1. What is the Ratio of Partial Vapour Pressures?

Definition: This calculator determines the ratio of partial vapour pressures of two immiscible liquids based on their weights and molecular masses.

Purpose: It helps chemists and chemical engineers understand the relative volatility of immiscible liquid mixtures.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( P_{A:B} \) — Ratio of partial pressures of liquid A to liquid B
• \( W_A \) — Weight of liquid A (kg)
• \( M_A \) — Molecular mass of liquid A (kg/mol)
• \( W_B \) — Weight of liquid B (kg)
• \( M_B \) — Molecular mass of liquid B (kg/mol)

Explanation: The ratio of vapour pressures is directly proportional to the ratio of the products of weights and molecular masses of the opposite components.

3. Importance of Pressure Ratio Calculation

Details: Understanding this ratio is crucial for distillation processes, predicting boiling points of mixtures, and designing separation systems.

4. Using the Calculator

Tips: Enter the weights and molecular masses of both liquids. All values must be > 0. The calculator provides the pressure ratio with high precision (6 decimal places).

5. Frequently Asked Questions (FAQ)

Q1: What are immiscible liquids?
A: Immiscible liquids are those that don't mix to form a homogeneous solution (like oil and water).

Q2: Why does the molecular mass affect vapour pressure?
A: Heavier molecules generally have lower vapour pressures as they require more energy to escape the liquid phase.

Q3: Can this be used for miscible liquids?
A: No, this formula specifically applies to immiscible liquid mixtures.

Q4: What does a ratio > 1 indicate?
A: It means liquid A has a higher partial vapour pressure than liquid B in the mixture.

Q5: How is this related to Raoult's Law?
A: This is a special case for immiscible liquids, where each liquid contributes independently to the total vapour pressure.