1. What is Enthalpy of Vaporization using Trouton's Rule?

Definition: This calculator estimates the enthalpy of vaporization (ΔH_vap) based on Trouton's rule, which relates the boiling point of a liquid to its enthalpy of vaporization.

Purpose: It provides a quick estimation of the energy required to vaporize one mole of a liquid at its boiling point.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( H \) — Enthalpy of vaporization (Joules)
• \( bp \) — Boiling point (Kelvin)
• \( [R] \) — Universal gas constant (8.314 J/mol·K)
• 10.5 — Trouton's constant (dimensionless)

Explanation: Trouton's rule states that the entropy of vaporization is approximately constant for many liquids (about 10.5R).

3. Importance of Enthalpy Calculation

Details: The enthalpy of vaporization is crucial for designing distillation systems, understanding phase transitions, and calculating thermodynamic properties.

4. Using the Calculator

Tips: Enter the boiling point in Kelvin. The boiling point must be > 0. The calculator uses the standard Trouton's constant of 10.5 and universal gas constant.

5. Frequently Asked Questions (FAQ)

Q1: What is Trouton's rule?
A: It's an empirical rule stating that the entropy of vaporization is approximately constant (ΔS_vap ≈ 10.5R) for many liquids at their boiling points.

Q2: How accurate is this estimation?
A: It provides reasonable estimates (within 10-20%) for non-polar liquids that don't form hydrogen bonds.

Q3: When does Trouton's rule not apply?
A: For polar liquids, especially those forming hydrogen bonds (like water), or very low boiling point liquids.

Q4: Why is the result in Joules?
A: The calculation gives the enthalpy per mole. Multiply by the number of moles for total energy.

Q5: Can I use Celsius instead of Kelvin?
A: No, the calculation requires absolute temperature (Kelvin). Convert Celsius to Kelvin by adding 273.15.