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Homework Help: What was the initial temperature of the copper?

  1. Apr 25, 2010 #1
    1. The problem statement, all variables and given/known data

    8.0 g of aluminum at 200 C and 22 g of copper are dropped into 55 cm^3 of ethyl alcohol at 15 C. The temperature quickly comes to 28 C. What was the initial temperature of the copper?


    2. Relevant equations



    3. The attempt at a solution

    tried using calorimetry equations, not getting anywhere.
     
    Last edited: Apr 25, 2010
  2. jcsd
  3. Apr 25, 2010 #2
    Have to give the equations i haven done SHC for 3years although i dont think that that question is hard.
     
  4. Apr 26, 2010 #3
    heat lost = heat gained
    or m1 * s1 * t1 + m2 * s2 * t2 + m3 * L = m1 * s1 * tf + m2 * s2 * tf + m3 * s3 * tf
    solving the above equation for t2 we get
    t2 = (m1 * s1/m2 * s2) * (tf - t1) + (m3/m2 * s2) * (s3 * tf - L)
    m1 = 11 g = 11 * 10^-3 kg
    s1 = 900 J/kg/K
    t1 = 200 oC = (200 + 273) K = 473 K
    m2 = 21 g = 21 * 10^-3 kg
    s2 = 387 J/kg/K
    t2 = the initial temperature of copper
    m3 = ρ * V = 790 * 46 * (10^-2)^3 = 36.34 * 10^-3 kg
    L is the latent heat of fusion of ethyl alcohol and is equal to 1.08 * 10^5 J/kg
    tf = 22 oC = (22 + 273) K = 295 K


    not working.
     
    Last edited: Apr 26, 2010
  5. Apr 26, 2010 #4

    ehild

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    Homework Helper

    I do not see any water in the problem.

    ehild
     
  6. Apr 26, 2010 #5
    thanks for the notice, edited it, and stil not getting the correct answer
     
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