
State the basic assumption of the kinetic theory of gases that leads to the conclusion that there is zero potential energy between the molecules of an ideal gas.
The pressure
and volume
of an ideal gas are related by

where
is the number of molecules,
is the mass of a molecule and
is the mean square speed of the molecules. Use this equation to show that the mean kinetic energy
of a molecule is given by

where
is the Boltzmann constant and
is the thermodynamic temperature.
A cylinder contains
of oxygen gas at a temperature of
. The mass of
of oxygen gas is
. It may be assumed that the oxygen behaves as an ideal gas. Calculate, for the oxygen gas in the cylinder,
the mean kinetic energy of a molecule,
the number of molecules.