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Homework Help: How much ice must melt at 0 deg. C to gain 5 g of mass?

  1. Feb 13, 2007 #1
    1. The problem statement, all variables and given/known data
    How much ice must melt at 0 deg. C to gain 5 g of mass?

    Latent Heat of Fusion = limg145.gif

    2. Relevant equations
    I cannot seem to find many equations that relate thermodynamics and mass, maybe that is my biggest problem... The only one i could find was

    3. The attempt at a solution
    I know the latent heat of fusion, but i do not know Q. I tried dividing both sides by L, giving me Q/L=m, but i wasn't sure where to go from there.

    Attached Files:

  2. jcsd
  3. Feb 13, 2007 #2
    This question is incomplete or bizarre. Heating or cooling will certainly affect density but not mass. In other words, you know that ice floats. On melting, it becomes more dense as it now occupies less volume ( a very useful property of H2O BTW). Now in the bizarro realm you could I suppose use Einstein's mass-energy equivalency E=Mc^2 by computing the energy required to double the apparent mass. But that is way, way out there. Check the ? and repost.
  4. Feb 14, 2007 #3
    wow i have the same exact problem for my physics class and i can not figure it out either.
  5. Feb 14, 2007 #4
    Someone suggested something to me and i tried it and it worked. E=mc^2
    E=.005 kg* (3.0x10^8)^2. Thats the energy (in Joules) needed so take that convert it to cal and divide by the Latent Heat Fusion. Thatwill give you the # of grams. Hope this helps.
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