Problem: Radiator coolant is often a 50/50 % by volume mixture of ethylene glycol, HOCH2CH2OH (62.1 g/mol), and water. At 20°C, the density of ethylene glycol is 1.1088 g/mL and the density of water is 0.9982 g/mL. Assuming that the volumes are additive, what is the expected freezing point (°C) of a 50/50(v/v)% ethylene glycol/water solution? Kf = 1.86°C/m for water. Enter your answer as the nearest whole number with no units.a. 100.53°Cb. 101.23°Cc. 100.08°Cd. 103.91°Ce. 100.31°C

FREE Expert Solution

We’re being asked to calculate for the freezing point of an aqueous solution containing 50% (v/v) ethylene glycol

Recall that the freezing point of a solution is lower than that of the pure solvent and the change in freezing point (ΔT­f) is given by:


ΔTf=ΔTf, solution-ΔTf, pure solvent



The change in freezing point is also related to the molality of the solution:


ΔTf=i Kf m


where: 

i = van’t Hoff factor

m = molality of the solution (in m or mol/kg)

Kf = freezing point depression constant (in ˚C/m)



We need to convert the 50% (v/v) of ethylene glycol to molality. Recall that the molality of a solution is given by:


Molality (m)=moles of soluteKilograms of solvent


We will calculate the freezing point of the solution using the following steps:

Step 1. Determine the composition of the solution.
Step 2. Calculate the moles of the solute.
Step 3. Calculate the mass of the solvent (in kg).
Step 4. Calculate the molality of the solution.
Step 5. Calculate the freezing point of the solution


Step 1. Determine the composition of the solution.

View Complete Written Solution
Problem Details

Radiator coolant is often a 50/50 % by volume mixture of ethylene glycol, HOCH2CH2OH (62.1 g/mol), and water. At 20°C, the density of ethylene glycol is 1.1088 g/mL and the density of water is 0.9982 g/mL. Assuming that the volumes are additive, what is the expected freezing point (°C) of a 50/50(v/v)% ethylene glycol/water solution? Kf = 1.86°C/m for water. Enter your answer as the nearest whole number with no units.

a. 100.53°C

b. 101.23°C

c. 100.08°C

d. 103.91°C

e. 100.31°C


Frequently Asked Questions

What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Freezing Point Depression concept. If you need more Freezing Point Depression practice, you can also practice Freezing Point Depression practice problems.

What is the difficulty of this problem?

Our tutors rated the difficulty ofRadiator coolant is often a 50/50 % by volume mixture of eth...as high difficulty.