How To Calculate Boiling Point Of Water With Atmospheric Pressure

Boiling Point Equation:

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

Atmospheric Pressure (P_atm):

Standard Temperature (T_0):

Standard Pressure (P_0):

Gas Constant (R):

J/mol·K

Enthalpy of Vaporization (ΔH_vap):

J/mol

Boiling Point (T_b):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is the Boiling Point Equation?

The boiling point equation calculates the boiling temperature of water based on atmospheric pressure using the Clausius-Clapeyron relation. It accounts for how pressure affects the temperature at which water transitions from liquid to vapor phase.

2. How Does the Calculator Work?

The calculator uses the boiling point equation:

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

Where:

\( T_b \) — Boiling point (K)
\( T_0 \) — Standard boiling point (373.15 K)
\( R \) — Gas constant (8.314 J/mol·K)
\( \Delta H_{vap} \) — Enthalpy of vaporization (40650 J/mol)
\( P_{atm} \) — Atmospheric pressure (Pa)
\( P_0 \) — Standard pressure (101325 Pa)

Explanation: The equation relates the boiling temperature to atmospheric pressure through thermodynamic principles, showing how boiling point decreases with decreasing pressure.

3. Importance of Boiling Point Calculation

Details: Accurate boiling point calculation is crucial for various applications including cooking at high altitudes, industrial processes, meteorological studies, and scientific experiments where pressure conditions vary.

4. Using the Calculator

Tips: Enter atmospheric pressure in Pascals (Pa), standard values can be kept as defaults or modified for specific conditions. All values must be positive and valid.

5. Frequently Asked Questions (FAQ)

Q1: Why does boiling point change with pressure?
A: Boiling occurs when vapor pressure equals atmospheric pressure. Lower atmospheric pressure means water molecules need less energy to escape, resulting in lower boiling temperature.

Q2: What is the standard boiling point of water?
A: At standard atmospheric pressure (101325 Pa), water boils at 100°C (373.15 K).

Q3: How much does boiling point decrease with altitude?
A: Approximately 1°C for every 300 meters of altitude gain, though the exact value depends on local atmospheric conditions.

Q4: Can this equation be used for other liquids?
A: Yes, but with appropriate values for \( T_0 \), \( P_0 \), and \( \Delta H_{vap} \) specific to each liquid.

Q5: Why use natural logarithm in the equation?
A: The natural logarithm arises from the integration of the Clausius-Clapeyron equation, which describes the relationship between pressure and temperature for phase transitions.