The amount of chemical substance per unit volume:

$\begin{array}{l}\displaystyle \rho_m = \frac{\nu}{V} = \frac{\rho}{M}= \frac{1}{V_m}\end{array}$

where

$\begin{array}{l}V_m\end{array}$	molar volume of a given substance
$\begin{array}{l}V\end{array}$	volume of a given substance	$\begin{array}{l}\rho\end{array}$	density of a given substance
$\begin{array}{l}\nu\end{array}$	amount of a given substance	$\begin{array}{l}M\end{array}$	molar mass of a given substance

Dimension	SI units	Oil metric units	Oil field units
L^-3	m^-3	cc^-1	ft^-1

Molar Density $\begin{array}{l}\rho_m\end{array}$ is inverse to Molar volume $\begin{array}{l}V_m\end{array}$ :

(1)	$\begin{array}{l}\displaystyle \rho_m = \frac{1}{V_m}\end{array}$

In case of fluid which satisfies Real Gas EOS @model the Molar Density $\begin{array}{l}\rho_m\end{array}$ can be expressed in terms of Z-factor $\begin{array}{l}Z(p, T)\end{array}$ :

(2)	$\begin{array}{l}\displaystyle \rho_m = \frac{p}{ZRT}\end{array}$

where

$\begin{array}{l}T\end{array}$	temperature
$\begin{array}{l}p\end{array}$	pressure
$\begin{array}{l}R\end{array}$	gas constant

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See also

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Molar Density (physical property) = ρm

See also