Molecule N2o4 has a greater entropy than NO2

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    Entropy Molecule
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Discussion Overview

The discussion revolves around the entropy of gases, specifically comparing the entropy of N2O4 and NO2, and the implications of mole quantity on entropy. Participants explore the validity of statements regarding entropy changes in reactions and the nature of entropy as an extensive property.

Discussion Character

  • Homework-related, Debate/contested, Conceptual clarification

Main Points Raised

  • One participant questions why the statement about two moles having twice the entropy is considered false, suggesting that the number of moles should matter.
  • Another participant asserts that the statement is not false, emphasizing that entropy is an extensive variable.
  • A different participant raises a concern that having more moles in the same conditions might decrease entropy, indicating a potential misunderstanding of entropy behavior.
  • A subsequent reply simply refutes the concern without further elaboration.

Areas of Agreement / Disagreement

Participants express differing views on the relationship between the number of moles and entropy, with some asserting that entropy is extensive while others question this notion. The discussion remains unresolved regarding the implications of mole quantity on entropy.

Contextual Notes

There are unresolved assumptions regarding the definitions of entropy and the conditions under which the statements are evaluated. The discussion does not clarify the specific context of the entropy change for the reaction mentioned.

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Homework Statement



Why is this statement false?

'Two moles of a substance at temperature T and pressure p has twice the entropy of one mole of the same substance at the same temperature and pressure.'
--> Is it because the number of moles doesn't matter. Why doesn't it?

Why is this statement true?

'The entropy change for the reaction N2O4(g) -> 2 NO2(g) is positive.'
--> The molecule N2o4 has a greater entropy than NO2, so it delta S, change in entropy would be entropy of NO2 - entropy of N2O4, which would be a negative (smaller - bigger number)? Am I going about this wrong?
 
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a.a said:
Why is this statement false?

'Two moles of a substance at temperature T and pressure p has twice the entropy of one mole of the same substance at the same temperature and pressure.'


It's not false; entropy is an extensive variable.
 


If there are more moles in the same place under the same tempreature and pressure, wouldn't that decrease the entropy?
 


Nope.
 

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