VLE Data Calculator: n-Heptane / n-Octane System

Author: Duran Flores Sandra Date: September 5, 2026

Instructions

This application automates Vapor-Liquid Equilibrium (VLE) calculations for a binary mixture of n-heptane (B) and n-octane (A) using high-density interpolated experimental data.

Total System Pressure: $P_{\text{total}} = 760 \text{ mmHg}$

Select any known parameter ($T$, $x_b$, or $y_b$), enter its value within the valid range, and click Calculate to evaluate the remaining equilibrium properties.

Mathematical Foundations

The equilibrium mole fractions are computed from vapor pressure data via Raoult's Law:

$$x_b = \frac{P_{\text{total}} - P_A^{\text{sat}}}{P_B^{\text{sat}} - P_A^{\text{sat}}}$$

$$y_b = \frac{x_b \cdot P_B^{\text{sat}}}{P_{\text{total}}}$$

Interpolation over fine sub-intervals ($\Delta T = 0.01 \text{ °C}$) guarantees numerical consistency and bi-directional accuracy across all state variables.

Select Known Parameter: Temperature, $T$ (°C) Liquid mole fraction of n-heptane, $x_b$ Vapor mole fraction of n-heptane, $y_b$

Enter Value (°C):

Equilibrium State Results

System Temperature ($T$)

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°C

Liquid Mole Fraction ($x_b$)

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mol n-heptane / mol

Vapor Mole Fraction ($y_b$)

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mol n-heptane / mol