Question

An aqueous solution containing 35.1 grams of an unknown molecular (noneolectrolyte) compound in 152.5 grams of water was found to have a freezing point of -1.8 degrees C. Calculate the molar mass of the unknown compound.

Answer 1

delta T = Kf*molality
Solve for molality

molality = moles/kg solvent
Solve for moles

moles = grams/molar mass
solve for molar mass.