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Homework Help: Find the total entropy of the system?

  1. Dec 6, 2011 #1
    1. The problem statement, all variables and given/known data
    If 2.00 m3 of water at 0°C is frozen and cooled to -25°C by being in contact with a great deal of ice at -25°C, what would be the total change in entropy of the process?


    2. Relevant equations
    ΔS=Q/T Q=mL Q=mcΔT


    3. The attempt at a solution
    2000 * 4190 * ln (273/(273-25) + 2000* 336000/273 = 265854.8 J/K
    Why is natural log being used?
     
  2. jcsd
  3. Dec 6, 2011 #2

    I like Serena

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    Hi gibson101! :smile:

    The natural log is used because ΔS depends on the temperature, which is changing during cooling.
    This means that ΔS needs to be integrated ([itex]\Delta S=\int {dQ \over T}[/itex]) yielding the natural log.
     
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