Two identical copper blocks, Block H and Block C, each of mass 0.80 kg, are placed in thermal contact inside a perfectly insulated container. Initially Block H is at a uniform temperature of 400 K and Block C is at 300 K. After a long time the two blocks reach a common final temperature of 350 K. Assume the specific heat capacity of copper is constant over the temperature range considered and that no energy leaves the two-block system.
Answer the following questions. (Treat the two blocks together as an isolated system.)
(a) Describe the direction of energy transfer between the two blocks during the approach to equilibrium and identify which block gains thermal energy.
(b) State whether the entropy change ΔSH of Block H is positive, negative, or zero, and briefly justify your answer.
(c) State whether the entropy change ΔSC of Block C is positive, negative, or zero, and briefly justify your answer.
(d) Using your answers to parts (b) and (c), discuss the sign of the net entropy change ΔSsystem for the two-block system and explain how this result is consistent with the second law of thermodynamics.