Bubble point

In thermodynamics, the bubble point is the temperature (at a given pressure) where the first bubble of vapor is formed when heating a liquid consisting of two or more components.

[1][2] Given that vapor will probably have a different composition than the liquid, the bubble point (along with the dew point) at different compositions are useful data when designing distillation systems.

where K is the distribution coefficient or K factor, defined as the ratio of mole fraction in the vapor phase

When Raoult's law and Dalton's law hold for the mixture, the K factor is defined as the ratio of the vapor pressure to the total pressure of the system:[1] Given either of

and either the temperature or pressure of a two-component system, calculations can be performed to determine the unknown information.