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Large error for my freezing point depression.

  1. Nov 4, 2008 #1

    1. The problem statement, all variables and given/known data
    Find theoretical freezing point of depression.
    It's 30.07g NaCl(s) dissolved into 100.08 g of water/ice
    Kf= -1.86 etc..

    2. Relevant equations
    Freezing Point Depression = Kf * i * m

    3. The attempt at a solution

    I have van't hoff factor (i) = 2
    but i calculuated 1.0943 mol NaCl / .10008 kg water = molality = 10.934 molal/kg
    I end up getting -40 C for the answer?

    When I do the same operation for sucrose, calcium chloride (dihydrate) and aluminum chloride (hexahydrate) i get numbers in the hundreds, what am i doing wrong.
    Last edited: Nov 4, 2008
  2. jcsd
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