules are mere mass points. In other words, the size of a molecules is assumed to be negligible, as compared to the distance between the molecules.
3. The gas molecules are perfectly elastic sphere and exert negligible force of attraction or repulsion on one another, or on the walls of the containing vessel. Hence in a direct impact, the molecules rebound with the same velocity after each collision.
4. The molecules are continuously colliding against each other, and with the walls of the containing vessel.Between two collisions, a molecule moves in a straight line. This distance is called the free path of the molecule.
5. The time during which a collision takes place is negligible as compared to the time required to transverse the free path, i.e collisions are instantaneous.