Redlich-Kwong (pressure)

The Redlich-Kwong Pressure calculator computes the pressure of a gas using the Redlich-Kwong equation (below).

INSTRUCTION: Enter the following:

• (V)  This is the molar volume
• (T)  This is the temperature
• (a)  This is the attractive potential correction constant
• (b)  This is the volume correction constant

Pressure(P):  The calculator returns the pressure.

The Math / Science

In physics and thermodynamics, the Redlich–Kwong equation of state is an empirical, algebraic equation that relates temperature, pressure, and volume of gases. It is generally more accurate than the van der Waals equation and the ideal gas equation at temperatures above the critical temperature.

The Redlich-Kwong equation is:

                `P = (R*T)/(V-b)  - a/(sqrt(T) * V * (V+b))`

where:

• P is the pressure
• R is the Universal Gas Constant
• V is the molar volume
• T is the temperature
• a is the attractive potential correction constant
• b is the volume correction constant

Furthermore:

        a = 0.42748  (R²•T_c^2.5)/P_c   CLICK HERE

        b = 0.8664 (R•T_c)/P_c          CLICK HERE