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Why does the temperature is invariant on phase transitions?

  1. Dec 15, 2015 #1
    Hello there, this is a fact that I can't understand thinking about it... Energy has to be given so that the inter molecular bonds can be broken, and energy goes in when there are formed (even though that sounds very counter intuitive to me), but why is the energy all distributed to potential energy (bonds) and it stops going to kinetic energy in the process?
  2. jcsd
  3. Dec 15, 2015 #2
    Temperature is not kinetic energy! This is only true for an ideal gas.

    Temperature is based on statistics. Two systems have the same temperature when the combined system is in its most probable state. This means that the subsystems have the same relative change in their multiplicity (numbers of microstates) with a small exchange of energy.
  4. Dec 15, 2015 #3
    Maybe another perspective to look into the question is: is it valid to ask, does there exist a phase transition where some other quantity remains unchanged while temperature suddenly drops say?
  5. Dec 15, 2015 #4
    In an adiabatic process, this might happen ...? But for an adiabatic process, can there be a phase transition?
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