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Homework Help: Need help with latent heat involving ice and steam

  1. Dec 10, 2009 #1
    1. The problem statement, all variables and given/known data

    A well-insulated bucket of negligible heat capacity contains 177 g of ice at 0°C.

    (a) If 20 g of steam at 100°C is injected into the bucket, what is the final equilibrium temperature of the system? I've already solved this part to be 0 degrees Celsius.

    (b) What mass of ice remains?

    2. Relevant equations

    Q = mc(deltaT)

    m = Q/Lf

    3. The attempt at a solution

    From the example in the textbook, it seems I only have to find the heat necessary to cool the steam from 100 degrees to 0 degrees, and then divide this number by the latent heat of ice (333.5 kJ/kg). 2.02 is the specific heat of steam. So, I did (.02)(2.02)(100). This gave me a heat of 4.04 kJ. I then divided this number by the latent heat of ice, 333.5, and came out with an answer of .01211 kg. I converted this to g (12.11 g), and subtract this from 177. My final answer was 164.886457 g, but this is incorrect. Help?
  2. jcsd
  3. Dec 10, 2009 #2
    Does nobody know?
  4. Dec 10, 2009 #3
    Phase change for water is different going from steam to liquid and then to water:

    Total energy change= that going from steam to water-that going to from 100 to zero degrees-and then that from going liquid to freezing.

    There are three seperate constants at work.
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