Crystallization Temperature – The temperature at which aqueous solutions crystallize when super cooled.
Freezing Point/Melting Point – The temperature at which the liquid and solid phases of a substance remain together in equilibrium. Both are the same temperature, however the measuring technique differs.
Freezing Point Depression – The freezing point of a solvent lowers when a solute is added to aqueous solutions. One mole (1 Osmol) of solute per kilogram of water depresses the freezing point by 1.85° C.
Freezing Point Plateau – The constant temperature maintained during the time that ice and liquid exist in isothermal equilibrium after crystallization occurs.
Heat of Fusion –The heat released when a super-cooled liquid crystallizes. The crystallization process considerably reduces the random molecular motion of the liquid state. The loss of molecular energy is released as heat. This heat of “putting together” warms the solution, causing the paradox of sample warming during freezing. For water, 80 calories of heat are released for every gram that turns from liquid to solid.
Super-cooling – The tendency of any solvent or solution to remain in a liquid state when cooled below its freezing point. The greater the amount of super-cooling, the less stable the liquid and the more likely it is to crystallize spontaneously. It corresponds, in a sense, to supersaturation of solute in a solvent.
Thermodynamics – The study of heat transfer, with respect to measuring a freezing point. It is an analysis of all factors that affect heat flow into, from and within a sample.