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Homework Statement
Suppose that you want to freeze 0.7 kg of water for a party, and only have 12 minutes to do it. The temperature inside the refrigeration unit is 273 K, and the temperature outside is Thot = 309 K. Since you are a brilliant UW student, assume that your refrigerator has the maximum possible efficiency. Assume also that the initial temperature of the water is 273 K. The Latent Heat of Fusion of water is 3.33×105 J/kg.
What is the change in entropy in the water per second in J/K s?
Homework Equations
change in entropy (S) = energy absorbed or expelled/constant temperature
The Attempt at a Solution
I have found that the Qhot/time =366.44J/sec
Qcold/time =323.75J/sec
By my understanding the delta S should = .7kg * 3.33E5 J/kg / (273K*720sec)
But 1.18 J/K*sec is not an accepted answer.
What am I doing wrong?