Calculation of molar conductance at infinite dilution

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SUMMARY

The calculation of molar conductance at infinite dilution yields a value of 524*10^4, achieved through the addition of partial pressures. The discussion highlights the confusion surrounding intensive properties, specifically whether they can be added algebraically. It clarifies that while intensive properties such as molar conductivity cannot be directly summed, the total pressure of a gas mixture can be derived from the partial pressures multiplied by their respective mole fractions. This distinction is crucial for understanding the relationship between intensive and extensive properties.

PREREQUISITES
  • Understanding of intensive and extensive properties in thermodynamics
  • Familiarity with gas laws and partial pressures
  • Basic knowledge of molar conductance and its significance
  • Ability to interpret scientific literature, such as "Intensive and Extensive Properties" by Redlich
NEXT STEPS
  • Research the definitions and examples of intensive and extensive properties in detail
  • Study the relationship between partial pressures and total pressure in gas mixtures
  • Examine the concept of molar conductance and its calculation methods
  • Read the paper "Intensive and Extensive Properties" J. Chem. Educ., 1970, for deeper insights
USEFUL FOR

Chemistry students, educators, and professionals in the field of physical chemistry who seek to clarify the concepts of intensive and extensive properties and their applications in calculations involving gas mixtures and molar conductance.

Zayan
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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.
 
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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
 

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Without a context, I can't say.
 
Looks a bit like answer from ChatGPT: definitive, authoritative, polite - and incorrect :wink:
 
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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).
 

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