One of the cubic equations of real gas state defining the Compressibility factor as a function of Gas pressure and Gas temperature :

Z^3 - (1-B) \, Z^2 +(A-2B-3B^2) \, Z -(AB-B^2-B^3) = 0

A=\frac{a \, \alpha \, p}{ R^2 \, T^2}

B=\frac{b \, p}{ R \, T}

a = 0.45724 \cdot \frac{R^2 \, T_c^2}{p_c}

b = 0.07780 \cdot \frac{R \, T_c}{p_c}

\alpha = \left( 1 + \kappa \, (1-T_r^{0.5}) \right)^2

\kappa = 0.37464 + 1.54226 \, \omega -0.26992 \, \omega^2

where

where

	Gas density		Gas pressure		Gas molar mass
	Compressibility factor		Gas temperature		Gas constant

See also