1. What is Saturation Vapor Pressure?

Definition: The Saturation Vapor Pressure is defined as the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases (solid or liquid) at a given temperature in a closed system.

Purpose: This calculator helps determine the maximum water vapor pressure that can exist at a given temperature before condensation occurs.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( e_s \) — Saturation vapor pressure (Pascals)
• \( \frac{de}{dT} \) — Slope of the coexistence curve (Pa/K)
• \( R \) — Universal gas constant (8.314 J/mol·K)
• \( T \) — Temperature (Kelvin)
• \( L \) — Specific latent heat (J/kg)

Explanation: The formula relates the temperature dependence of vapor pressure to the latent heat of vaporization.

3. Importance of Saturation Vapor Pressure

Details: Understanding saturation vapor pressure is crucial for meteorology, HVAC systems, industrial processes, and any application involving phase changes of water.

4. Using the Calculator

Tips: Enter the slope of the coexistence curve (default 25 Pa/K), temperature (default 85 K), and specific latent heat (default 208505.9 J/kg). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is the slope of the coexistence curve?
A: It's the rate of change of vapor pressure with temperature at equilibrium between phases.

Q2: What are typical values for specific latent heat?
A: For water at 0°C, it's about 2.5×10⁶ J/kg for vaporization and 3.34×10⁵ J/kg for fusion.

Q3: Why is temperature in Kelvin?
A: Kelvin is the absolute temperature scale required for thermodynamic calculations.

Q4: How does pressure affect the results?
A: This calculation assumes standard pressure conditions (near 1 atm).

Q5: What's the practical application of this calculation?
A: It's used in weather forecasting, cloud formation studies, and designing humidity control systems.