The melting point of water at 1 atmosphere of pressure is 0 °C (32 °F, 273.15 K), this is also known as the ice point. 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 can supercool to −42 °C (−43.6 °F, 231 K) before freezing.
Unlike the boiling point, the melting point is relatively insensitive to pressure. Melting points are often used to characterise organic compounds and to ascertain the purity. 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, 6192 °F). The often-cited carbon does not melt at ambient pressure but sublimates at about 4000 K; a liquid phase only exists above pressures of 10 MPa and estimated 4300–4700 K. Tantalum hafnium carbide (Ta4HfC5) is a refractory compound with a very high melting point of 4488 K (4215 °C, 7619 °F).[1] At the other end of the scale, helium does not freeze at all at normal pressure, even at temperatures infinitesimally close to absolute zero; pressures over 20 times normal atmospheric pressure are necessary.
2006-12-04 22:18:38
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answer #1
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answered by richy 2
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At standard atmospheric pressure of 1 atm, the ice will normally melt at 0 degree celsius. During the melting process the temperature of will remain constant at this degree. This is because, heat is used up to break away the molecular attractions between each molecule.
2006-12-05 06:40:44
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answer #2
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answered by Anonymous
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The melting point of water is 0 °C (32 °F, 273.15 K) @ 1 atm pressure. This whole concept is known as Heat of Fusion. It's the amount of thermal energy which must be absorbed or evolved for 1 mole of a substance to change states from a solid to a liquid or vice versa.
2006-12-05 09:55:23
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answer #3
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answered by yessenia 3
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32 F or 0 C
2006-12-05 06:27:29
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answer #4
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answered by xox_bass_player_xox 6
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Just above the freezing temp.
2006-12-05 06:12:45
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answer #5
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answered by U can't b serious 4
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