Excess Gibbs Free Energy Formula:
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Definition: This calculator computes the excess Gibbs free energy for a binary liquid mixture using the Van Laar equation.
Purpose: It helps chemical engineers and researchers understand the non-ideal behavior of liquid mixtures.
The calculator uses the Van Laar equation:
Where:
Explanation: The equation accounts for the non-ideal interactions between different molecules in a binary mixture.
Details: Excess Gibbs free energy helps predict phase equilibria, activity coefficients, and vapor-liquid equilibrium behavior in non-ideal mixtures.
Tips: Enter temperature in Kelvin, mole fractions (sum ≤ 1), and Van Laar coefficients. All values must be valid (temperature > 0, mole fractions between 0 and 1).
Q1: What are typical values for Van Laar coefficients?
A: They vary by system but typically range between 0.1 and 3.0 for many common binary mixtures.
Q2: How do I obtain Van Laar coefficients?
A: They are usually determined experimentally from vapor-liquid equilibrium data or estimated from group contribution methods.
Q3: Can this be used for multicomponent systems?
A: No, the Van Laar equation is strictly for binary systems. Extensions exist for multicomponent systems.
Q4: What's the relationship between G^E and activity coefficients?
A: The activity coefficients can be derived from the partial derivatives of G^E with respect to composition.
Q5: When is the Van Laar equation most accurate?
A: It works well for moderately non-ideal systems but may not be accurate for highly non-ideal or associating mixtures.