Benedict, Webb and Rubin equation of state

The Benedict, Webb and Rubin equation of state is an empirical equation of state, based on the Beattie-Bridgeman equation of state, which has the following functional form (Eq. A10 of ): \[P= RT\rho + \left( B_0 RT - A_0 - \frac{C_0}{T^2} \right)\rho^2 + (bRT -a)\rho^3 + a \alpha \rho^6 + \frac{c\rho^3 ( 1 + \gamma \rho^2) \exp (-\gamma \rho^2)}{T^2}\] where \(P\) is the pressure, \(T\) is the temperature, \(\rho\) is the density, and \(R\) is the molar gas constant. \(B_0\), \(A_0\), \(C_0\), \(b\), \(a\), \(c\), \(\gamma\) and \(\alpha\) are adjustable parameters.

References

Related reading

• Manson Benedict, George B. Webb, and Louis C. Rubin "An Empirical Equation for Thermodynamic Properties of Light Hydrocarbons and Their Mixtures II. Mixtures of Methane, Ethane, Propane, and n-Butane", Journal of Chemical Physics 10 pp. 747-758 (1942)
• Giorgio S. Soave "An effective modification of the Benedict–Webb–Rubin equation of state",Fluid Phase Equilibria 164 pp. 157-172 (1999)