Real Gas Equation Calculator

Calculate Real Gas Properties

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Van der Waals Equation Calculator

Calculate pressure using the van der Waals equation of state.

Pressure: - atm

Redlich-Kwong Equation Calculator

Calculate pressure using the Redlich-Kwong equation of state.

Pressure: - atm

Real Gas Parameters Calculator

Calculate van der Waals parameters from critical properties.

Parameter a: - L²⋅atm/mol²
Parameter b: - L/mol

Understanding Real Gas Equations

Real Gas Behavior

Real gases deviate from ideal behavior due to:

  • Molecular volume effects
  • Intermolecular forces
  • High pressure conditions
  • Low temperature conditions

Van der Waals Equation

The van der Waals equation accounts for:

  • Molecular volume (parameter b)
  • Intermolecular attractions (parameter a)
  • Pressure correction term
  • Volume correction term

Redlich-Kwong Equation

Improvements over van der Waals:

  • Better temperature dependence
  • More accurate at high pressures
  • Modified attraction term
  • Better critical point prediction

Critical Properties

At the critical point:

  • Liquid and gas phases become indistinguishable
  • Used to determine equation parameters
  • Define reduced properties
  • Important for corresponding states

Essential Real Gas Formulas

Van der Waals Equation

(P + an²/V²)(V - nb) = nRT

Where a and b are van der Waals parameters

Redlich-Kwong Equation

P = RT/(V-b) - a/(T^0.5V(V+b))

Modified attraction term with temperature dependence

Van der Waals Parameters

a = 27R²Tc²/(64Pc)

b = RTc/(8Pc)