Redlich–Kwong equation of state calculator V4.2

Calculate pressure/volume/temperature, compressibility factor, and fugacity coefficient for liquid/gas/supercritical fluid.

• Enter the critical temperature and pressure.
• Enter two of three quantities, leaving blank the field to be calculated.
• Select units.
• Click  Calculate  to get the missing quantity, compressibility factor, and fugacity coefficient.

Results:

fluid:	n.a.
gas:	n.a.
liquid:	n.a.

Notation:

• T = temperature
• P = pressure
• Vm = molar volume
• Tc = critical temperature
• Pc = critical pressure
• reduced quantities: Tr=T/Tc, Pr=P/Pc, Vr=Vm/(R*Tc/Pc)
• Z = Pr*Vr/Tr= P*Vm/(R*T) = compressibility factor
• φ = fugacity coefficient
• 1 atm = 101 325 Pa, 1 bar = 100 000 Pa

Notes:

• With T,P given, only the stable phase is calculated.
• With Vm given, metastability/unstability is reported.
• Simple expressions (e.g., 100+273.15) are accepted in input fields.
• Spaces and tabs are ignored on input.
• Both ',' and '.' are accepted as decimal separator on input.

Theory – Theory (in Czech) – Critical data of selected gases (in Czech)

© Jiří Kolafa (2006–2026) by the GNU General Public License 3