Kinetic theory of gases
The founder of modern kinetic theory of heat by common consent
is Daniel Bernoulli. But the credit for having established it on a firm
mathematical basis is due to Clausius and Maxwell in whose hands it attained
the present form.
Postulates of Kinetic theory of gases
A gas consists of a very large
number of molecules. Each one is a perfectly identical elastic sphere.
The molecules of a gas are in a state of continuous and random
motion. They move in all directions with all possible velocities.
(3) The size of each molecule is very
small as compared to the distance between them. Hence, the volume occupied by
the molecule is negligible in comparison to the volume of the gas.
There is no force of attraction or repulsion between the
molecules and the walls of the container.
(5)The collisions of the molecules among themselves and
with the walls of the container are perfectly elastic. Therefore, momentum and
kinetic energy of the molecules are conserved during collisions.
(6)A molecule moves along a straight line between two
successive collisions and the average distance travelled between two successive
collisions is called the mean free path of the molecules.
The collisions are almost instantaneous (i.e) the time of
collision of two molecules is negligible as compared to the time interval
between two successive collisions.
Avogadro number is defined as the number of molecules
present in one mole of a substance. It is constant for all the substances. Its value is 6.023 ? 1023.