Understanding Entropy and Equilibrium: Debunking the Confusion

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    Entropy Equilibrium
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Discussion Overview

The discussion revolves around the concept of entropy and equilibrium, specifically addressing apparent contradictions in textbook definitions regarding the entropy of the universe at equilibrium. Participants explore the implications of these definitions in both theoretical and conceptual contexts.

Discussion Character

  • Debate/contested

Main Points Raised

  • One participant expresses confusion about whether the entropy of the universe is zero or maximum at equilibrium, citing conflicting statements from their textbook.
  • Another participant argues that at equilibrium, entropy is at its maximum, suggesting that while it remains constant, it reflects the highest state of entropy for the system considered as the universe.
  • A third participant proposes that the textbook may be referring to the change in entropy (dS) being zero for small changes in a system at equilibrium, rather than the absolute value of entropy (S).
  • A later reply agrees with this interpretation, indicating that the confusion may stem from a misunderstanding of the terminology used in the textbook.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the interpretation of entropy at equilibrium, with multiple competing views and interpretations remaining present in the discussion.

Contextual Notes

There is ambiguity regarding the definitions of entropy and equilibrium as presented in the textbook, particularly in distinguishing between absolute entropy values and changes in entropy. The discussion highlights the need for clarity in terminology.

jisun.hong
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I'm so confused.
So my textbook tells me that entropy of the universe is equal to zero at equilibrium.
And then later on it tells me at equilibrium the universe achieves maximum entropy.
So is it zero or max?
Thanks for the help.
 
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Maximum since entropy tends to increase. So if you have a system at equilibrium it means that its entropy remains constant, but as entropy tends to increase it means that the entropy of the system is at its maximum. It seems that your book take the whole universe as a system, so replace "system" by "universe" in my post and all is fine.
 
Could your book have said that the change in entropy (mathematically, dS rather than S) is zero for small changes to a system in equilibrium?
 
Mapes said:
Could your book have said that the change in entropy (mathematically, dS rather than S) is zero for small changes to a system in equilibrium?
Good catch Mapes :) Must be this.
 

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