Boiling Point At Different Pressure Calculator

Boiling Point Equation:

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

Reference Temperature (T₀):

Enthalpy of Vaporization (ΔHvap):

J/mol

Pressure (P):

Reference Pressure (P₀):

Boiling Point (Tb):

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1. What is the Boiling Point Equation?

The boiling point equation calculates the boiling temperature of a substance at different pressures using the Clausius-Clapeyron relation. It accounts for how pressure affects the boiling point of liquids.

2. How Does the Calculator Work?

The calculator uses the boiling point equation:

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

Where:

\( T_b \) — Boiling point at pressure P (K)
\( T_0 \) — Reference boiling point at pressure P₀ (K)
\( R \) — Gas constant (8.314 J/mol·K)
\( \Delta H_{vap} \) — Enthalpy of vaporization (J/mol)
\( P \) — Pressure at which boiling point is calculated (Pa)
\( P_0 \) — Reference pressure (Pa)

Explanation: The equation shows how boiling point changes with pressure based on the thermodynamic properties of the substance.

3. Importance of Boiling Point Calculation

Details: Accurate boiling point calculation is crucial for chemical engineering processes, distillation systems, high-altitude cooking, and understanding phase behavior of substances under different pressure conditions.

4. Using the Calculator

Tips: Enter all values in appropriate units (K for temperature, J/mol for enthalpy, Pa for pressure). Ensure all values are positive and reference conditions are known.

5. Frequently Asked Questions (FAQ)

Q1: Why does boiling point change with pressure?
A: Boiling occurs when vapor pressure equals atmospheric pressure. Lower pressure means less energy is needed for vaporization, lowering the boiling point.

Q2: What are typical enthalpy of vaporization values?
A: Water has ΔHvap ≈ 40.65 kJ/mol at 100°C. Values vary by substance and temperature, typically ranging from 20-50 kJ/mol for common liquids.

Q3: How accurate is this equation?
A: The equation assumes constant enthalpy of vaporization, which is reasonable for small pressure changes but may have errors for large pressure differences.

Q4: Can this be used for any liquid?
A: Yes, but accurate results require correct enthalpy of vaporization values specific to the substance and temperature range.

Q5: What's the practical application of this calculation?
A: Used in chemical plant design, vacuum distillation, aerospace applications, and understanding cooking at high altitudes.