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#### Raoult's Law and Vapor-Liquid Equilibrium: Screencast

Explains the shapes of the P-x-y and the T-x-y diagrams using Raoult’s Law.

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

##### Important Equations:

Antoine equation for component $$i$$: $\mathrm{log_{10}}(P_i ^{sat}) \,= \, A_i \, – \frac{B_i}{C_i+T}$ 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: $P \, = \sum P_i$

Bubble Pressure for a binary mixture: $P \, = \, x_1P_1^{sat} \, + \, x_2P_2^{sat}$ Where $$x_1$$ and $$x_2$$ are the liquid phase mole fractions corresponding to components 1 and 2.

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

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

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.

Raoult’s Law: $x_iP_i^{sat} \, = y_iP$ for each component $$i,$$ where $$x_i$$ is the liquid-phase mole fraction and $$y_i$$ is the vapor phase mole fraction.

Dew Pressure for a binary mixture: $\frac{y_1P}{P_1^{sat}}\,+\,\frac{y_2P}{P_2^{sat}}\, = \, 1$