1. What is Vapour Phase Mole Fraction using Raoult's Law?

Definition: This calculator determines the mole fraction of a component in the vapour phase based on Raoult's Law in vapor-liquid equilibrium (VLE) systems.

Purpose: It helps chemical engineers and chemists predict the composition of vapour in equilibrium with a liquid mixture.

2. How Does the Calculator Work?

The calculator uses Raoult's Law formula:

Where:

• \( y_{Gas} \) — Mole fraction in vapour phase
• \( x_{Liquid} \) — Mole fraction in liquid phase (0 to 1)
• \( P^{sat} \) — Saturated vapor pressure (Pa)
• \( P_T \) — Total system pressure (Pa)

Explanation: The liquid phase mole fraction is multiplied by the saturated pressure and divided by total pressure to get the vapour phase composition.

3. Importance of Vapour Phase Mole Fraction

Details: Accurate prediction of vapour composition is crucial for distillation column design, phase equilibrium studies, and chemical process simulations.

4. Using the Calculator

Tips: Enter the liquid phase mole fraction (0-1), saturated pressure (Pa), and total pressure (Pa). All pressure values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is Raoult's Law?
A: Raoult's Law states that the partial pressure of a component in vapour phase is equal to the product of its mole fraction in liquid phase and its pure component vapor pressure.

Q2: When is Raoult's Law applicable?
A: It applies to ideal mixtures where intermolecular forces between different molecules are similar to those between like molecules.

Q3: What if my system is non-ideal?
A: For non-ideal systems, activity coefficients should be included in the calculation (modified Raoult's Law).

Q4: How do I find saturated pressure values?
A: Saturated pressure can be found in chemical engineering handbooks or calculated using Antoine equation for pure components.

Q5: What units should I use for pressure?
A: The calculator uses Pascals (Pa), but any consistent pressure units can be used as long as both pressures are in the same units.