Boiling Point Vapor Pressure Calculator

Boiling Point Equation:

\[ T_b = \frac{1}{\frac{1}{T_0} - \frac{R}{\Delta H_{vap}} \ln \left( \frac{P_{vp}}{P_0} \right)} \]

Reference Temperature (T₀):

Enthalpy of Vaporization (ΔHvap):

J/mol

Vapor Pressure (Pvp):

Standard Pressure (P₀):

Boiling Point (Tb):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is the Boiling Point Equation?

The boiling point equation calculates the boiling temperature of a substance based on its vapor pressure properties. It uses the Clausius-Clapeyron relation to determine how boiling point changes with pressure.

2. How Does the Calculator Work?

The calculator uses the boiling point equation:

\[ T_b = \frac{1}{\frac{1}{T_0} - \frac{R}{\Delta H_{vap}} \ln \left( \frac{P_{vp}}{P_0} \right)} \]

Where:

\( T_b \) — Boiling point (K)
\( T_0 \) — Reference temperature (K)
\( R \) — Gas constant (8.314 J/mol·K)
\( \Delta H_{vap} \) — Enthalpy of vaporization (J/mol)
\( P_{vp} \) — Vapor pressure (Pa)
\( P_0 \) — Standard pressure (Pa)

Explanation: The equation relates the boiling point to vapor pressure through thermodynamic principles, accounting for the energy required for phase change.

3. Importance of Boiling Point Calculation

Details: Accurate boiling point calculation is essential for chemical process design, distillation operations, safety assessments, and understanding substance behavior under different pressure conditions.

4. Using the Calculator

Tips: Enter all values in appropriate units. Reference temperature and boiling point are in Kelvin. Enthalpy in J/mol, pressures in Pascals. All values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: Why use this equation instead of simple boiling point tables?
A: This equation allows calculation of boiling points at various pressures, not just at standard atmospheric pressure.

Q2: What is typical enthalpy of vaporization values?
A: Typical values range from 20-50 kJ/mol for most organic compounds, with water at about 40.7 kJ/mol.

Q3: How accurate is this calculation?
A: The equation provides good estimates for many substances, though accuracy depends on the quality of input parameters.

Q4: Can this be used for mixtures?
A: This equation is primarily for pure substances. Mixtures require more complex calculations due to composition effects.

Q5: What are common reference temperatures?
A: Typically the normal boiling point (at 101325 Pa) is used as reference when calculating boiling points at other pressures.