Liquid To solid

  1. Name a substance that will change from liquid state to solid state on heating.
     
  2. jcsd
  3. 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.
     
  4. tiny-tim

    tiny-tim 26,054
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    eggy-weggy :biggrin:
     
  5. The first thing that came to my mind was concrete, but that is a chemical reaction and doesn't really count.

    Is it possible for some sort of solid solution to have a liquid phase at a lower temperature than a solid phase? E.g. one component of the solution precipitates out with increasing temperature while the other component turns to liquid?
     
  6. Mapes

    Mapes 2,532
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    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.
     
  7. DaveC426913

    DaveC426913 16,081
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    You read my mind. :biggrin:
     
  8. Changes chemically :)
     
  9. Andy Resnick

    Andy Resnick 5,785
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    Like!
     
  10. Mapes

    Mapes 2,532
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    Ah, I found it: Plazanet et al., "Freezing on heating of liquid solutions," J Chem Phys 121:5031 p5031 (2004), discussed here. But a look at the subsequent literature indicates that the physics is still being worked out.
     
  11. Interesting, although it sounds like that is still just a chemical reaction, although notably a reversible one.
     
  12. Mapes

    Mapes 2,532
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    Right, or put another way, a multi-component system (with additional factors such as mutual solubility) rather than a single-component system.
     
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