A solution is prepared by dissolving 4.9g of sucrose in 17g water. Calculate the boiling point, freezing point and osmotic pressure of this solution at 25 degree Celsius.

Answer 1

mols sucrose = grams/molar mass = 4.9/342 = ?
m = molality = mols sucrose/kg solvent = ?mols sucrose/0.017 kg = ?
dT = Kf*m. You have Kf for water and molality from above. Solve for delta T then normal freezing point - delta T = new freezing point. Kf is 1.86 for water.

dT = Kb*m
You have Kb for water (0.512), m from above, solve for delta T. Then normal boiling point for H2O + delta T = new boiling point.

osmotic pressure = MRT
You know T (remember to use kelvin), and R (universal gas constant). Convert molality (m) to molarity (M) and solve for osmotic pressure. For very dilute solutions m may be used interchangeably with M
Post your work if you get stuck.