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Math Help - Not sure which formula to start out with.

  1. #1
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    Not sure which formula to start out with.

    An experiment involved in pouring 150g of heated copper into a 375 g aluminum cup containing 200g of water at 25 deg C. The mixture reached 28 deg C. What was the initial temp of the copper?



    Is this Thermal equiliabrium?? mc delta T = mc delta T, but I have 3 items.
    How do I compare 3 things?? Or do I do water to the cup and the copper to the cup??

    Help if you can, thanks.
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  2. #2
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    Looks to me like it's this simple:
    Code:
    200 @ 25
    150 @ x
    ========
    350 @ 28
    So (200(25) + 150x) / 350 = 28
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  3. #3
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    The answer is 89.41 deg celcius. Not sure what you did there. unless you care to explain. I can't get 89.41. I am way off on the number.
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  4. #4
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    All I did was a simple "proportion", like:
    buy 200 apples for 25 cents each, plus 150 bananas, for average price of 28 cents per fruit:
    what's the price per banana?
    But evidently not what you're after...
    Perhaps a chemistry/physics expert will step in and help you...
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