Boiling Point Calculator Vacuum

Boiling Point Under Vacuum Equation:

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

Standard Boiling Point (T₀):

Enthalpy of Vaporization (ΔH_vap):

J/mol

Vacuum Pressure (P):

Standard Pressure (P₀):

Boiling Point Under Vacuum (T_b):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is the Boiling Point Under Vacuum Equation?

The boiling point under vacuum equation calculates the reduced boiling point of a substance when pressure is decreased below atmospheric pressure. This is particularly important in industrial processes where vacuum distillation is used to separate compounds that would decompose at their normal boiling points.

2. How Does the Calculator Work?

The calculator uses the Clausius-Clapeyron 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 under vacuum (K)
\( T_0 \) — Standard boiling point at pressure P₀ (K)
\( R \) — Gas constant (8.314 J/mol·K)
\( \Delta H_{vap} \) — Enthalpy of vaporization (J/mol)
\( P \) — Vacuum pressure (Pa)
\( P_0 \) — Standard pressure (Pa)

Explanation: The equation relates the boiling point temperature to pressure through the enthalpy of vaporization, showing how boiling point decreases as pressure decreases.

3. Importance of Vacuum Boiling Point Calculation

Details: Calculating boiling points under vacuum is crucial for chemical processing, pharmaceutical manufacturing, food processing, and any application where heat-sensitive materials need to be distilled or evaporated without thermal degradation.

4. Using the Calculator

Tips: Enter all values in consistent units (K for temperature, J/mol for enthalpy, Pa for pressure). Ensure standard boiling point and pressure correspond to the same reference conditions (typically 101325 Pa for P₀).

5. Frequently Asked Questions (FAQ)

Q1: Why does boiling point decrease under vacuum?
A: Lower pressure reduces the energy required for molecules to escape the liquid phase, thus lowering the boiling point.

Q2: What is a typical vacuum pressure range?
A: Vacuum pressures typically range from 1000 Pa to 100000 Pa, depending on the application and equipment.

Q3: How accurate is this calculation?
A: The equation assumes constant enthalpy of vaporization and ideal gas behavior, so it's most accurate for moderate pressure reductions.

Q4: Can I use different pressure units?
A: Yes, but all pressure values must be in the same units (convert mmHg, bar, or atm to Pa before calculation).

Q5: What if I get an undefined result?
A: This occurs when the term inside becomes zero, typically when the vacuum pressure is too low relative to the enthalpy and standard conditions.