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Homework Help: This problem is MESSED up

  1. Sep 28, 2005 #1
    A 150g copper bowl contains 220g of water. Both bowl and water are at 20 degrees C. A very hot 300g copper cylinder is dropped into the water. This causes the water to boil, with 5g being converted to steam, and the final temperature of the entire system is 100 degrees C. a) how much heat is transfered to the water? b) how much to the bowl? c)what is the original temperature of the cylinder?

    I get the jist of this problem but what i dont know is what to sub in for the mass of water, do i use 220g? or 215g since 5 is boiled away? Something else i dont get is when it says the energy transfered to the water, does that mean the energy transfered to the liquid water and the steam? or just the liquid?
  2. jcsd
  3. Sep 28, 2005 #2


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    You have two components - liquid water and gaseous water. The liquid water was merely heated while the gaseous water (steam) underwent a phase change --- which requires additional energy! :)
  4. Sep 28, 2005 #3


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    Heat has to be transferred to the water before it becomes steam! Calculate the heat necessary to raise 220 g of water to from 20 C to 100 C. Then calculate the heat necessary to change 5 g of water into 5 g of heat. That's the "heat transferred to the water".

    Also then calculate the heat necessary to raise 150 g of copper from 20 C to 100 C.

    Finally, if the total amount of heat you just calculated were put back into the 300 g copper cylinder, it would raise the temperature of that cylinder from 100 C to what?
  5. Sep 28, 2005 #4
    ah yes, it is as i suspected.
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