Melting Point

For most substances, Melting and Freezing points are equal. For example, the melting point ''and'' freezing point of the Element Mercury is 234.32 Kelvin s (−38.83 °C or −37.89 °F ). However, certain substances possess differing solid-liquid transition temperatures. For example, Agar melts at 85°C (185°F) and solidifies from 32 to 40°C (89.6 to 104°F); this process is known as Hysteresis .

Unlike the Boiling Point , the melting point is relatively insensitive to Pressure .

The melting point of Water is 0°C (32°F, 273 K). In the presence of Nucleating Substances the freezing point of water is the same as the melting point. But in the absence of nucleators water will Supercool to −42°C (−43.6°F, 231 K) before freezing.

Melting points are often used to ascertain the Purity of and to characterise organic compounds. The melting point of a pure substance is always higher than the melting point of that substance when a small amount of an impurity is present. The more impurity is present, the lower the melting point. Eventually, a minimum melting point will be reached. The mixing ratio that results in the lowest possible melting point is known as the Eutectic Point .

The Chemical Element with the highest melting point is Tungsten , at 3695 K (3422°C, 6191°F).

Note: Certain materials, such as Glass , may harden without crystallizing; this is called an Amorphous Solid .

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Melting Point