​Kinetic-molecular theory:

1. Gases consist of large numbers of molecules that are in continuous, random motion

2. The volume of all the molecules of the gas is negligible compared to the total volume in which the gas is contained

3. Attractive and repulsive forces between gas molecules are negligible

4. Energy can be transferred between molecules during collisions, but the average kinetic energy of the molecules does not change with time, as long as the temperature of the gas remains constant

5. The average kinetic energy of the molecules is proportional to absolute temperature. At any given temperature, the molecules of all gases have the same average kinetic energy