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Rearranging equation for heat capacity

  1. Oct 27, 2012 #1
    1. To determine whether a shiny gold rock is actually gold, a student decides to measure its heat capacity. She first weighs the rock and finds it has a mass of 4.7g. She then finds that upon absorbtion of 57.2 J of heat, the temperature of the rock rises from 25 degree Celsius to 57 degree Celsius. Find the specific heat capacity of the substance composing the rock and determine whether the value is consistent with the rock being pure gold.

    2. q = m X Cs X temperature change
    Cs of gold = 0.128 J/g x Celsius

    3. 4.7g X 0.128 J/g x C X 32 C = 19.25
    c = 9/temperature change = J/C = 57.2/32 C
    4.7g X 32 C / 57.2 J

    Actual solution: 57.2 J / 4.7g X 32 C

    So my question is; why is 57.2 divided by the others, when if you had brought it over from the other side, wouldn't you divide it BY 57.2?
  2. jcsd
  3. Oct 27, 2012 #2


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    Staff: Mentor

    No idea what you are doing here.

    [tex]q = mc_s\Delta T[/tex]

    Solve for cs. Don't put numbers into the equation yet, just solve symbolically.
  4. Oct 27, 2012 #3
    How do you do that... why are chemists so cryptic
  5. Oct 28, 2012 #4


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    Staff: Mentor

    Solve symbolically means rearrange so that cs will be on the left hand side of the equation and everything else will be on the right hand side.

    There is nothing cryptic here, this is basic algebra that you should learn long ago. And if you have read forum rules you know we don't give final answers, we rather help you solve the problem guiding you in the right direction.
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