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Homework Help: Heat Removed

  1. May 11, 2010 #1
    1. The problem statement, all variables and given/known data

    How much heat must be removed when 130 g of steam at 145°C is cooled and frozen into 130 g of ice at 0°C. (Take the specific heat of steam to be 2.01 kJ/kg·K.)

    Answer is in kcal.

    2. Relevant equations

    sht.gif

    3. The attempt at a solution

    I know steam turns back into water at 100°C

    Q1=C1m(deltaT)
    Q1=(2010 J//kg·K)(.13kg)(418.15K-373.15K)

    In the second part, instead of using the specific heat of steam, I used the specific heat of water= 4.186 joule/gram °C

    Q2=C2m(deltaT)
    Q2=(4.186 J/g·°C)(130g)(100°C)

    I then added Q1 to Q2 and came up with an answer in Joules.
    1 joule = 0.000239005736 kilocalories

    But my answer is wrong. Anyone see what I missed? Probably a conversion issue.
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. May 11, 2010 #2

    Borek

    User Avatar

    Staff: Mentor

    Condensation (latent heat).
     
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