Consider a reversible isothermal expansion of an ideal gas in contact with the reservoir at temperature T , from an initial volume V1 to a final volume V2 . (a) What is the change in the internal energy of the system? (b) Calculate the work done by the system. (c) What is the amount of heat absorbed by the system? (d) Find the change of entropy of the system. (e) Find the change of the entropy of the system plus the reservoir.