Consider 1.0kg of pure water at atmospheric pressure and 0∘C. Two different processes are carried out separately on identical samples:
Process I – The water is initially solid (ice). Thermal energy is supplied from a large reservoir at 0∘C until the sample becomes completely liquid.
Process II – The water is initially liquid. Thermal energy is removed and deposited into a large reservoir at 0∘C until the sample becomes completely solid.
Answer the following questions concerning the entropy changes for each process.
(a) For Process I, state whether the entropy change ΔSwater of the sample is positive, negative, or zero, and explain your reasoning in terms of molecular disorder.
(b) For Process II, state whether ΔSwater is positive, negative, or zero, and explain.
(c) Compare the magnitudes of ∣ΔSwater∣ for the two processes and account for any similarities or differences.
(d) For each process, discuss the sign of the entropy change of the reservoir and comment on the total entropy change of the universe.