I find diverging answers to what the density of nitrogen at standard conditions is. By standard conditions I mean T=273.15 K and P=1 atm (=1.01325 bar).

Different sources state:

  • Wikipedia : 1.2506 g/L
  • Fluidat : 1.250 g/L
  • NIST : 1.2504 g/L
  • When I use ideal gas law : 1.2498 g/L (using molar mass as 28.0134 g/mol and gas constant as 8.31446261815324*10^3 J/(K mol)

Which one is more correct and why ?

  • 2
    $\begingroup$ The first 3 values probably rely either on measurements either on values provided by some of real gas state equations. Try to calculate density from the van der Waals equation, probably by numerical finding the root of the cubic equation. $\endgroup$
    – Poutnik
    Commented May 17, 2021 at 11:55
  • $\begingroup$ Nothing is "more" correct. Something is correct or isn't. $\endgroup$ Commented May 17, 2021 at 12:05
  • 3
    $\begingroup$ Looks identical to me. $\endgroup$ Commented May 17, 2021 at 12:09
  • 1
    $\begingroup$ @NisargBhavsar As this is science, not math, with errors, assumptions, conditions, fuzziness and uncertainties, it is not so much black and white. Gramatically, you are right though, like there is nothing more optimal than optimal. $\endgroup$
    – Poutnik
    Commented May 17, 2021 at 12:36
  • 1
    $\begingroup$ The deviation is in order of one-ten thousandths. So, I'd say, the values are pretty much equal. $\endgroup$ Commented May 20, 2021 at 2:55

1 Answer 1


So if the discrepancies are a cause for concern in your work, check the source given for each measurement to help explain the differences.


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