Question

What is the freezing point of a solution made by dissolving 450 g of ethylene glycol (C2H6O2) in 550 g of water? The freezing point of pure water is 0.0ºC and Kf of pure water is -1.86ºC/m.

Answer 1

moles ethylene glycol = grams/molar mass.
Solve for moles.

m = moles solute/kg solvent
Solve for m

delta T = Kf*m
solve for delta T, then for T.

Answer 2

-8.32