1. What is Water Vapor Pressure?

Definition: Water vapor pressure is the pressure exerted by water vapor in thermodynamic equilibrium with its condensed phases at a given temperature.

Purpose: This calculation is essential in meteorology, HVAC design, chemical engineering, and various industrial processes.

2. How Does the Calculator Work?

The calculator uses the Antoine equation:

Where:

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

Explanation: This empirical relationship describes the relationship between temperature and vapor pressure for water.

3. Importance of Water Vapor Pressure Calculation

Details: Accurate vapor pressure calculations are crucial for humidity control, distillation processes, and predicting weather patterns.

4. Using the Calculator

Tips: Enter the temperature in degrees Celsius. The valid range is typically between -100°C and 200°C for this formula.

5. Frequently Asked Questions (FAQ)

Q1: What are the units for vapor pressure?
A: The result is given in mmHg (millimeters of mercury), a common unit for pressure measurements.

Q2: How accurate is this formula?
A: The Antoine equation provides good accuracy for water between 1°C and 100°C, with decreasing accuracy outside this range.

Q3: Can I use this for other liquids?
A: No, this specific formula is only for water. Other substances have different Antoine equation coefficients.

Q4: Why does vapor pressure increase with temperature?
A: As temperature increases, more molecules have sufficient energy to escape the liquid phase, increasing the vapor pressure.

Q5: What's the vapor pressure at boiling point?
A: At 100°C, water's vapor pressure equals atmospheric pressure (760 mmHg at sea level).