In a sample of oxygen gas at room temperature, the average kinetic energy of all the balls stays constant. Which postulate of kinetic molecular theory best explains how this is possible?

A. Attractive forces between gas particles are negligible because the particles of an ideal gas are moving so quickly.

B. Collisions between gas particles are elastic; there is no net gain or loss of kinetic energy.

C. Gases consist of a large number of small particles, with a lot of space between the particles.

D. Gas particles are in constant, random motion, and higher kinetic energy means faster movement.

It would be B.

Explanation:

Collisions between gas particles are elastic.

An elastic collision means there is no net gain or loss of kinetic energy due to the collision. This means a sample of gas will have a constant average kinetic energy at a constant temperature and volume.

The answer is: B. Collisions between gas particles are elastic; there is no net gain or loss of kinetic energy.

The Kinetic Molecular Theory of Matter

1) Matter is composed of tiny particles (in this example oxygen molecules).

2) These particles are in constant, random motion and possess kinetic energy.

3) The particles also have potential energy due to intermolecular attractions.

4) The average kinetic energy increases as the temperature increases.

5) Energy is transferred from one particle to another during collisions, but at constant temperature the total energy of the system is constant.

Kinetic energy is energy associated with motion.