Question

An antifreeze solution is prepared by dissolving 31 g of ethylene glycol in 600 g of water. Calculate the freezing point of the solution (kf of water).

a. -1.86°C
b. -2.23°C
c. -3.84°C
d. -4.22°C

Answer 1

To calculate the freezing point of the antifreeze solution, we need to use the equation: ΔT = kf · m. First, we calculate the molality. Finally, we calculate the freezing point depression and get -1.54°C.

Step-by-step explanation:

To calculate the freezing point of the antifreeze solution, we need to use the equation: ∊T = kf · m, where ∊T is the change in freezing point, kf is the freezing point depression constant for water (-1.86°C/m), and m is the molality of the solution.

First, we calculate the molality:

Molality = moles of solute / mass of solvent in kg

For ethylene glycol, we first calculate the moles:

Moles of ethylene glycol = mass / molar mass = 31 g / 62.07 g/mol = 0.50 mol

Next, we convert the mass of water to kg:

Mass of water = 600 g / 1000 = 0.60 kg

Now we can calculate the molality:

Molality = 0.50 mol / 0.60 kg = 0.83 m

Finally, we calculate the freezing point depression:

∊T = kf · m = -1.86°C/m · 0.83 m = -1.54°C

Therefore, the freezing point of the solution is -1.54°C.