1. What is a Vapor Pressure Calculator for Water?

Definition: This calculator estimates the vapor pressure of water at a given temperature using the Antoine equation.

Purpose: It helps chemists, engineers, and students determine the pressure exerted by water vapor in equilibrium with its liquid phase at specific temperatures.

2. How Does the Calculator Work?

The calculator uses the Antoine equation:

Where:

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

Explanation: The Antoine equation provides an empirical relationship between vapor pressure and temperature for water.

3. Importance of Vapor Pressure Calculation

Details: Vapor pressure calculations are essential for distillation processes, humidity control, weather forecasting, and chemical process design.

4. Using the Calculator

Tips: Enter the temperature in degrees Celsius. The valid range is typically between -100°C and 300°C for this equation.

5. Frequently Asked Questions (FAQ)

Q1: What is the Antoine equation?
A: An empirical relationship that describes the relationship between vapor pressure and temperature for pure substances.

Q2: Why is vapor pressure important?
A: It determines evaporation rates, boiling points, and is crucial for many industrial and environmental processes.

Q3: What are the limitations of this calculator?
A: The Antoine equation is most accurate for temperatures between 1°C and 100°C, though it provides reasonable estimates over a wider range.

Q4: How does altitude affect vapor pressure?
A: Vapor pressure is temperature-dependent but not directly affected by altitude (though boiling point is).

Q5: Can this be used for salt water or other solutions?
A: No, this calculator is for pure water only. Solutions require different calculations accounting for solute effects.