The basic tenets of Kinetic Molecular Theory (KMT) as they relate to gases:

Particles of a gas:

a.       are in constant motion, moving in straight lines until they collide with another particle or a wall of the container in which they are enclosed.

b.      experience elastic collisions; i.e., they do not eventually “run down”.

c.       do not stick to other particles.

The speed of the particles is related to their temperature.

The pressure of a gas is related to the frequency and impact of the collisions of the gas particles with the sides of the container in which they are enclosed.