Antoine Equation and Raoult's Law Calculations
This page focuses on the Antoine equation for calculating vapor pressures and provides a detailed example of Raoult's law calculations for a binary mixture.
The Antoine equation is used to calculate vapor pressures of pure species:
ln Pᵢˢᵃᵗ = Aᵢ - Bᵢ / T+Ci
Where Aᵢ, Bᵢ, and Cᵢ are Antoine constants specific to each species, and T is the temperature.
Example: The page presents a detailed example of Raoult's law calculations for a mixture of acetonitrile 1 and nitromethane 2 at 75°C.
Given:
- Temperature: 75°C
- Antoine constants for both species
The example demonstrates how to:
- Calculate pure component vapor pressures using the Antoine equation
- Determine vapor-phase compositions yi and total pressure P for different liquid-phase compositions xi
For instance, at x₁ = 0.2:
- P₁ˢᵃᵗ = 83.21 kPa
- P₂ˢᵃᵗ = 41.98 kPa
- P = x₁P₁ˢᵃᵗ + x₂P₂ˢᵃᵗ = 50.226 kPa
- y₁ = x₁P₁ˢᵃᵗ / P = 0.331
Highlight: This example illustrates the practical application of Raoult's law for vapor pressure calculations and demonstrates how composition affects the total pressure and vapor-phase composition in a binary mixture.
The page includes a table showing calculated values for different liquid-phase compositions, providing a comprehensive view of how the mixture behaves across its entire composition range.
