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Does the critical temperature of a gas depend on the amount of the gas taken? Or is it independent of it? My book does not specify this point.

I think according to the gas laws, the critical temperature should depend on the amount of gas taken. Am I correct?

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    $\begingroup$ Critical parameters are intensive properties, independent on the system scaling. $\endgroup$
    – Poutnik
    May 26, 2021 at 6:12

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I don’t think you're correct. The critical values (pressure, volume and temperature) are the properties of a gas and they don’t depend on how many moles of the gas you have. It's also evident from the formula of critical temperature:

$$T_\mathrm{c} = \frac{8a}{27Rb},$$

where $a,$ $b$ and $R$ are constant for the gas. There is no dependency on the amount of substance.

Further, you don’t find any data on the amount of a gas when you look for the value of it’s critical temperature. For example in table 3.10 here.

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  • $\begingroup$ Critical volume is defined for one mole of the gas at critical temperature, but it's formula is : $3b$. So I am not sure we can base our arguments on these formulae. $\endgroup$
    – Alpha Delta
    May 26, 2021 at 4:23
  • $\begingroup$ I’m not completely sure but I think critical volume is defined for 1 mol because volume increases with an increase in no. of moles of the gas whereas temperature doesn’t. So we need to define critical volume for a certain quantity, i.e. 1 mol, but the same doesn’t apply on critical temperature. But again, this is my hypothesis which I haven’t cross checked anywhere. $\endgroup$
    – WhySee
    May 26, 2021 at 4:38

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