Calculation of molar conductance at infinite dilution

Click For Summary

Discussion Overview

The discussion revolves around the calculation of molar conductance at infinite dilution and the nature of intensive properties in relation to their addition or subtraction. Participants explore the implications of treating intensive properties in calculations, particularly in the context of molar conductivity and related concepts in thermodynamics.

Discussion Character

  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant questions the addition of molar conductivity values, suggesting that it is an intensive property and should not be added.
  • Another participant challenges this notion, arguing that intensive properties can be related through other means, using the example of total pressure and partial pressures in gas mixtures.
  • A further reply emphasizes that while partial pressures can be added in a specific way, intensive properties cannot be directly summed algebraically.
  • One participant expresses confusion about textbook definitions of intensive properties and their addition, seeking clarification on the conditions under which this might be valid.
  • Another participant notes the complexity of the distinction between intensive and extensive properties, referencing a specific academic paper that discusses these concepts.

Areas of Agreement / Disagreement

Participants do not reach a consensus on whether intensive properties can be added. Multiple competing views remain regarding the treatment of intensive properties in calculations.

Contextual Notes

Participants highlight the ambiguity in definitions and the conditions under which intensive properties might be treated differently, indicating a need for further context to clarify the discussion.

Zayan
Messages
63
Reaction score
7
Homework Statement
At25C, the molar conductances at infinite
dilution for the strong electrolytes
NaOH, NaCl and BaCl2are
248x10^-4,126x10^-4 and
280x 10^-4Sm mol1 respectively,
XmBa(OH)2 in Sm mol-1 is
Relevant Equations
Using algebra
The answer given is 524*10^4. The process used is by adding/subtracting the values given. But my concern is that isn't molar conductivity an intensive property? And it hence can't be added. So how is it added and the answer obtained.
 
Physics news on Phys.org
Who says intensive properties can't be added? How is the total pressure of a gas mixture related to the partial pressures of its components?
 
mjc123 said:
Who says intensive properties can't be added? How is the total pressure of a gas mixture related to the partial pressures of its components?
Partial pressure times the mole fraction is added to get total pressure. Not partial pressure separately. Intensive properties can't directly algebraically be added so why is it here?
 
Not so. If the partial pressure of oxygen is 0.2 bar, and the partial pressure of nitrogen is 0.8 bar, the total pressure is 1 bar.

You are perhaps thinking of Pi = xiPtot
But Ptot = P1 + P2
= x1Ptot + x2Ptot

But Ptot ≠ x1P1 + x2P2
 
Oh you're right but why does my textbook and even google say that intensive properties (like electrode potential) can't be algebraically added or subtracted
 

Attachments

  • Screenshot_2024-09-17-20-08-57-39_40deb401b9ffe8e1df2f1cc5ba480b12.jpg
    Screenshot_2024-09-17-20-08-57-39_40deb401b9ffe8e1df2f1cc5ba480b12.jpg
    18.9 KB · Views: 87
Without a context, I can't say.
 
Looks a bit like answer from ChatGPT: definitive, authoritative, polite - and incorrect :wink:
 
  • Like
Likes   Reactions: PhDeezNutz and jim mcnamara
So
Borek said:
Looks a bit like answer from ChatGPT: definitive, authoritative, polite - and incorrect :wink:
Do you mean intensive properties can be added? If yes, what are the conditions?
 
Zayan said:
Do you mean intensive properties can be added? If yes, what are the conditions?

From the quick googling you are not the first to ask that question and the discussion is not new, problem is with the division extensive/intensive which is not as good and clear as it sounds to be. Compare Redlich, "Intensive and Extensive Properties" J. Chem. Educ., 1970, 47 (2), 154–156 (can be found as a downloadable pdf).
 

Similar threads

  • · Replies 0 ·
Replies
0
Views
2K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 11 ·
Replies
11
Views
5K
  • · Replies 2 ·
Replies
2
Views
3K
Replies
1
Views
5K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 4 ·
Replies
4
Views
17K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 8 ·
Replies
8
Views
4K