1. What is Relative Lowering of Vapour Pressure?

Definition: The Relative Lowering of Vapour Pressure is the lowering of vapour pressure of pure solvent on addition of solute.

Purpose: It helps in understanding colligative properties of solutions and is important in physical chemistry studies.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( \Delta p \) — Relative Lowering of Vapour Pressure
• \( m \) — Molality (mol/kg)
• \( M \) — Molecular Mass of Solvent (kg)

Explanation: The molality is multiplied by the molecular mass of the solvent and divided by 1000 to get the relative lowering of vapour pressure.

3. Importance of Relative Lowering of Vapour Pressure

Details: This measurement is crucial for understanding solution behavior, determining molecular weights, and studying colligative properties.

4. Using the Calculator

Tips: Enter the molality in mol/kg and molecular mass of solvent in kg (default 0.018 kg for water). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is the typical molecular mass for water?
A: The molecular mass of water is typically 0.018 kg (18 g/mol).

Q2: How does molality differ from molarity?
A: Molality is moles of solute per kg of solvent, while molarity is moles per liter of solution.

Q3: Why is this considered a colligative property?
A: It depends on the number of solute particles rather than their nature.

Q4: What are practical applications of this calculation?
A: Used in determining molecular weights, studying solution properties, and in industrial processes.

Q5: How does temperature affect this calculation?
A: While the formula doesn't explicitly include temperature, vapour pressure itself is temperature-dependent.