1. What is a Vapour Pressure Calculator?

Definition: This calculator estimates the vapour pressure of water based on temperature using the Antoine equation.

Purpose: It helps chemists, engineers, and students determine the pressure exerted by water vapour in equilibrium with its liquid phase at a given temperature.

2. How Does the Calculator Work?

The calculator uses the Antoine equation:

Where:

• \( P \) — Vapour pressure (mmHg)
• \( T \) — Temperature (°C)

Explanation: The equation relates the vapour pressure of water to temperature through empirically derived constants.

3. Importance of Vapour Pressure Calculation

Details: Vapour pressure is crucial for understanding evaporation rates, boiling points, and phase equilibria in chemical processes and atmospheric science.

4. Using the Calculator

Tips: Simply enter the temperature in Celsius. The calculator will compute the vapour pressure in mmHg.

5. Frequently Asked Questions (FAQ)

Q1: What is the Antoine equation?
A: A semi-empirical relationship between vapour pressure and temperature, with constants specific to each substance.

Q2: What's the temperature range for this calculation?
A: This formula is accurate between 1°C and 100°C (water's liquid range at standard pressure).

Q3: Why is vapour pressure important?
A: It affects processes like distillation, drying, and humidity control, and is fundamental in phase equilibrium calculations.

Q4: How does temperature affect vapour pressure?
A: Vapour pressure increases exponentially with temperature - higher temperatures mean more molecules escape the liquid phase.

Q5: What are the units of measurement?
A: Temperature in °C and vapour pressure in mmHg (millimeters of mercury), a common pressure unit in chemistry.