The sum of the mole fractions of each of the substances present always equals one. The mole fraction of the solute is therefore 1-.8=.2.
(15) How many moles of solute are present?
The mole fraction of the solvent is generally defined as the ratio of the moles of solvent to the total number of moles present. The total number of moles present is equal to the sum of the moles of solvent and the moles of solute. With the mole fraction of solvent and number of moles of solvent already determined, the number of moles of solute can be found. Let x represent the number of moles of solute.
