1. What is K-Value in Modified Raoult's Law?

Definition: The K-value is defined as the ratio of vapor-phase mole fraction to the liquid-phase mole fraction of a component in a mixture.

Purpose: It's crucial in vapor-liquid equilibrium calculations for designing and analyzing distillation columns and other separation processes.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( K \) — K-value (dimensionless)
• \( \gamma_{Raoults} \) — Activity coefficient in Raoult's Law
• \( P_{Saturated} \) — Saturated pressure of the component (Pascal)
• \( P_T \) — Total pressure of the gas (Pascal)

Explanation: The activity coefficient accounts for non-ideal behavior, while the ratio of pressures determines the equilibrium distribution.

3. Importance of K-Value Calculation

Details: Accurate K-values are essential for designing efficient separation processes, predicting phase behavior, and optimizing chemical processes.

4. Using the Calculator

Tips: Enter the activity coefficient (typically between 0 and 10), saturated pressure in Pascals, and total system pressure in Pascals. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical range for K-values?
A: K-values typically range from 0.001 to 1000, depending on the component and system conditions.

Q2: When is the activity coefficient equal to 1?
A: The activity coefficient is 1 for ideal solutions where components behave similarly to their pure states.

Q3: How does temperature affect K-values?
A: Temperature primarily affects the saturated pressure term - higher temperatures generally increase K-values.

Q4: What's the difference between Raoult's Law and Modified Raoult's Law?
A: Modified Raoult's Law includes the activity coefficient to account for non-ideal behavior, while standard Raoult's Law assumes ideal behavior.

Q5: How do I find activity coefficients?
A: Activity coefficients can be determined experimentally or calculated using thermodynamic models like UNIFAC or NRTL.