1. What is a Temperature to Vapor Pressure Calculator?

Definition: This calculator estimates the vapor pressure of a substance based on temperature using the Clausius-Clapeyron relation.

Purpose: It helps scientists, engineers, and students determine the vapor pressure at different temperatures for various applications.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( P \) — Vapor pressure (Pa)
• \( P_0 \) — Reference pressure (Pa)
• \( L \) — Latent heat of vaporization (J/kg)
• \( R \) — Gas constant (461.5 J/kg·K for water vapor)
• \( T \) — Temperature (Kelvin)

Explanation: The formula shows how vapor pressure changes exponentially with temperature.

3. Importance of Vapor Pressure Calculation

Details: Vapor pressure calculations are crucial for weather forecasting, chemical engineering processes, and understanding phase transitions.

4. Using the Calculator

Tips: Enter the reference pressure (default 611.657 Pa for water at 0°C), latent heat (default 2.5×10⁶ J/kg for water), and temperature in Kelvin. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is the reference pressure P₀?
A: This is the vapor pressure at a known reference temperature, typically the triple point or normal boiling point.

Q2: How accurate is this calculation?
A: It provides a good approximation, but for precise work, more complex equations like Antoine equation may be needed.

Q3: Can I use this for substances other than water?
A: Yes, but you'll need to input the correct P₀, L, and R values for that specific substance.

Q4: Why use Kelvin for temperature?
A: Kelvin is an absolute temperature scale required for thermodynamic calculations.

Q5: What's the typical range for vapor pressure?
A: Vapor pressure varies widely, from near 0 Pa at low temperatures to 101325 Pa (1 atm) at boiling point.