#### Vapor-Liquid Equilibrium for Non-Ideal Solutions: Screencast

Explains how to calculate bubble pressure, dew pressure, bubble temperature, and dew temperature for vapor-liquid equilibrium for a binary solution that is non-ideal.

We suggest you list the important points in this screencast as a way to increase retention.

Explains what an activity coefficient is for components in non-ideal liquid solutions.

We suggest you list the important points in this screencast as a way to increase retention.

##### Important Equations:

Antoine equation for component $$i$$: $log_{10}(P_i ^{sat}) \,= \, A_i \, – \frac{B_i}{C_i+T}$ Where $$P_i^{sat}$$ is the saturation pressure, $$T$$ is the temperature (most often in $$^oC$$), and $$A_i, B_i,$$ and $$C_i$$ are constants for a given component, $$i$$.

The total pressure, $$P$$, is the sum of partial pressures: $P \, = \sum P_i$

Relative volatility $$\alpha:$$ $\alpha\,=\,\frac{K_1}{K_2}\,=\,\frac{y_1/x_1}{y_2/x_2}$

Where $$K_1$$ is the K-factor for component 1 (equal to $$y_1/x_1$$ where $$y_1$$ is the vapor mole fraction of component 1 and $$x_1$$ is the liquid mole fraction of component 1). Likewise $$K_2$$ is the K-factor for component 2.

Gibbs Phase Rule for non-reactive system: $F \, = \, 2 \, + \, C \, – P$ where $$F$$ is the number of degrees of freedom, $$C$$ is the number of components, and $$P$$ is the number of phases.

Bubble Pressure for a binary mixture: $P \, = \, x_1\gamma_1P_1^{sat} \, + \, x_2\gamma_2P_2^{sat}$ Where $$x_1$$ and $$x_2$$ are the liquid phase mole fractions corresponding to components 1 and 2, $$\gamma_1$$ and $$\gamma_2$$ are the activity coefficients of components 1 and 2.

Dew Pressure for a binary mixture: $P\, = \,\frac{1}{\frac{y_1}{\gamma_1P_1^{sat}}+\frac{y_2}{\gamma_2P_2^{sat}}}$

Components in the vapor phase:$y_1 \, + y_2 \, = 1$

Components in the liquid phase:$x_1 \, + x_2 \, = 1$