Thermodynamics

Vapor-liquid equilibrium diagram of an ideal mixture

The following plot shows the vapor-liquid phase diagram for a binary ideal mixture (components: A and B). The vapor pressures of the pure substances are $p_A^*$ and $p_B^*$, respectively.

The blue curve shows the vapor pressure of the mixture $p$ as a function of the mole fraction of A in the liquid $x_A^l$:

$p=p_B^*+(p_A^*-p_B^*)\cdot x_A^l$

The red curve shows the vapor pressure of the mixture $p$ as a function of the mole fraction of A in the vapor $x_A^v$:

$p=p_A^*p_B^*/(p_A^*-(p_A^*-p_B^*)x_A^v)$

In the example below $p_A^*=1$ (a.u.) and the value of $p_B^*$ can be changed moving the slider below.

pB* (a.u.) =:

5

5