View source for Redlich Kwong EOS in FPROPS

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Work on this continues as part of GSoC 2011 ([[User:richardTowers|Richard Towers]]). See also [[FPROPS]], [[PengRobinson EOS in FPROPS]].
==Overview==
The Redlich-Kwong equation of state is one of several cubic equations of state that FPROPS aims to implement in the future. In its basic form it relates pressure to temperature and relative volume:

<math>
\begin{align}
P=\frac{RT}{V-b}-\frac{a}{V(V+b)}
\end{align}
</math>

==Departure Functions==
Other thermodynamic properties can be calculated from the departure functions:

<math>
\begin{align}
A-A^{0}=-RT\ln\frac{V-b}{V}-\frac{a}{b}\ln\frac{V+b}{V}-RT\ln\frac{V}{V^{0}}
\end{align}
</math>

<math>
\begin{align}
S-S^{0}=R\ln\frac{V-b}{V}-\frac{a}{2bT}\ln\frac{V+b}{V}+R\ln\frac{V}{V^{0}}
\end{align}
</math>

<math>
\begin{align}
H-H^{0}=\frac{bRT}{V-b}-\frac{a}{V+b}-\frac{3a}{2b}\ln\frac{V+b}{V}
\end{align}
</math>

<math>
\begin{align}
U-U^{0}=-\frac{3a}{2b}\ln\frac{V+b}{V}
\end{align}
</math>

<math>
\begin{align}
G-G^{0}=\frac{bRT}{V-b}-\frac{a}{V+b}-RT\ln\frac{V-b}{V}-\frac{a}{b}\ln\frac{V+b}{V}-RT\ln\frac{V}{V^{0}}
\end{align}
</math>

<math>
\begin{align}
\ln\frac{f}{P}=\frac{b}{V-b}-\frac{a}{RT(V+b)}-\ln\frac{V-b}{V}-\frac{a}{bRT}\ln\frac{V+b}{V}-\ln\left(\frac{V}{V-b}-\frac{a}{RT(V+b)}\right)
\end{align}
</math>