1. What is Vapour Phase Mole Fraction using Gamma-Phi Formulation?

Definition: This calculator determines the mole fraction of a component in the vapour phase using the Gamma-Phi formulation of Vapor-Liquid Equilibrium (VLE).

Purpose: It's essential for chemical engineers and chemists working with phase equilibria in distillation, evaporation, and other separation processes.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( y_{Gas} \) — Mole fraction in vapour phase
• \( x_{Liquid} \) — Mole fraction in liquid phase (0 to 1)
• \( \gamma \) — Activity coefficient (≥ 1)
• \( P^{sat} \) — Saturated pressure (Pa)
• \( \phi \) — Fugacity coefficient (typically close to 1)
• \( P_T \) — Total system pressure (Pa)

Explanation: The formula accounts for non-ideal behavior in both liquid (γ) and vapour (φ) phases.

3. Importance of Gamma-Phi Formulation

Details: This approach is crucial for accurate VLE calculations in real systems where ideal behavior assumptions fail.

4. Using the Calculator

Tips:

• Enter liquid mole fraction (0-1)
• Default γ = 1 for ideal solutions
• Default φ = 1 for ideal gas behavior
• All pressure values must be in Pascals (Pa)

5. Frequently Asked Questions (FAQ)

Q1: When should I use values other than 1 for γ?
A: Use γ > 1 for non-ideal liquid mixtures where components interact differently than in ideal solutions.

Q2: What affects the fugacity coefficient φ?
A: φ deviates from 1 under high pressures or when molecular interactions are significant in the vapour phase.

Q3: How do I obtain P^sat values?
A: Use Antoine equation or vapor pressure tables for pure components at the system temperature.

Q4: Can y_Gas exceed 1?
A: No, if your result is >1, check your input values - this indicates impossible conditions.

Q5: What's the difference between Gamma-Phi and Raoult's Law?
A: Raoult's Law assumes ideal behavior (γ=1, φ=1), while Gamma-Phi accounts for real system deviations.