Consider an isolated system (no heat, matter or work may be exchanged with the surroundings) consisting of three internal compartments A, B, and C, of equal volumes. The compartments are separated by partitions; each partition has a valve which may be opened remotely. Initially the central volume B is filled with a gas at 298K (25 deg C) and the outer two are evacuated. Consider the following two processes: (a) The valve to the A side is opened, the gas expands freely into compartment A, and the system comes to equilibrium. Then, the valve to the C side is opened and the system again comes to equilibrium.
(b) Both valves are opened simultaneously, the gas expands freely into both compartments and the system comes to its equilibrium.
Which of these processes produces more entropy?