If the freezing point of pure toluene is -95.15 oC and its freezing point depression constant is -8.38 oC/molal, what is the freezing point of a solution made by dissolving 39.338g of anthracene (C14H10) in 150.0mL of toluene? (Density of toluene = 0.8669g/mL)

Question

If the freezing point of pure toluene is -95.15 oC and its freezing point depression constant is -8.38 oC/molal, what is the freezing point of a solution made by dissolving 39.338g of anthracene (C14H10) in 150.0mL of toluene?    (Density of toluene = 0.8669g/mL)

DrBob222 · Answer

mol anthracene = grams/molar mass grams toluene = volume x density molality = mol anthracene/kg toluene. delta T = Kf*m. Solve for delta T. Subtract from zero to find new freezing point.