The Raoult's Law calculator computes vapor pressure where solvent molecules can escape as a gas from a liquid solvent based on the mole fraction of solvent and the initial vapor pressure of solvent.
INSTRUCTIONS: Choose units and enter the following:
Partial Pressure (Pi): The calculator returns the pressure in atmospheres (atm). However, this can be automatically changed to compatible units via the pull-down menu.
The Raoult's Law[1] equation calculates the vapor pressure at which the solvent molecules are able to escape as from the liquid phase in to the gas phase, computed by a french chemist Francois-Marie Raoult(1830-1901). The evaporation of the solvent molecules depends on the increase of entropy[3], if solute is added to the solvent, the entropy is increased more causing less solvent molecules to escape in to the gas phase.
The Raoult's Law is calculated by:
`P_i =n_a/(n_a+n_b) * P_i^0`
where:
Note: This formula uses the mole fraction
`x_a =n_a/(n_a+n_b)`
where:
[1]https://en.wikipedia.org/wiki/Raoult%27s_law
[2]Whitten, et al. 10th Edition. Pp.518
[3]http://webs.morningside.edu/slaven/Physics/entropy/entropy7.html#note