consider a well insulated container of total volume V.
a) Initially the container is divided into 2 equal parts, using a very thin partition. one side is filled with a mole of argon at temperature T and pressure P whereas the other side is under vacuum. at t=0, the partition is suddenly removed. after the system reaches equilibrium, calculate the final temperature and pressure. calculate the change in entropy of the system and of the universe. how would your answer change if the system were in thermal contact with a bath at temperature T.
b) Suppose the partition is replaced with an adiabatic piston. if the gas is allowed to expand reversibly for initial volume V/2 until it occupies the final volume V, calculate the final temperature, pressure and the work done on the piston by the gas. calculate the change in entropy of the system and of the universe. how would your answer change if the system were in thermal contact with a bath at temperature T?