Kinetic Temperaturea and molecular velocities

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Discussion Overview

The discussion revolves around the concept of kinetic temperature and molecular velocities, particularly in the context of the triple point of water where ice, water, and vapor coexist in equilibrium at a temperature of 273.16 K. Participants explore the relationship between temperature, average kinetic energy, and molecular motion across different phases of matter.

Discussion Character

  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions whether the average kinetic energy of particles is the same in ice, water, and vapor at the triple point.
  • Another participant asserts that at the triple point, it is the chemical potentials of the three phases that are equal, not the kinetic energies.
  • A follow-up post discusses the implications of temperature defined as average kinetic energy and questions whether the mean squared speeds of liquid water and water vapor are the same at the same temperature.
  • Another participant introduces a vague inquiry about the nature of kinetic temperature and its relation to molecular movement, suggesting there may be other factors involved.

Areas of Agreement / Disagreement

Participants express differing views on the relationship between kinetic energy and temperature across phases, with no consensus reached on whether average kinetic energies are equal or if other factors are at play.

Contextual Notes

There are unresolved assumptions regarding the definitions of kinetic temperature and the implications of molecular motion in different states of matter.

mrcotton
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If I have ice, water and vapour at the triple point and they are in equilibrium at a temperature of 273.16. Does this mean that the average kinetic energy of the particles is the same in each state? If so how can the molecules in the water be moving with the same mean squared speed as the molecules in the vapour? Thanks for any help
 
Last edited:
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At the triple point, it is not he kinetic energies which are equal, but the chemical potentials ##\mu## of the 3 phases of matter.
 
Thanks for responding Matterwave

LatentHeat1_zps76e36554.jpg


Where this question has come from is a discussion I was having about temperature increase as water changes from the solid to the gaseous state. As the water changes from D to E, If temperature is defined as average KE =3/2kT does this imply that the KE and hence the translational mean squared speeds of the liquid at D and the gas at E are the same if they are at the same temperature?
 
Does kinetic temperature real because of molecular moving?
Hint: something else moving?
 

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