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Homework Help: Amount of energy needed to melt a solid

  1. May 11, 2015 #1
    1. The problem statement, all variables and given/known data
    A jeweler heats 25g of pure gold until molten. If the initial temperature of the gold is 22 degrees celcius, calculate the amount of energy required for the process.

    2. Relevant equations
    c = 129
    Lf= 64 500
    Lv = 1578000
    Tmelt = 1064

    3. The attempt at a solution
    Q = mct
    = 0.25kg(129)(1064-22)
    = 33605J
  2. jcsd
  3. May 11, 2015 #2
    You need to add the latent heat of fusion. The problem statement indicates that the gold in the final state is molten.

  4. May 12, 2015 #3


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    And please get in the habit of indicating units for the quantities used in your calculations. It is very confusing otherwise.
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