Compressibility factor is deviation from ideal gas

The compressibility factor (also called the compression factor or gas deviation factor) quantifies how far a real gas departs from ideal-gas behaviour.

Notation:

1. \(R\) (R) is molar_gas_constant.

Conditions:

1. The gas sample is at thermodynamic equilibrium.

Notes:

1. Can be equivalently defined as the ratio of the molar volume \(V/n\) of the real gas to the molar volume \(RT/\rho\) of the corresponding ideal gas at the same temperature and pressure.

2. \(Z = 1\) corresponds to ideal-gas behaviour.

3. At high pressures repulsive interactions dominate, giving \(Z > 1\).

4. At low pressures attractive interactions dominate, giving \(Z < 1\).

Links:

1. Wikipedia – Compressibility factor

compressibility_factor

compressibility_factor of the real gas.

Symbol:

Z

Latex:

\(Z\)

Dimension:

dimensionless

pressure

pressure of the gas.

Symbol:

p

Latex:

\(p\)

Dimension:

pressure

volume

volume of the gas.

Symbol:

V

Latex:

\(V\)

Dimension:

volume

amount_of_substance

amount_of_substance of the gas.

Symbol:

n

Latex:

\(n\)

Dimension:

amount_of_substance

temperature

temperature of the gas.

Symbol:

T

Latex:

\(T\)

Dimension:

temperature

definition

Z = p * V / (n * R * T)

Latex:

\[Z = \frac{p V}{n R T}\]