1. What is Activity Coefficient in Modified Raoult's Law?

Definition: The activity coefficient is a factor used in thermodynamics to account for deviations from ideal behavior in a mixture of chemical substances.

Purpose: It helps chemical engineers and researchers accurately predict vapor-liquid equilibrium in non-ideal systems.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( \gamma_{Raoults} \) — Activity coefficient (dimensionless)
• \( K \) — K-value (ratio of vapor-phase to liquid-phase mole fraction)
• \( P_T \) — Total system pressure (Pascals)
• \( P_{Saturated} \) — Saturation pressure of the component (Pascals)

Explanation: The K-value is multiplied by total pressure and divided by the component's saturation pressure to determine its activity coefficient.

3. Importance of Activity Coefficient Calculation

Details: Accurate activity coefficients are crucial for designing distillation columns, predicting phase behavior, and modeling chemical processes.

4. Using the Calculator

Tips: Enter the K-value (typically between 0 and 1), total system pressure in Pascals, and component saturation pressure in Pascals. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What does the activity coefficient tell us?
A: It indicates how much a component deviates from ideal behavior in a mixture (γ=1 for ideal, γ>1 for positive deviation, γ<1 for negative deviation).

Q2: How is K-value determined?
A: K-value is typically measured experimentally or calculated from vapor-liquid equilibrium data.

Q3: What's a typical range for activity coefficients?
A: While theoretically unlimited, most practical systems have γ between 0.1 and 10.

Q4: When would I need this calculation?
A: When working with non-ideal mixtures in distillation, absorption, or other separation processes.

Q5: How does temperature affect the result?
A: Temperature primarily affects the saturation pressure value in the denominator of the equation.