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sam013024
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Name a substance that will change from liquid state to solid state on heating.
Bloodthunder said:And remaining chemically unchanged? Nothing does that.
You could have your ceramics which change from a liquid structure to a solid structure, but that's with the formation of bonds on heating and all that.
QuantumPion said:Is it possible for some sort of solid solution to have a liquid phase at a lower temperature than a solid phase?
tiny-tim said:eggy-weggy
tiny-tim said:eggy-weggy
Mapes said:It is possible, even for reversible transformations. It's only required that the high-temperature phase (the solid) has a higher entropy than the low-temperature phase (the liquid). As you can imagine, this is pretty unusual. I seem to remember that it's been demonstrated in some carefully designed polymer systems, though. Will look to see if I can find the details.
Mapes said:Ah, I found it: Plazanet et al., "Freezing on heating of liquid solutions," J Chem Phys 121:5031 p5031 (2004), discussed http://physicsworld.com/cws/article/news/20325" . But a look at the subsequent literature indicates that the physics is still being worked out.
QuantumPion said:Interesting, although it sounds like that is still just a chemical reaction
Melting point is the temperature at which a solid substance changes to a liquid state. It is the temperature at which the molecules of a substance have enough energy to overcome their attractive forces and move freely as a liquid.
As heat is added to a substance, the molecules gain more energy and begin to vibrate faster, causing the attractive forces between them to weaken. This results in a lower melting point, meaning the substance will change from a solid to a liquid at a lower temperature.
The melting point of a substance is a unique physical property that can help identify and distinguish it from other substances. It can also provide information about the purity of a substance, as impurities can affect the melting point.
Yes, the melting point of a substance can change depending on external factors such as pressure and the presence of impurities. However, the melting point of a pure substance remains constant under standard conditions.
The melting point of a substance can be measured using a variety of methods, including melting point apparatus, differential scanning calorimetry, and capillary tube method. These methods involve heating the substance and recording the temperature at which it changes from a solid to a liquid.