17. (a) The final mass of ice is (1773 g + 227 g)/2 = 1000 g. This means 773 g of water froze. Energy in the form of heat left the system in the amount mLF, where mis the mass of the water that froze and LFis the heat of fusion of water. The process is isothermal, so the change in entropy isΔS = Q/T = –mLF/T= –(0.773 kg)(333 ×103J/kg)/(273 K) = −943 J/K. (b) Now, 773 g of ice is melted. The change in entropy is === +943 J/K.FQmLSTTΔ(c) Yes, they are consistent with the second law of thermodynamics. Over the entire cycle, the change in entropy of the water-ice system is zero even though part of the cycle is irreversible. However, the system is not closed. To consider a closed system, we must
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This note was uploaded on 06/03/2011 for the course PHY 2049 taught by Professor Any during the Spring '08 term at University of Florida.