What is the freezing point of a solution of ethylene glycol (antifreeze), a nonelectrolyte, that contains 290. g of C2H6O2 dissolved in 120. g of water?

Question

freezing point	0.00°C
boiling point	100.00°C
Kf	1.86°C/m
Kb	0.512°C/m

Use molar masses with at least as many significant figures as the data given

Answer 1

Colligative properties:

Freezing point depression ... ∆T = imK

∆T = change in freezing point temp = ?

i = van't Hoff factor = 1 for ethylene glycol since it's a non electrolyte

m = molality = moles EG/kg water = 290. g EG x 1 mol EG/62.07 g = 4.672 mol / 0.120 kg = 38.93 m

K = freezing constant = 1.86º/m

Solving for ∆T we have...

∆T = (1)(38.93)(1.86) = 72.4º

New freezing point of the solution would be 0 - 72.4º = -72.4ºC