One mole of an ideal monatomic gas is initially at 300 K and 1.0 atm in a cylinder fitted with a frictionless, massless piston. The cylinder is placed in thermal contact with a large reservoir that is also at 300 K. The gas undergoes a very slow (quasi-static) expansion at constant temperature until its volume doubles.
Assume ideal-gas behavior throughout.
(1) Calculate the change in entropy of the gas during the expansion.
(2) Determine the change in entropy of the thermal reservoir during the expansion.
(3) Find the total change in entropy of the universe for this process and state whether the process is reversible or irreversible on this basis.