Question

Ice cubes at 0°C are poured into a glass that initially contains 150 g of liquid water at 20°C. The contents of the glass are gently stirred. After a short time, some of the ice melts, and the liquid cools to 0°C. No appreciable heat exchange occurs between matter inside the glass with matter outside the glass during this process. (a) Calculate the entropy change of the universe during the process. Use only the following data:the constant pressure heat capacity of liquid water is approximately 4.18 J/(g K) over the temper-ature range of interest. You may further presume that the density of water is constant over the temperature range. (b) If the same process were performed reversibly, how much useful work would be obtained from it? Any required heat exchange to achieve the same final state reversibly should be with matter outside the glass, which are at 20°C.

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