The freezing point of a cyclohexane sample is 6.20*C. A soltuion is prepared by dissolving 0.4660g of an unknown solute in 36.0g cyclohexane. The freezing point of the solution if 4.11*C. Calculate the molar mass of the unknown solute. Kf for cyclohexane is 20.0*Ckg/mole.

Answer 1

delta T = Kf*molality
Solve for molality.

molality = moles/kg solvent
Solve for moles.

moles = grams/molar mass
Solve for molar mass.