Answer to Question #93932 in Physical Chemistry for Abhishek

Question

State the principle of corresponding states.

Answer 1

The principle of corresponding states was declared by Diderik van der Waals in 1873 as a theorem that states the equality of a compression factor for all kind of gases. Some more general statement the theorem claims that any kind of the substance possesses exactly the same state equation in case, when the state parameters are defined as reduced to the critical parameters (T_c, P_c and V_c).

$\frac{pV_{m}}{RT}=F(V_{r}, T_{r})$ - compression factor

As for the real gases the theorem has only limited application:

1) In case of the classical mechanics;

2) Molecules are spherical;

3) Intramolecular freedom parameters are not related to the specific volume of the molecule;

4) Potential energy is defined with intermolecular distances only;

5) Interaction potential is defined as $ef(\frac{r}{sigma})$