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The release of HEAT

  1. Jul 23, 2003 #1
    Can anyone help me with the following question.

    How much heat is released when a lake of surface area 8.5 km^2 freezes to a depth of 1.0m? assume the water is initially at 0 degree C. The answer is 6.2 X10^11 Kcal.


    any help is approciated.
  2. jcsd
  3. Jul 23, 2003 #2
    Look up Newton's law of cooling, it should help you to figure that one out.
  4. Jul 23, 2003 #3


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    It is really much simpler then Newtons law of cooling. Since the water is at 0C already there is no temperature change involved. You know the volumn of Ice forming (area x thickness) and you should know about the heat of fusion of Ice, this is given as some number of Kcals per mole of water, simple multiplication.

    If I told you any more I would be doing the problem for you.
  5. Jul 23, 2003 #4
    Since i'm a chemist, i would find out the number of mol's of water you have frozen and then use the kj/mol of fusion. Thus giving it to you. but you physics people might have an easier way :-)

  6. Jul 23, 2003 #5
    got it.
    thanks everyone.

    is just that the supplied answer is somehow wrong which confuse me.
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