Question

a solution containing 100g of unknown liquid and 900g water has a freezing point pf -3.33 C. given kf=1.86 degrees c for water, the moelcular weight of the unknown liquid is what?

Answer 1

delta T = Kf*molality
Solve for m

m = #moles/kg solvent
Substitute m and kg solvent, solve for # moles.

# moles = grams/molar mass
You have #moles and grams, solve for molar mass.