Question

A solution is prepared by dissolving 0.490 g of an unknown compound in 50.00 mL of water. The freezing point of the solution is –0.201°C. Assuming the compound is a non-electrolyte, what is the molecular mass of the compound? Use 1.00 g/mL as the density of water.
delta T = 0-(-.201) = ?
delta T = Kf*m
You know delta T and Kf, solve for m = molality.
m = mols/kg solvent. You know kg solvent and m, solve for mols.

mols = grams/molar mass. You know grams and mols, solve for molar mass.
90.74

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