Freezing Point Depression Calculator
Calculate freezing point change: delta_Tf = Kf x m x i.
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Enter the cryoscopic constant (Kf) of the solvent, the molality of the solution, and the van't Hoff factor. For water, Kf = 1.86 C/m. The calculator computes delta_Tf = Kf x m x i.
About the Freezing Point Depression Calculator
Freezing point depression is a colligative property: the freezing point of a solution is lower than that of the pure solvent. Like boiling point elevation, it depends on the total number of solute particles. It is the principle behind road salting, antifreeze, and molar mass determination by cryoscopy.
Frequently Asked Questions
What is Kf for water?
The cryoscopic constant for water is 1.86 C/m. Other common values: benzene 5.12, acetic acid 3.90, camphor 37.7 (which is why camphor is often used in molar mass determination).
Why does salt lower the freezing point of water?
Dissolved salt particles interfere with the formation of the crystalline ice structure. The solution must be cooled further before the solvent molecules can organize into a solid, lowering the freezing point.
How is this used in everyday life?
Road salt lowers the freezing point of water on roads, preventing ice formation. Antifreeze (ethylene glycol) in car radiators lowers the freezing point of coolant to prevent engine damage in winter.