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Total Pressure for Binary Vapour System for Dew-Bubble Point calculations with Modified Raoult's Law Calculator

Total Pressure Formula:

\[ P_T = \frac{1}{\left(\frac{y_1}{\gamma_1 \cdot P_{1}^{sat}} + \frac{y_2}{\gamma_2 \cdot P_{2}^{sat}}\right)} \]

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1. What is Total Pressure for Binary Vapour System?

Definition: This calculator determines the total pressure of a binary vapour system using Modified Raoult's Law, accounting for non-ideal behavior through activity coefficients.

Purpose: It's essential for dew-bubble point calculations in chemical engineering, particularly for vapor-liquid equilibrium (VLE) analysis of non-ideal mixtures.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ P_T = \frac{1}{\left(\frac{y_1}{\gamma_1 \cdot P_{1}^{sat}} + \frac{y_2}{\gamma_2 \cdot P_{2}^{sat}}\right)} \]

Where:

Explanation: The formula accounts for the non-ideal behavior of components through their activity coefficients, modifying Raoult's Law for more accurate calculations.

3. Importance of Total Pressure Calculation

Details: Accurate pressure calculations are crucial for designing separation processes like distillation, predicting phase behavior, and ensuring proper operation of chemical processes.

4. Using the Calculator

Tips: Enter the mole fractions (must sum to 1), activity coefficients (typically >1 for positive deviation from ideality), and saturated pressures. All values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: What are typical values for activity coefficients?
A: For ideal mixtures, γ=1. For non-ideal mixtures, γ can range from 0.1 to 10 or more, depending on the system.

Q2: How do I obtain saturated vapor pressures?
A: Use Antoine equation or vapor pressure tables for pure components at the system temperature.

Q3: What if my mole fractions don't sum to 1?
A: The calculator will still compute, but results may not be physically meaningful. Ensure y₁ + y₂ = 1 for accurate results.

Q4: When is Modified Raoult's Law necessary?
A: When dealing with non-ideal mixtures where molecular interactions cause deviations from ideal behavior.

Q5: Can this be extended to multicomponent systems?
A: Yes, the principle can be extended, but the formula becomes more complex with additional terms for each component.

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