Boiling Point Vs Pressure Calculator

Boiling Point Vs Pressure Formula:

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

Reference Temperature (T₀):

Enthalpy of Vaporization (ΔH_vap):

J/mol

Pressure (P):

Reference Pressure (P₀):

Boiling Point (T_b):

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1. What is the Boiling Point Vs Pressure Equation?

The boiling point vs pressure equation calculates how the boiling point of a substance changes with pressure. It's based on the Clausius-Clapeyron relation and provides a mathematical relationship between boiling temperature and pressure.

2. How Does the Calculator Work?

The calculator uses the boiling point vs pressure 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 (K)
\( T_0 \) — Reference temperature (K)
\( R \) — Gas constant (8.314 J/mol·K)
\( \Delta H_{vap} \) — Enthalpy of vaporization (J/mol)
\( P \) — Pressure (Pa)
\( P_0 \) — Reference pressure (Pa)

Explanation: The equation shows how boiling temperature increases with pressure and depends on the substance's enthalpy of vaporization.

3. Importance of Boiling Point Calculation

Details: Understanding how boiling point changes with pressure is crucial for various industrial processes, high-altitude cooking, chemical engineering, and laboratory work where pressure conditions vary.

4. Using the Calculator

Tips: Enter reference temperature in Kelvin, enthalpy of vaporization in J/mol, pressure in Pascal, and reference pressure in Pascal. All values must be positive and non-zero.

5. Frequently Asked Questions (FAQ)

Q1: Why does boiling point change with pressure?
A: Boiling occurs when vapor pressure equals atmospheric pressure. At higher pressures, more energy (higher temperature) is needed for vapor pressure to reach the surrounding pressure.

Q2: What are typical values for enthalpy of vaporization?
A: Water has ΔH_vap ≈ 40.65 kJ/mol at 100°C. Different substances have different values, typically ranging from 20-50 kJ/mol.

Q3: How accurate is this equation?
A: The equation provides good estimates for moderate pressure changes but may have limitations for extreme pressures or near critical points.

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

Q5: Why use Pascal as pressure unit?
A: Pascal is the SI unit for pressure. For convenience, you can convert from other units (1 atm = 101325 Pa, 1 bar = 100000 Pa).