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Homework Help: Aluminum Cube Raised Temperature

  1. Nov 28, 2011 #1
    1. The problem statement, all variables and given/known data

    A cube of aluminum is 20 cm on edge. Aluminum has a density 2.7 times that of water (1 g/cm3) and a specific heat 0.217 times that of water (1 cal/g·C). The heat in calories needed to raise the temperature of the cube from 20°C to 30°C is about:

    2. Relevant equations



    3. The attempt at a solution

    I say 470000, book says 47000. Who's right?

    Mass = 20^3 (2.7) = 21600 g

    If 2.17 cal are required to raise 1 gram 1 degree, then 46872 are required to raise 21600 grams 1 degree.

    But we want to raise it 10 degrees, not 1 degree.

    So, 46872 x 10 is about 470000.
     
  2. jcsd
  3. Nov 28, 2011 #2

    gneill

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    Staff: Mentor

    The specific heat of aluminum was stated to be 0.217 times that of water, not 2.17 times.
     
  4. Nov 28, 2011 #3
    Dang! I should have caught that, it's a biological requirement of water to have a pretty high specific heat!!
     
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