Compressibility factor

The compressibility factor, $Z$, is given by

$Z={\frac {pV}{Nk_{B}T}}$

where p is the pressure, V is the volume, $k_{B}$ is the Boltzmann constant, T is the temperature and N is the number of molecules.

Compressibility factor of an Ideal Gas

From the ideal gas law we see that

$Z={\frac {pV}{Nk_{B}T}}=1$