Ideal Gas Constant: Universal Constant or Relative?

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SUMMARY

The Ideal Gas Constant (R) is often referred to as a universal constant, but its classification is debated among forum participants. While R is derived from Boltzmann's constant (kB) and Avogadro's number (NA), which are indeed universal, the context in which R is applied can vary, particularly when discussing real gases and the Van der Waals equation. Participants emphasized the necessity of experimental determination of constants a and b in the Van der Waals equation, indicating that R's universality may not be absolute in all scenarios.

PREREQUISITES
  • Understanding of the Ideal Gas Law and its applications.
  • Familiarity with Boltzmann's constant (kB) and Avogadro's number (NA).
  • Knowledge of the Van der Waals equation and its constants.
  • Basic principles of thermodynamics and gas behavior.
NEXT STEPS
  • Research the implications of the Van der Waals equation on real gas behavior.
  • Study the derivation and applications of Boltzmann's constant (kB) in thermodynamics.
  • Explore the concept of universal constants in physics and their significance.
  • Investigate experimental methods for determining gas constants in various conditions.
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Chemistry students, physics enthusiasts, and professionals in engineering and thermodynamics who seek to deepen their understanding of gas laws and constants.

bomba923
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Is the Ideal Gas Constant a universal constant?
*If not, then what is it relative to?
 
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I'm not sure what you mean by the Real Gas constant.
The ideal Gas constant R is universal
If you are referring to the vander waal equation that describes real gases and the constants a and b, then no, both a and b are not universal constants. You have to determine a and b experimentally and measure critical temperatures and critical pressures with respect to the compound in question.
 
universal constant, e.g. the speed of light c, where it supposedly holds true at all inertial frames of reference...everywhere.

I don't believe that R is a universal constant.
 
Why isn't R is a universal constant for an ideal gas? When does it ever change?
 
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no I guess not, but before you go on to call it universal (as the speed of light is "universal) you might want to bring it up in one of the physics subforums
 
GCT said:
no I guess not, but before you go on to call it universal (as the speed of light is "universal) you might want to bring it up in one of the physics subforums

!Why--exactly? How what does bringing up it a different forum have to do with the Ideal Gas Constant being universal/"calling it universal"?? :bugeye:
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But I agree, physics and engineering do often use the Ideal Gas Constant, and it easily could have been a question in one of the physics subforums :smile: . I posted this in chemistry because I worked with the Ideal Gas Constant most frequently in my chemistry courses.
 
GCT said:
no I guess not, but before you go on to call it universal (as the speed of light is "universal) you might want to bring it up in one of the physics subforums

To your knowledge

R=k_{B} N_{A}

Boltzmann's constant is universal, Avogadro's number is universal, ergo the ideal gases' constant is universal.

Daniel.
 
Well there you go.

I have to say I'm a bit unfamiliar with so called "universal constants" I've just taken my second semester of physics. I just thought there would be more to the universal constant concept and I didn't think it to be appropriate to accept it simply as some vague notion.
 
  • #10
I pose another question: Will we ever know why all of the "universal" constants are constant? Haha, just kidding around!
 

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