Gas molecules are said to be perfectly elastic because
Answer Details
Gas molecules are said to be perfectly elastic because they collide without loss of energy. When gas molecules collide with each other, they exchange energy and momentum, but the total energy and momentum of the molecules remain constant. This is due to the fact that gas molecules are very small and have negligible attractive forces between them. As a result, they are able to move about freely in straight lines and collide with each other in a perfectly elastic manner, without any loss of energy. Therefore, when gas molecules collide, they bounce off each other with the same energy that they had before the collision. This property of gas molecules is known as perfect elasticity, which is a key characteristic of gases.