ABSTRACT
This chapter concludes with a proof of the equipartition theorem and a brief discussion of the Maxwell velocity distribution for a classical gas. The entropy expression does not allow for possible spin states of the ideal gas particles. The single-particle partition function is given by where the summations are over all translational, rotational, vibrational, and electronic energy states. In dealing with an ideal gas in the classical limit, it is appropriate to attempt a description of the system using classical mechanics rather than quantum mechanics. The discussion given for a classical gas of particles may readily be extended to include particles, such as polyatomic molecules, with internal degrees of freedom. Elegant experiments using molecular beams have verified the Maxwell velocity distribution. For nonideal gases, allowance is made for both potential energy and kinetic energy contributions.
