Two equal volumes designated 1 and 2, each of which contains a quantity of a classical monatomic gas at the same temperature, are connected by a valve that is closed. If the pressures are initially unequal with P1=2P2, establish a relationship between the chemical potentials µ1 and µ2.
Give a qualitative description of the approach to equilibrium, in terms of changes in pressure and chemical potential, when the valve is opened.