Question

Using Raoul's Law, predict the partial pressures in the vapor above a solution containing 0.30 mol acetone (p degree = 340) torr and 0.30 mol chloroform (p degree = 295 torr)

Answer 1

For a solution of two liquids, A and B, Raoult's law predicts that if no other gases are present, then the total vapor pressure above the solution is equal to the weighted sum of the "pure" vapor pressures of the two components, $p_A$ and $p_B$ . Thus the total pressure above the solution of A and B would be

$p = p^{\star}_{\rm A} x_{\rm A} + p^{\star}_{\rm B} x_{\rm B}.$

mole fraction = moles gas / total moles in mixture

p=0.5*340 + 0.5*295 =317.5torr.mol

Partial pressure(Pp) =mol fraction *total pressure

Pp(acetone)=158.75torr=Pp(choloform)