1. What is the Boiling Point Equation?

The boiling point equation estimates how the boiling point of a liquid changes with pressure. It's derived from the Clausius-Clapeyron relation and is useful in chemistry and engineering applications.

2. How Does the Calculator Work?

The calculator uses the boiling point equation:

Where:

• \( T \) — Boiling point at pressure P (K)
• \( T_0 \) — Normal boiling point (K)
• \( \Delta H_{vap} \) — Heat of vaporization (J/mol)
• \( R \) — Universal gas constant (8.314 J/mol·K)
• \( P \) — Desired pressure (atm)
• \( P_0 \) — Reference pressure (typically 1 atm)

Explanation: The equation shows that boiling point decreases with decreasing pressure and increases with increasing pressure.

3. Importance of Boiling Point Calculation

Details: Understanding how boiling point changes with pressure is crucial for distillation processes, high-altitude cooking, vacuum evaporation, and chemical process design.

4. Using the Calculator

Tips: Enter all values in the specified units. The reference pressure (P₀) is typically 1 atm (standard atmospheric pressure). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: Why does boiling point change with pressure?
A: Boiling occurs when vapor pressure equals external pressure. Lower external pressure means less energy (lower temperature) is needed for boiling.

Q2: How accurate is this calculation?
A: It's reasonably accurate for small pressure changes. For large ranges or precise work, more complex equations may be needed.

Q3: Can I use mmHg instead of atm?
A: Yes, as long as both P and P₀ use the same units. 1 atm = 760 mmHg.

Q4: What's a typical heat of vaporization value?
A: For water it's about 40,700 J/mol. Values vary significantly between substances.

Q5: How does altitude affect boiling point?
A: Higher altitude means lower atmospheric pressure, resulting in lower boiling points (about 1°C drop per 300m elevation for water).