determine the expected freezing point of a cacl2 solution prepared at room temperature from 2.55 kg of calcium chloride and 33.8 Liters

Answer 1

Delta T = imK

Delta T = change in freezing point

i = van’t Hoff factor = 3 forcCaCl₂

m = molality = moles solute/kg solvent = see below

K = freezing point constant for water = 1.86

molality = m = moles/kg

moles = 2.55 kg x 1000 g/kg x 1 mole/111 g = 22.97 moles

kg solvent = 33.8 liters x 1 kg/liter = 33.8 kg

m = 22.97 mol/33.8 kg = 0.6796 molal

Delta T = (3)(0.6796)(1.86) = 3.79 degrees

Expected freezing pointv= -3.8 degrees C