Freezing point depression = Tf = freezing point of water - freezing point of solution = 0.0 - 1.7 = 1.7oC Freezing point depression constant of water Kf = 1.86oC/m Tf = Kf x m Molality m = Tf/Kf = 1.7/1.86 = 0.9140m Mass of water = 150.0 g = 0.150 kg Molality = moles of compound/mass of water in kg = moles of compound/0.150 = 0.9149 Moles of compound = 0.9149 x 0.150 = 0.1371 mol Molar mass of compound = mass/moles of compound = 40.2/0.1370 = 293 g/mol Solution Freezing point depression = Tf = freezing point of water - freezing point of solution = 0.0 - 1.7 = 1.7oC Freezing point depression constant of water Kf = 1.86oC/m Tf = Kf x m Molality m = Tf/Kf = 1.7/1.86 = 0.9140m Mass of water = 150.0 g = 0.150 kg Molality = moles of compound/mass of water in kg = moles of compound/0.150 = 0.9149 Moles of compound = 0.9149 x 0.150 = 0.1371 mol Molar mass of compound = mass/moles of compound = 40.2/0.1370 = 293 g/mol.