How to use the freezing point depression calculator
Find how a solute lowers the freezing point. Enter van 't hoff factor, molality, kf of solvent in the fields above; the freezing point drop, new freezing point (water) are computed instantly and plotted on the chart so you can see how the answer changes.
Formula
Variables
- i — van 't Hoff factor
- m — Molality (mol/kg)
- Kf — Kf of solvent (°C·kg/mol)
Worked example
With van 't hoff factor = 2, molality = 1 mol/kg, kf of solvent = 1.86 °C·kg/mol, the calculator gives freezing point drop ≈ 3.72 °C; new freezing point (water) ≈ -3.72 °C.
Frequently asked questions
What is the formula for the freezing point depression calculation?
Freezing point drop (°C) = i × Kf × m. New freezing point (water) (°C) = -[Freezing point drop]. Here i is van 't hoff factor, m is molality (mol/kg), Kf is kf of solvent (°C·kg/mol).
What inputs do I need for the freezing point depression calculator?
You need van 't hoff factor, molality in mol/kg, kf of solvent in °C·kg/mol. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use this calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.