posted by Melissa .
Estimate the vapor pressure of sea water at 20C given that the vapor pressure of pure water is 2.338 kPa at that temperature and the solute is largely Na+ and Cl- ions, each present in about .50 mol/dm^3.
I'm pretty sure the formula to use is pj=xjpj'. Where pj' is the vapor pressure of a pure substance, but I can't figure out how to solve for the mole fractions on the sodium and chlorine. Thanks