Enter the cryoscopic constant, molality, and the Van’t Hoff Factor into the calculator to determine the freezing point depression.

Freezing Point Depression Formula

The following formula is used to calculate a freezing point depression: 

Tf = Kf * b * i
  • Where Tf is the freezing point depression
  • Kf is the cryoscopic constant
  • b is the molality
  • i is the Van’t Hoff factor

To calculate the freezing point depression, multiply the cryoscopic constant by the molality and the Van’t Hoff factor.

What is a freezing point depression?

Definition:

A freezing point depression is a property observed in solutions that describes the effect of a solution’s freezing point being lower than that of a pure solvent.

The freezing point is directly related to the molality of the solute.

How to calculate freezing point depression?

The following example outlines the steps needed to calculate a freezing point depression.

First, determine the cryoscopic constant. In this case, the cryoscopic constant is found to be 5.

Next, determine the molality. In this example, the molality is measured to be 10.

Next, determine the Van’t Hoff Factor. For this problem, the Van’t Hoff Factor is calculated to be .50.

Finally, calculate the freezing point depression using the formula above:

Tf = Kf * b * i

Tf = 5*10 *.50

Tf = 25