1. What is the Antoine Equation?

The Antoine equation is a simple 3-parameter fit to experimental vapor pressure data. It relates the vapor pressure of a substance to its temperature and is widely used in chemical engineering and thermodynamics.

2. How Does the Calculator Work?

The calculator uses the Antoine equation:

Where:

• \( P \) — Vapor pressure (mmHg)
• \( A \) — Substance-specific constant (dimensionless)
• \( B \) — Substance-specific constant (dimensionless)
• \( C \) — Substance-specific constant (dimensionless)
• \( T \) — Temperature (°C)

Explanation: The equation provides a semi-empirical relationship between vapor pressure and temperature for many substances.

3. Importance of Vapor Pressure Calculation

Details: Vapor pressure is crucial for designing distillation columns, predicting evaporation rates, understanding phase equilibria, and assessing chemical safety.

4. Using the Calculator

Tips: Enter the substance-specific Antoine constants (A, B, C) and the temperature in °C. The calculator will compute the vapor pressure in mmHg.

5. Frequently Asked Questions (FAQ)

Q1: Where can I find Antoine constants for different substances?
A: Antoine constants are available in chemical engineering handbooks, thermodynamic databases, and scientific literature.

Q2: What is the temperature range for the Antoine equation?
A: The equation is typically valid over a limited temperature range (usually the normal boiling point ±50°C).

Q3: Why does the equation use base-10 logarithm?
A: The base-10 form is conventional for the Antoine equation, though mathematically equivalent to natural logarithm forms.

Q4: Are there limitations to this equation?
A: The equation may not be accurate near critical points or for associating substances. Extended forms exist for wider ranges.

Q5: Can this be used for mixtures?
A: For mixtures, Raoult's law or other mixing rules must be applied to the pure component vapor pressures.