How to Calculate Freezing Point Depression (ΔTf)
Calculate freezing point lowering step-by-step:
Enter Molality (m)
Input solute molal concentration in mol/kg.
Enter Kf Constant
Input cryoscopic constant Kf (°C/m) for the solvent (1.86 °C/m for water).
Enter van 't Hoff (i)
Input ion count factor i (i=2 for NaCl, i=3 for CaCl₂).
Compute ΔTf
Multiply ΔTf = i × Kf × m and subtract from pure freezing point.
Key Features & Cryoscopic Physics
De-Icing & Antifreeze Engine
Computes exact freezing protection temperatures for road salts and engine coolants.
Cryoscopic Database
Includes standard Kf constants for water (1.86), benzene (5.12), and camphor (40.0).
Dual Unit Temperature
Displays new freezing point in Celsius and Fahrenheit.
Physical Chemistry Guide: Freezing Point Depression
Freezing Point Depression (ΔTf) occurs when solute particles disrupt the formation of an organized solvent crystal lattice:ΔTf = i × Kf × mThe new freezing point of the solution is: Tf(solution) = Tf(pure) - ΔTf.
Frequently Asked Questions
?Why is CaCl₂ more effective than NaCl for melting ice?
CaCl₂ dissociates into 3 ions (Ca²⁺ + 2Cl⁻, i = 3), producing 50% more particles per mole than NaCl (i = 2), causing a greater freezing point depression per mole.