A rigid, nonconducting tank with a volume of 4 m^3 is divided into two unequal parts by a thin membrane. One side of the membrane, representing 1/3 of the tank, contains nitrogen gas at 6 bar and 100 degree C, and the other side, representing 2/3 of the tank, is evacuated. The membrane ruptures and the gas fills the tank. Describe a reversible process by which the gas can be returned to its initial state. How much work is done? Assume nitrogen is an ideal gas for which Cp = (7/2)R and Cv = (5/2)R.