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Antoine Equation:
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Definition: The Antoine equation is a semi-empirical relationship that describes the relationship between vapor pressure and temperature for pure substances.
Purpose: It's widely used in chemical engineering and thermodynamics to estimate the vapor pressure of liquids at various temperatures.
The equation is expressed as:
Where:
Explanation: The equation relates the logarithm of vapor pressure to the reciprocal of temperature, with constants that are empirically determined for each substance.
Details: Vapor pressure is crucial for designing distillation columns, predicting evaporation rates, understanding phase equilibria, and assessing chemical storage safety.
Tips: Enter the temperature in °C and the Antoine constants (A, B, C) for your specific substance. Default values are for water (0-60°C range).
Q1: Where can I find Antoine constants for different substances?
A: Chemical engineering handbooks, NIST databases, or scientific literature typically provide these constants.
Q2: What are typical ranges for Antoine constants?
A: A is usually 4-8, B is typically 1000-2000, and C is often 200-250, but varies by substance.
Q3: What temperature range is valid for the Antoine equation?
A: Each set of constants is valid only for a specific temperature range - check your source for validity limits.
Q4: Why does the equation use base-10 logarithm?
A: The original Antoine equation was formulated with base-10 logs, though some variations use natural logs.
Q5: How accurate is the Antoine equation?
A: It's typically accurate to within a few percent when used within its valid temperature range.
Q6: What are common applications of this calculation?
A: Distillation design, evaporation rate prediction, chemical process design, and environmental modeling.