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: This calculation helps understand how adding a solute affects the solvent's properties, important in colligative properties studies.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( RLVP \) — Relative Lowering of Vapour Pressure
• \( ΔH_{fusion} \) — Molar Enthalpy of Fusion (J/mol)
• \( ΔT_f \) — Depression in Freezing Point (K)
• \( [R] \) — Universal gas constant (8.314 J/mol·K)
• \( T_{fp} \) — Solvent Freezing Point (K)

Explanation: The formula relates the freezing point depression to the relative lowering of vapour pressure through thermodynamic principles.

3. Importance of This Calculation

Details: Understanding this relationship helps in predicting solution behavior, designing antifreeze solutions, and studying colligative properties.

4. Using the Calculator

Tips: Enter the molar enthalpy of fusion, freezing point depression, and solvent freezing point. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is typical value for molar enthalpy of fusion?
A: For water it's 333.5 kJ/mol, but varies by substance. Check thermodynamic tables for specific materials.

Q2: Why is the freezing point in Kelvin?
A: The formula requires absolute temperature. Remember 0°C = 273.15K.

Q3: What does a higher RLVP value indicate?
A: A higher value indicates greater lowering of vapour pressure relative to the pure solvent.

Q4: Can this be used for any solvent?
A: Yes, as long as you have the correct parameters for your specific solvent.

Q5: How accurate is this calculation?
A: It provides theoretical values for ideal solutions. Real solutions may show deviations.