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Homework Help: Specific Latent Heat of Fusion problem

  1. Nov 19, 2008 #1
    1. The problem statement, all variables and given/known data

    An ice tray containing 200 g of water at 25 degrees celecius is placed in the freezer. How much heat energy has to be removed to change the water into ice at -4 degrees celcius?

    2. Relevant equations

    Q= mc(Tf-Ti) + MLf + mc(Tf-Ti)

    3. The attempt at a solution
    I know that the water is changing into ice however im stumped because I don't know if the water is turning to -4 degrees celcius or 0 degrees celcius?

    Any help will be muchly appreciated
    Thankyou
     
  2. jcsd
  3. Nov 19, 2008 #2
    Break it into 3 stages.

    The water drops to freezing point. Then it freezes into ice. Then it drops to -4 degrees.
     
  4. Nov 20, 2008 #3
    i get it now!! Thankyou soo much!
    Kind regards:)
     
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