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Homework Help: [Thermodynamics] Impossible Heat Transfer Problem

  1. Oct 1, 2012 #1
    An insulated Thermos contains 122 g of water at 91°C. You put in a 13.7 g ice cube at 0°C to form a system of ice + original water.

    Use mc(ΔT) |water + mc(ΔT) |ice + Lm |ice = 0

    Final T = [(m*c*T) |water + (m*c*T) |ice - (L*m) |ice] / [m*c |water + m*c |ice]

    Final T = [(.122*4.18*364) + (.0137*2.108*273) - (334*.0137)] / [.122*4.18 + .0137*2.108]

    [STRIKE]Final T = 77.63K[/STRIKE]

    What am I doing wrong??
  2. jcsd
  3. Oct 1, 2012 #2


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    Gold Member

    assuming you went from
    What is L and why is it 334.
  4. Oct 1, 2012 #3
    In the denominator, you should be using the heat capacity of liquid water in both terms, since the ice is melted.
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