Enthalpy Of Vaporization Calculator

Clausius-Clapeyron Equation:

\[ \Delta H_v = R \times \frac{T_1 \times T_2}{T_2 - T_1} \times \ln\left(\frac{P_2}{P_1}\right) \]

Gas Constant (R):

J/mol·K

Temperature 1 (T₁):

Temperature 2 (T₂):

Pressure 1 (P₁):

Pressure 2 (P₂):

Enthalpy Of Vaporization (ΔH_v):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is the Clausius-Clapeyron Equation?

The Clausius-Clapeyron equation relates the vapor pressure of a substance to its temperature and enthalpy of vaporization. It provides a way to calculate the heat required to vaporize a mole of liquid at a given temperature.

2. How Does the Calculator Work?

The calculator uses the Clausius-Clapeyron equation:

\[ \Delta H_v = R \times \frac{T_1 \times T_2}{T_2 - T_1} \times \ln\left(\frac{P_2}{P_1}\right) \]

Where:

\( \Delta H_v \) — Enthalpy of vaporization (J/mol)
\( R \) — Gas constant (8.314 J/mol·K)
\( T_1, T_2 \) — Temperatures at two different points (K)
\( P_1, P_2 \) — Vapor pressures at temperatures T₁ and T₂ (Pa)

Explanation: The equation calculates the energy required to convert one mole of liquid into vapor at a specific temperature, based on vapor pressure measurements at two different temperatures.

3. Importance of Enthalpy of Vaporization Calculation

Details: Enthalpy of vaporization is crucial for understanding phase transitions, designing distillation processes, and studying thermodynamic properties of substances. It's particularly important in chemical engineering and physical chemistry applications.

4. Using the Calculator

Tips: Enter the gas constant (typically 8.314 J/mol·K), two temperatures in Kelvin, and the corresponding vapor pressures in Pascals. Ensure T₂ ≠ T₁ to avoid division by zero.

5. Frequently Asked Questions (FAQ)

Q1: What is the typical range of enthalpy of vaporization values?
A: Enthalpy of vaporization values typically range from 8-50 kJ/mol for common liquids, with water having a value of about 40.7 kJ/mol at 100°C.

Q2: Why must temperatures be in Kelvin?
A: The gas constant R is defined in J/mol·K, and the equation requires absolute temperature for thermodynamic consistency.

Q3: What are the limitations of the Clausius-Clapeyron equation?
A: The equation assumes ideal gas behavior and constant enthalpy of vaporization over the temperature range, which may not hold for large temperature differences.

Q4: Can this calculator be used for any substance?
A: Yes, as long as you have accurate vapor pressure data at two different temperatures for the substance.

Q5: How accurate is this calculation?
A: The accuracy depends on the precision of the input data. For small temperature differences and substances that follow ideal behavior, the results are quite accurate.