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Homework Help: Finding entropy change when house leaks heat

  1. Dec 18, 2011 #1
    1. The problem statement, all variables and given/known data
    b) The temperature inside a house is Tin = 19.2° C when the temperature outside is Tout = 10.7° C. If Q = 5.49 kJ of heat leak from the house to the outside, find the change in entropy caused by this process.


    2. Relevant equations
    W = QH - QC, dS = dQ/T


    3. The attempt at a solution
    dS = 5.49kJ/283.7K = .0193514276kJ/K

    The answer I calculated was wrong, should I include the entropy inside the house?
    Any help is appreciated!
     
  2. jcsd
  3. Dec 18, 2011 #2

    I like Serena

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    Hi rubenhero! :smile:

    Inside you lose ΔS=-Q/TH.
    Outside you gain ΔS=Q/TL.

    The question in your problem statement is not entirely clear, but I suspect the total change in entropy is intended, which is the sum of both entropy changes.
     
  4. Dec 18, 2011 #3
    Thanks you for responding. You were right, I just did the sum of the entropy loss and gain and got an answer of .5629265733 J/K. Webassign marked my answer as right. Thanks again for your help!
     
  5. Dec 18, 2011 #4

    I like Serena

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    You're welcome! :)
     
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