Water Boiling Point Pressure Calculator Metric

Boiling Point Equation:

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

Boiling Point (T_b):

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1. What is the Boiling Point Equation?

The boiling point equation calculates the temperature at which water boils at a given pressure using thermodynamic principles. It accounts for the relationship between vapor pressure and temperature through the Clausius-Clapeyron equation.

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 (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)
\( P \) — Pressure (kPa)
\( P_0 \) — Standard pressure (101.325 kPa)

Explanation: The equation shows how boiling temperature decreases with decreasing pressure and increases with increasing pressure.

3. Importance of Boiling Point Calculation

Details: Accurate boiling point calculation is crucial for various applications including cooking at high altitudes, industrial processes, scientific research, and understanding atmospheric phenomena.

4. Using the Calculator

Tips: Enter pressure in kilopascals (kPa). The value must be positive. At standard atmospheric pressure (101.325 kPa), water boils at 373.15 K (100°C).

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 water molecules need less energy to escape, so boiling occurs at lower temperatures.

Q2: What is the boiling point at high altitudes?
A: At higher altitudes where pressure is lower, water boils at lower temperatures. For example, at 3000m altitude (~70 kPa), water boils at about 363 K (90°C).

Q3: Can this equation be used for other liquids?
A: The same principle applies, but different liquids have different \( \Delta H_{vap} \) values and standard boiling points.

Q4: How accurate is this calculation?
A: The equation provides good approximations for water under normal conditions, though extreme pressures or temperatures may require more complex models.

Q5: What are practical applications of this calculation?
A: Used in altitude cooking adjustments, pressure cooker design, meteorological studies, and various industrial processes involving evaporation and condensation.