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Homework Help: Change in Entropy

  1. Feb 7, 2010 #1
    1. The problem statement, all variables and given/known data

    Find the change in entropy when 2.00 kg of water at 100 degrees C is boiled away to steam at 100 degrees C. Give your answer in kJ/K

    2. Relevant equations
    deltaS=Q/T
    Q=m*Lvaporization


    3. The attempt at a solution
    Q=m*Lvaporization
    Q=2 kg * 22.6*10^5 J/kg
    Q = 4.52x10^6 J

    I'm not not sure how to find T though since it's at 100 degrees and going to 100 degrees...

    Thanks!
     
  2. jcsd
  3. Feb 8, 2010 #2
    There's a good deal of views on here, does no one know how to do this? ;)
     
  4. Feb 8, 2010 #3

    Andrew Mason

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    Science Advisor
    Homework Helper

    T is given. All you have to do is put it in the correct scale. The denominator in [itex]\Delta Q/T[/itex] is the absolute temperature at which the heat flows into the water.

    AM
     
  5. Feb 8, 2010 #4
    Oh, I thought I had to do something more complicated with the T. Thanks!
     
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