The purpose of kinetic theory is to deduce the macroscopic properties of an ideal gas from
the motions of its constituent molecules. The fundamental assumptions of kinetic theory are that
a gas held in a container consists of a very large number of molecules that are in ceaseless motion.
Moreover, these molecules are constantly
colliding with one another, and also with the walls of container. Furthermore, the pressure acting on the walls of the
container is the resultant of all of the reaction forces as the molecules strike and rebound from the
walls.
We can make a number of simplifying assumptions in our exploration of kinetic theory. First, the volume of the molecules is assumed to
be negligible. Second, the molecules are assumed not to exert forces on one another, except when they
collide. Third, the collisions of the molecules with the walls are assumed to be specular. The first two
assumptions merely ensure that we are dealing with an ideal gas.
