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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?

  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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