Answer:
Molality = 1.46 molal
The freezing point of the solution = -2.72 °C
Explanation:
Step 1: Data given
The freezing point of water H2O is 0.00°C at 1 atmosphere
urea = nonelectrolyte = van't Hoff factor = 1
Mass urea = 13.40 grams
Molar mass urea = 60.1 g/mol
Mass of water = 153.2 grams
Molar mass H2O = 18.02 g/mol
Kf = 1.86 °C/m
Step 2: Calculate moles urea
Moles urea = mass urea /molar mass urea
Moles urea = 13.40 grams / 60.1 g/mol
Moles urea = 0.223 moles
Step 3: Calculate the molality
Molality = moles urea / mass water
Molality = 0.223 moles / 0.1532 kg
Molality = 1.46 molal
Step 4: Calculate the freezing point of the solution
ΔT = i * Kf * m
ΔT = 1* 1.86 °C/m * 1.46 m
ΔT = 2.72 °C
The freezing point = -2.72 °C
