Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

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

    User Avatar
    Homework Helper

    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

    User Avatar
    Homework Helper

    You're welcome! :)
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook