Determine the freezing point of a solution which contains 0.31 mol of sucrose in 175 g of water. K_f = 1.86$\degree$C/m A) 3.3$\degree$C B) 1.1$\degree$C C) 0.0$\degree$C D) -1.1$\degree$C E) -3.3$\degree$C

Question

Quizplus · Accepted Answer

First, calculate the molality of the solution:
molality = 0.31 mol / 0.175 kg = 1.77 mol/kg

Then, use the freezing point depression equation:
ΔTf = Ks x molality
ΔTf = 1.86 °C/m x 1.77 mol/kg
ΔTf = 3.3 °C

The freezing point depression is equal to the amount by which the freezing point decreases relative to pure solvent, so the freezing point of the solution will be:
Freezing point of solution = Freezing point of pure solvent - ΔTf

For water, the freezing point is 0°C, so:
Freezing point of solution = 0°C - 3.3°C
Freezing point of solution = -3.3°C

Therefore, the best answer choice is E, -3.3°F.

Determine the Freezing Point of a Solution Which Contains 0 °\degree°

Determine the Freezing Point of a Solution Which Contains 0 $\degree$