Why Do Gases Need Same Speed for Thermal Equilibrium?

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Discussion Overview

The discussion centers on the conditions necessary for two gases to achieve thermal equilibrium, specifically addressing the relationship between average molecular speed and average molecular kinetic energy. The scope includes theoretical considerations from kinetic theory and definitions related to thermal equilibrium.

Discussion Character

  • Conceptual clarification, Debate/contested

Main Points Raised

  • One participant asserts that for two gases to be in thermal equilibrium, they must have the same average molecular speed.
  • Another participant suggests that thermal equilibrium is defined by having the same average molecular kinetic energy, noting that gases with different molecular weights will not have the same average speed.
  • A later reply expresses agreement with the second participant's viewpoint, indicating a shared understanding of the relationship between molecular weight and speed.

Areas of Agreement / Disagreement

Participants express differing views on whether gases in thermal equilibrium must have the same average molecular speed or average kinetic energy, indicating that the discussion remains unresolved.

Contextual Notes

The discussion involves assumptions about definitions of thermal equilibrium and kinetic energy, which may not be universally agreed upon or fully explored.

Himanshu_6174
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When two gases are
mixed, if they are to be in thermal equilibrium, they must have the
same average molecular speed. Why or why not?
 
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Himanshu_6174 said:
When two gases are
mixed, if they are to be in thermal equilibrium, they must have the
same average molecular speed. Why or why not?

Actually, they have the same average molecular kinetic energy. If the two gases have different molecular weights, then then they won't have the same average speed; the more massive molecules will be moving slower than the lighter molecules.
 
Thanks stevendaryl, I was thinking the same. Just wanted to confirm :)
 

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