Freezing Point Depression Calculator

How to Use This Calculator

1. Select the solvent name from the dropdown menu. For custom solvents, select "Custom" and enter the name in the provided field.
2. Enter the molar mass of your solute in g/mol.
3. Enter the mass of your solute in grams.
4. Enter the mass of your solvent in kilograms.
5. Enter the freezing point depression constant (K_f) for your solvent. For common solvents, these values are available in reference materials:
• Water: 1.86 °C·kg/mol
• Ethanol: 2.27 °C·kg/mol
• Methanol: 6.84 °C·kg/mol
• Glycerol: 5.12 °C·kg/mol
6. Click the "Calculate" button to compute the molality, freezing point depression, and new freezing point.
7. Use the "Reset" button to clear all inputs and start over.

Understanding the Formula

The freezing point depression (ΔT_f) is calculated using the formula:

ΔT_f = K_f × m

Where:

• ΔT_f is the freezing point depression in degrees Celsius
• K_f is the freezing point depression constant specific to the solvent
• m is the molality of the solution (moles of solute per kilogram of solvent)

Applications

This calculator is useful in various fields:

• Chemistry education for understanding colligative properties
• Industrial applications like antifreeze in car radiators
• Cryopreservation of biological samples
• Food science for preserving foods in cold environments
• Environmental science for studying ice formation in water bodies

Example Calculation

For example, if you dissolve 10 grams of sodium chloride (NaCl, molar mass = 58.44 g/mol) in 500 grams (0.5 kg) of water, and you know that the K_f for water is 1.86 °C·kg/mol, the calculation would be:

1. Calculate moles of NaCl: 10 g / 58.44 g/mol = 0.171 mol
2. Calculate molality: 0.171 mol / 0.5 kg = 0.342 mol/kg
3. Calculate freezing point depression: 1.86 °C·kg/mol × 0.342 mol/kg = 0.637 °C
4. The new freezing point would be 0 °C - 0.637 °C = -0.637 °C