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Homework Help: What is the mass of the cup?

  1. Nov 19, 2007 #1
    1. The problem statement, all variables and given/known data

    A 105.05 g ice cube at -15°C is placed in an aluminum cup whose initial temperature is 73°C. The system comes to an equilibrium temperature of 24°C. What is the mass of the cup?

    2. Relevant equations
    Q=mc (delta T)


    3. The attempt at a solution

    the sum of total heat in the system is equal to zero.
    Qice+Qaluminium cup=0
    MiceCice(delta T)+MaluminiumCaluminium(delta T)=0
    I solved for mass of aluminium cup, and got 0.1951 kg. But, it is wrong.
    Please help.
     
  2. jcsd
  3. Nov 19, 2007 #2

    hage567

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    Homework Helper

    Since the ice melts, I think you need to take into account the heat of fusion, Q=mL, where m is the mass of the ice and L is the latent heat of fusion.

    Try that.
     
  4. Nov 19, 2007 #3
    I did, and got 0.8633 kg. But, that is wrong too.
     
  5. Nov 19, 2007 #4

    hage567

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    Homework Helper

    You need to include terms for:
    the heat required to bring the ice from -15 degrees to 0 degrees
    the heat of fusion to melt the ice at 0 degrees to water at 0 degrees
    the heat required to bring the water at 0 degrees to water at the final temperature of 24 degrees

    This will be equal to the heat the aluminum cup loses.
     
  6. Nov 19, 2007 #5
    Thank you very much.
     
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