Question

1)
Molecules of gas are tiny, rigid and perfectly
elastic spheres.
​

Answer 1

According to kinetic molecular theory of gases they are perfectly elastic

Answer 2

Molecules of gas are tiny, rigid and perfectly elastic sphere in diameter because of the KINETIC THEORY OF GAS.

EXPLANATION -

° HERE ARE SOME ASSUMPTION ABOUT THE KINETIC THEORY OF GAS -

The kinetic theory of gases is developed with certain assumptions about the nature and state of motion of the molecules of gases. These assumptions are as follows:

• A gas consists of a very large number of extremely small molecules.
• The molecules are rigid and perfectly elastic spheres of very small diameters.
• All the molecules of a given gas are identical.
• Actual volume occupied by the molecules of a gas is very small compared to the volume occupied by the gas. There are lots of empty spaces.
• The intermolecular forces of attraction between gas molecules are negligible.
• The molecules are constantly moving in all possible directions, with different velocities in a random manner.
• In the course of their random motion, the molecules continuously collide with the walls of the container and with each other. These collisions give rise to the pressure exerted by the gas.
• The collisions are perfectly elastic. Hence, there is no loss of kinetic energy during the collisions.
• At a constant temperature, the average kinetic energy of the gas molecules remains constant. The average kinetic energy is directly proportional to the absolute temperature of the gas.

HOPE IT HELPS YOU....