what is the freezing depression 171 g of sucrose in 1.00 kg of water

Answer 1

Colligative properties

∆T - imK

∆T = change in freezing point temperature = ?

i = van't Hoff factor = 1 for sucrose (a non electrolyte)

m = molal concentration = mols sucrose / kg water (see below)

K = freezing point constant for water = 1.86º/m

Finding m:

molar mass sucrose = 342 g/mol

mols sucrose = 171 g x 1 mol / 342 g = 0.50 mols

molality = 0.50 mols / 1.00 kg = 0.500 m

∆T - imK

∆T = (1)(0.500)(1.86)

∆T = 0.93º

(Freezing point of the solution = 0º - 0.93º = -0.93ºC)