Phase Equilibrium Calculator Online
Calculate Vapor-Liquid Equilibrium (VLE) using Raoult's Law for ideal binary mixtures.
Equilibrium Results
What is Phase Equilibrium?
Phase equilibrium is a fundamental concept in chemical engineering and thermodynamics where multiple phases (such as solid, liquid, and gas) coexist at a specific temperature and pressure without any net change in their proportions. In a closed system, equilibrium is reached when the chemical potential of each component is equal across all present phases.
How to Use the Phase Equilibrium Calculator
This online tool utilizes Raoult's Law to predict the behavior of ideal binary mixtures. To get started, follow these steps:
- Pure Vapor Pressures: Enter the vapor pressures of pure Component A and Component B at the system's temperature. These can be found using the Antoine Equation.
- Mole Fraction: Input the liquid phase mole fraction of Component A (between 0 and 1). The tool automatically determines the fraction for Component B.
- Calculate: Click the calculate button to see partial pressures, total system pressure, and the resulting composition of the vapor phase (yA and yB).
Understanding Raoult's Law
Raoult's Law states that the partial vapor pressure of each component of an ideal mixture of liquids is equal to the vapor pressure of the pure component multiplied by its mole fraction in the mixture. It is represented by the formula: Pi = xi * P°i.
Frequently Asked Questions
What is an ideal mixture?
An ideal mixture is one where the intermolecular forces between different components are identical to those between similar molecules, meaning there is no heat of mixing or volume change upon mixing.
Why is the vapor mole fraction different from the liquid?
Because the components have different volatilities (pure vapor pressures), the more volatile component (the one with the higher vapor pressure) will be more concentrated in the vapor phase than it is in the liquid phase.
What are the limitations of this calculator?
This calculator assumes ideal behavior. For non-ideal mixtures (like ethanol and water), activity coefficients (Modified Raoult's Law) or Equation of State (EOS) models are required for accurate results.