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Fractional freezing is a process used in process engineering and chemistry to separate substances with different melting points. It can be done by partial melting of a solid, for example in zone refining of silicon or metals, or by partial crystallization of a liquid, as in freeze distillation, also called normal freezing or progressive freezing.
In the liquid solution, the solvent is diluted by the addition of a solute, so that fewer molecules are available to freeze (a lower concentration of solvent exists in a solution versus pure solvent). Re-establishment of equilibrium is achieved at a lower temperature at which the rate of freezing becomes equal to the rate of liquefying.
The freezing point depression osmometer is an osmometer that is used in determining a solution's osmotic concentration as its osmotically active aspects depress its freezing point. In the past, freezing point osmometry has been used to assess the osmotic strength of colloids and solutions. The osmometer uses the solution's freezing point ...
It is cheap, nontoxic, and has a high heat capacity. It however has only a 100 Kelvin liquid range, and it expands upon freezing. To address these problems, alternative coolants with improved properties were developed. Freezing and boiling points are colligative properties of a solution, which depend on the concentration of dissolved substances ...
Freeze drying, also known as lyophilization or cryodesiccation, is a low temperature dehydration process [1] that involves freezing the product and lowering pressure, ...
Most liquids freeze by crystallization, formation of crystalline solid from the uniform liquid. This is a first-order thermodynamic phase transition, which means that as long as solid and liquid coexist, the temperature of the whole system remains very nearly equal to the melting point due to the slow removal of heat when in contact with air, which is a poor heat conductor.
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Water freezes at 0 °C. However, a mixture of 70 percent deicing fluid and 30 percent water freezes below −55 °C. This is known as the eutectic concentration, where the freezing point of the mixture is at its lowest point, and lower than either of the component substances.