0
$\begingroup$

In $PV=nRT$, $n$ is degrees of freedom. While in $PV=Nk_BT$, N is number of moles in a molecule. So value of $n$ is $3$, $5$ and $6$ for monatomic, diatomic and polyatomic respectively. But in the video, he wrote that $n=1$ for monatomic. Isn't that a wrong assumption?

$\endgroup$
2
  • 1
    $\begingroup$ You have several errors in your post. N is the number of molecules, n is the number of moles. "The number of moles in a molecule" is nonsense. $\endgroup$
    – nasu
    Commented Feb 11, 2022 at 12:31
  • $\begingroup$ You've completely misunderstood the terms "n" and "N". $\endgroup$
    – Cross
    Commented Feb 11, 2022 at 12:35

1 Answer 1

1
$\begingroup$

In the ideal gas law $$PV=nRT$$ $n$ is not the degrees of freedom. Instead $n$ is the number of molecules (measured in mol). You can see this also from the unit of the gas constant $$R=8.314 \text{ m}^3\text{ Pa}\text{ K}^{-1}\text{ mol}^{-1}$$

$\endgroup$
1
  • $\begingroup$ Oops, $f$ is degrees of freedom. $\endgroup$
    – Man
    Commented Feb 11, 2022 at 12:39

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.