**Bubble Point, Dew Point, and Flash Calculation**

To perform bubble and dew point calculation, first we must understand the theory of Raoult's Law for ideal mixture.

### Raoult's Law

Raoult's law states that the vapor pressure of a solvent above a solution is equal to the vapor pressure of the pure solvent at the same temperature scaled by the mole fraction of the solvent present. There are two major assumptions in Raoult's law, which are:

*The vapor phase is an ideal gas*, which means it can apply only from**low to moderate pressures**, and*The liquid phase is an ideal solution*, which means it only valid if the chemical species comprise are**chemically similar**.

### Bubble point, dew point, and flash calculations with Raoult's Law

There are five (5) classes to solve VLE problems

**BUBBLE P**: Calculate {\(y_i\)} and \(P\), given {\(x_i\)} and \(T\)**DEW P**: Calculate {\(x_i\)} and \(P\), given {\(y_i\)} and \(T\)**BUBBLE T**: Calculate {\(y_i\)} and \(T\), given {\(x_i\)} and \(P\)**DEW T**: Calculate {\(x_i\)} and \(T\), given {\(y_i\)} and \(P\)**P-T FLASH**: Calculate {\(x_i\)} and {\(y_i\)}, given \(P\) and \(T\)

**can't be calculated**if feed exists as

**subcooled liquid**or

**superheated vapor**.

### References

- Smith, J. M., Van Ness, H. C., Abbott, M. M., & Swihart, M. T. (2018). Introduction to Chemical Engineering Thermodynamics (8th ed.). McGraw-Hill.

**Bubble, Dew, and Flash Calculator**

See __how to use this calculator__ for step-by-step guide.

*Example problem*

Calculate the flash from a mixture of 15 mol water, 12 mol methanol, 22 mol ethanol, 36 mol propanol, and 15 mol acetone in a system of 1 bar and 50 degree Celsius!

If you find any issues, system errors, or have any feedback, please contact technology@torche.app