A 65-g ice cube is initially at 0.0C. (a) Find the change in entropy of the cube after it melts completely at 0.0C. (b) What is the change in entropy of the environment in this process? Hint: The latent heat of fusion for water is 3.33 105 J/kg.

A sealed container holding 0.500 kg of liquid nitrogen at its boiling point of 77.3 K is placed in a large room at 21.0C. Energy is transferred from the room to the nitrogen as the liquid nitrogen boils into a gas and then warms to the rooms temperature. (a) Assuming the rooms temperature remains essentially unchanged at 21.0C, calculate the energy transferred from the room to the nitrogen. (b) Estimate the change in entropy of the room. Liquid nitrogen has a latent heat of vaporization of 2.01 105 J/kg. The specific heat of N2 gas at constant pressure is CN2 = 1.04 103J/kg K.

(a) How much heat transfer occurs from 20.0 kg of 90.0C water placed in contact with 20.0 kg of 10.0C water, producing a final temperature of 50.0C ? (b) How much work could a Carnot engine do with this heat transfer, assuming it operates between two reservoirs at constant temperatures of 90.0C and 10.0C ? (c) What increase in entropy is produced by mixing 20.0 kg of 90.0C water with 20.0 kg of 10.0C water? (d) Calculate the amount of work made unavailable by this mixing using a low temperature of 10.0C, and compare it with the work done by the Garnet engine. Explicitly show how you follow the steps in the Problem-Solving Strategies for Entropy. (e) Discuss how everyday processes make increasingly more energy unavailable to do work, as implied by this problem.