1. What is the Evaporation Rate Equation?

The evaporation rate equation estimates the mass transfer rate of a liquid evaporating into a gas. It's based on the difference between saturation pressure and vapor pressure, surface area, and temperature.

2. How Does the Calculator Work?

The calculator uses the evaporation rate equation:

Where:

• \( E \) — Evaporation rate (kg/s)
• \( P_{sat} \) — Saturation pressure (Pa)
• \( P_v \) — Vapor pressure (Pa)
• \( A \) — Surface area (m²)
• \( R \) — Gas constant (8.314 J/mol·K)
• \( T \) — Temperature (K)

Explanation: The equation shows that evaporation rate increases with greater pressure difference and surface area, and decreases with higher temperature.

3. Importance of Evaporation Rate Calculation

Details: Calculating evaporation rate is crucial for chemical engineering processes, environmental studies, and industrial applications where precise control of evaporation is needed.

4. Using the Calculator

Tips: Enter all values in SI units. Ensure temperature is in Kelvin (K = °C + 273.15). The gas constant is pre-set to 8.314 J/mol·K but can be adjusted if needed.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between P_sat and P_v?
A: P_sat is the maximum vapor pressure at a given temperature, while P_v is the actual vapor pressure in the system.

Q2: Why does temperature appear in the denominator?
A: Higher temperature means more energy per molecule, so fewer molecules are needed to achieve the same pressure.

Q3: What are typical evaporation rates?
A: Rates vary widely but are often in the range of 10^-6 to 10^-3 kg/s for many industrial applications.

Q4: Are there limitations to this equation?
A: This assumes ideal gas behavior and doesn't account for convection or other mass transfer mechanisms.

Q5: How does surface area affect evaporation?
A: Evaporation rate is directly proportional to surface area - doubling the area doubles the evaporation rate.