Melting / Freezing Temperature
Melting / Freezing Temperature : As heat is applied to a solid, its temperature will increase until the melting point is reached. More heat then will convert the solid into a liquid with no temperature change. When all the solid has melted, additional heat will raise the temperature of the liquid. The melting temperature of crystalline solids is a characteristic figure and is used to identify pure compounds and elements. Most mixtures and amorphous solids melt over a range of temperatures. The melting temperature of a solid is generally considered to be the same as the freezing point (q.v.) of the corresponding liquid; because a liquid may freeze in different crystal systems and because impurities lower the freezing point, however, the actual freezing point may not be the same as the melting point. Thus, for characterizing a substance, the melting point is preferred. Additional info: As with the melting point, increased pressure usually raises the freezing point. The freezing point is lower than the melting point in the case of mixtures and for certain organic compounds such as fats. As a mixture freezes, the solid that forms first usually has a composition different from that of the liquid, and formation of the solid changes the composition of the remaining liquid, usually in a way that steadily lowers the freezing point
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