Activity Coefficient Calculator

Calculate Solution Non-Ideality

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Margules Equation Calculator

Calculate activity coefficients using the Margules equation for binary mixtures.

γ₁: -
γ₂: -

Wilson Equation Calculator

Calculate activity coefficients using the Wilson equation.

γ₁: -
γ₂: -

Excess Properties Calculator

Calculate excess Gibbs energy and other excess properties.

Excess Gibbs Energy: - J/mol

Understanding Activity Coefficients

What are Activity Coefficients?

Activity coefficients measure solution non-ideality:

  • Correction factor for Raoult's law
  • Measure of molecular interactions
  • Temperature and composition dependent
  • Unity for ideal solutions

Margules Equation

The Margules model is useful for:

  • Binary mixtures
  • Similar sized molecules
  • Moderate non-ideality
  • Simple parameter estimation

Wilson Equation

Advantages of Wilson equation:

  • Better for polar/associating compounds
  • Temperature dependence included
  • Based on local composition concept
  • Good for miscible systems

Applications

Activity coefficients are important for:

  • Vapor-liquid equilibrium
  • Liquid-liquid extraction
  • Chemical equilibrium
  • Process design
  • Azeotrope prediction

Essential Activity Coefficient Formulas

Margules Equation

ln γ₁ = x₂²[A₁₂ + 2(A₂₁-A₁₂)x₁]

ln γ₂ = x₁²[A₂₁ + 2(A₁₂-A₂₁)x₂]

Wilson Equation

ln γ₁ = -ln(x₁ + Λ₁₂x₂) + x₂(Λ₁₂/(x₁ + Λ₁₂x₂) - Λ₂₁/(Λ₂₁x₁ + x₂))

Excess Gibbs Energy

gᴱ = RT(x₁ln γ₁ + x₂ln γ₂)