1. What is Van't Hoff Factor?

Definition: The Van't Hoff Factor (i) is the ratio of observed colligative property to theoretical colligative property.

Purpose: It helps quantify the effect of solute particles on colligative properties like vapour pressure lowering.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( i \) — Van't Hoff Factor (unitless)
• \( p_o \) — Vapour pressure of pure solvent (Pa)
• \( p \) — Vapour pressure of solvent in solution (Pa)
• \( m \) — Molality (mol/kg)
• \( M \) — Molecular mass of solvent (kg)

Explanation: The formula relates the relative lowering of vapour pressure to the molality and molecular mass of the solvent.

3. Importance of Van't Hoff Factor

Details: The factor is crucial for understanding solution behavior, especially for electrolytes that dissociate in solution.

4. Using the Calculator

Tips: Enter vapour pressures in pascals, molality in mol/kg, and molecular mass in kg. The default molecular mass (0.018 kg) is for water.

5. Frequently Asked Questions (FAQ)

Q1: What does i = 1 mean?
A: A value of 1 indicates the solute doesn't dissociate or associate in solution (typical for non-electrolytes).

Q2: What's a typical value for NaCl solutions?
A: For NaCl, i approaches 2 (but may be less due to ion pairing at higher concentrations).

Q3: Why is molecular mass in kg?
A: The SI unit for mass is kg, and using consistent units ensures proper calculation.

Q4: What if i > expected value?
A: Values higher than expected may indicate solute association or measurement errors.

Q5: Does temperature affect the result?
A: Temperature affects vapour pressures but not the Van't Hoff factor directly.