Chemistry

Two moles of a nonelectrolyte solute are dissolved in 1 kg of an unknown solvent. The solution freezes at 7.8 degrees Celsius below its normal freezing point. What is the molal freezing point constant of the unknown solvent? What is your prediction for the identity of the solvent?

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  1. m = moles/kg solvent
    m = 2/1 = 2m

    delta T = Kf*m
    7.8 = Kf*2
    Kf = 7.8/2 = ??
    Here is a list of constants. Pick yours.
    http://en.wikipedia.org/wiki/Freezing-point_depression

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  2. -3.9

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  3. Hey, you devide it by 4 not 2, because the number of moles are 2 plus the molality is also 2. and daltatf= kf x m x n for ionic compounds. Answer = 1.95 C

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