One mole of He at 25 °C and 2 bar is expanded reversibly and isothermally to a pressure of 0.142 bar.
A) How much work is done, is the work done on the surroundings or on the system and what is the change in internal energy?
B) How much work is done and what is the change in internal energy if the gas is expanded against a constant pressure of 0.142 bar.
C) If you wanted to capture the maximum amount of energy how would you do the expansion?