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Homework Help: Heat and Temperature Change

  1. Feb 7, 2010 #1
    1. The problem statement, all variables and given/known data
    A thermos contains 150 cm3 of coffee at 85 oC. To cool the coffee, you drop two 11g ice cubes into the thermos. The ice cubesare initially at 0 oC
    and melt completely. What is the final temperature of the coffee? (Treat the coffee as if it were water)



    2. Relevant equations
    Qf = mLfusion
    Q = mcΔT

    3. The attempt at a solution

    I am trying to help someone with this problem. They have yet to learn about internal energy, so I am a little lost (forgetful) as to how to approach this problem
    and explain it so that it makes sense.



    How would you approach this problem?

    Thanks,
    Casey
     
  2. jcsd
  3. Feb 7, 2010 #2
    I know that the final temps of coffee and ice will be the same since they reach equilibrium. I also know that there should (probably) be 3 terms: Q of the coffee, Q of the ice melting, and Q of the melt-water changing temp.

    But I cannot figure out out to set up a balanced equation...
     
  4. Feb 7, 2010 #3
    I got it...Total heat transfer with environment = 0.....piece of cake...
     
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