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Which would melt first?

  1. Jul 10, 2015 #1
    So melting point of silver followed by coefficient c/g °c;
    961.8
    .056
    Now golds;
    1064
    .031
    Does that mean the silver melts first?
     
  2. jcsd
  3. Jul 10, 2015 #2
    It depends on your meaning of "first."

    If you are raising T slowly so that both materials stay in near equilibrium with their surroundings, silver will melt first.

    If one is adding heat at a constant rate, then one needs the heat of fusion and the initial temperature and masses to determine which would melt first.
     
  4. Jul 10, 2015 #3
    No, it doesn't. It may, but it depends on other parameters. The size of the two samples, the rates of heat transfer into and out of the two samples.
    And also, on what do you mean by "melts first". It is completely liquid or just "starting to melt".
     
  5. Jul 10, 2015 #4

    CWatters

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    The figures with units c/g °c are for the specific heat capacity.

    If you started with 1gram of both at room temperature (20c) and heated both samples it you would find it would take a different amount of energy for each one to reach melting point. For example it would take..

    For silver... E = 1 * (961-20) * 0.056 = 53 calories
    For gold.... E = 1 * (1064-20) * 0.031 = 32 calories

    So although silver has a lower melting point it takes more heat to get there.

    So the answer depends on how the samples are heated as Dr Courtney said. If they are put in an oven together and the temperature increased slowly then Silver melts first. If you heat each one separately using something like a constant power electrical heater then gold melts first because it takes less energy.
     
  6. Jul 10, 2015 #5
    Thanks exactly what i was asking couldnt word it for the life of me though haha much appreciated
     
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