Mathematical equation for the deviation from ideality of real gases

[phantomvommand]

Hi guys,

We have this very common graph where pV deviates from ideality.

May I know the equation for such a curve?

Secondly, if the x-axis were changed to V, what would the graph look like?

 

[BvU]

Check out equation of state
or consult a book like e.g. P.W. Atkins: physical chemistry

$\$

 

[Chestermiller]

View attachment 290237
Hi guys,

We have this very common graph where pV deviates from ideality.

May I know the equation for such a curve?

Secondly, if the x-axis were changed to V, what would the graph look like?

The vertical axis is labelled incorrectly. It should read $$\frac{PV}{RT}$$where V is the molar volume. This is called the compressibility factor Z. According to the Principle of Corresponding States, Z is a function of the reduced pressure $P/P_C$, the reduced temperature $T/T_C$, and the ascentric factor $\omega$, where the subscript C indicates the value at the critical point and where $\omega$ varies with the specific gas. Graphs of Z as a function of reduced temperature, reduced pressure, and ascentric factor can be found in most thermo books.