Compressibility factor is deviation from ideal gas

The compressibility factor, also known as the compression factor or the gas deviation factor, describes the deviation of a real gas from ideal gas behavior. In general, the deviation from ideal gas behavior becomes more prominent the closer the gas is to a phase change, the lower the temperature or the larger the pressure.

Notation:

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

Notes:

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

2. \(Z = 1\) is the case of ideal gas behavior.

3. At high pressures molecules collide more often leading to an increase of repulsive forces between molecules, making the molar volume of the real gas greater than that of ideal gas, in other words the particles have a larger extended volume, leading to \(Z > 1\).

4. At lower pressures, molecules are free to move and attractive forces dominate, leading to \(Z < 1\).

Links:

1. Wikipedia, second formula.

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 gas.

Symbol:

n

Latex:

\(n\)

Dimension:

amount_of_substance

temperature

Gas temperature.

Symbol:

T

Latex:

\(T\)

Dimension:

temperature

definition

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

Latex:

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