Understanding Boiling Point Elevation: Real Gas Law and Its Impact on Molecules

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SUMMARY

The discussion centers on the ideal gas law and its modification into the real gas law, specifically addressing the equation (P + n²a/v²)(V - nb) = nRT. Participants explore the relationship between boiling point elevation and molecular size, concluding that larger molecules inhibit the vaporization of liquid atoms, thereby increasing boiling points. The conversation highlights the significance of colligative properties and their dependence on solute particle quantity, particularly in the context of macromolecules, referencing the Flory-Huggins theory for further understanding.

PREREQUISITES
  • Understanding of the Ideal Gas Law and Real Gas Law
  • Familiarity with colligative properties in chemistry
  • Knowledge of molecular size effects on physical properties
  • Basic comprehension of the Flory-Huggins solution theory
NEXT STEPS
  • Study the implications of the Flory-Huggins theory on macromolecular solutions
  • Explore the relationship between molecular size and boiling point elevation
  • Investigate the experimental determination of constants 'a' and 'b' in the real gas law
  • Learn about colligative properties and their applications in various chemical contexts
USEFUL FOR

Chemistry students, researchers in physical chemistry, and professionals studying the behavior of macromolecules in solutions will benefit from this discussion.

Biker
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So was thinking a little bit about the ideal gas law.
##P V = n R T##
And I read an article about the real gas law where they just edited few properties.
##(P + \frac{n^2 a}{v^2}) (V - nb) = n R T ##
Where a and b are constant determined experimentally.

So going back to our original point, Why doesn't the boiling point elevation have something related to the volume of the molecules or atoms?

And we know that the boiling point increases because of how the molecules prevent some of the liquid atoms to change into vapor state which reduces the vapor pressure in result increasing the boiling point.

So if we believe that this is what actually happen then bigger molecules/atoms will prevent more of the liquid atoms to change into vapor state which increases the boiling point.

What is happening here?

P.s I know that colligative properties only depend on how many solute particles.
 
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DrDu said:
These effects exist but the boiling point increase is usually reported for infinite dilution where solutions behave ideally.
But for macromolecules, these effects become very important, cf. the Flory Huggins theory:
https://en.wikipedia.org/wiki/Flory–Huggins_solution_theory
Oh that is actually great. Didn't know that there is a theory already there. Thank you!
 
Not completely related, but ...
 

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