Excess Gibbs Free Energy Formula:
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Definition: Excess Gibbs Free Energy (Gᴱ) is the difference between the actual Gibbs free energy of a solution and what it would have if it were an ideal solution.
Purpose: It quantifies the non-ideality of liquid mixtures and is crucial for understanding phase equilibria in chemical engineering.
The calculator uses the Margules two-parameter equation:
Where:
Explanation: The equation accounts for interactions between different molecules in a binary mixture.
Details: Gᴱ helps predict vapor-liquid equilibria, activity coefficients, and phase behavior in non-ideal mixtures.
Tips: Enter temperature in Kelvin, mole fractions (must sum to ≤1), and Margules coefficients. All values must be valid.
Q1: What are typical values for Margules coefficients?
A: They vary by system but typically range from -1 to 2 for moderately non-ideal mixtures.
Q2: How do I obtain Margules coefficients?
A: They are determined experimentally from vapor-liquid equilibrium data or activity coefficient measurements.
Q3: Can this be used for ternary systems?
A: No, this calculator is specifically for binary systems. Ternary systems require additional parameters.
Q4: What's the relationship between Gᴱ and activity coefficients?
A: The activity coefficients can be derived from the partial derivatives of Gᴱ with respect to composition.
Q5: Why is temperature important in this calculation?
A: Temperature affects molecular interactions and thus the degree of non-ideality in the mixture.