1. What is Vapor Pressure of Water?

The vapor pressure of water is the pressure exerted by water vapor in equilibrium with liquid water at a given temperature. It increases with temperature and is important in meteorology, chemistry, and engineering applications.

2. How Does the Calculator Work?

The calculator uses the empirical equation:

Where:

• \( P \) — Vapor pressure in torr
• \( T \) — Temperature in °C
• \( \exp \) — Exponential function

Explanation: This equation approximates the vapor pressure of water over a range of temperatures, with constants derived from experimental data.

3. Importance of Vapor Pressure Calculation

Details: Vapor pressure is crucial for understanding humidity, evaporation rates, boiling points, and is used in weather forecasting, industrial processes, and chemical engineering.

4. Using the Calculator

Tips: Enter temperature in Celsius between -234°C and 1000°C (practical range is typically 0-100°C for water). The result will be in torr (mmHg).

5. Frequently Asked Questions (FAQ)

Q1: What is the unit of vapor pressure?
A: The calculator provides results in torr (equivalent to mmHg), which is the traditional unit for vapor pressure.

Q2: How accurate is this equation?
A: This is an empirical approximation that works well for typical temperatures (0-100°C) but may have increasing error at extremes.

Q3: What's the vapor pressure at boiling point?
A: At 100°C, water's vapor pressure equals atmospheric pressure (760 torr at sea level), causing boiling.

Q4: Why does vapor pressure increase with temperature?
A: Higher temperatures give water molecules more energy to escape the liquid phase, increasing vapor pressure.

Q5: Are there more precise equations available?
A: Yes, the Antoine equation provides more accurate results but requires more complex coefficients.