[somesortoftimemachine]

calculate vapor pressure in mmHg @ 25C of water above a solution made by dissolving 100. g of C12H22O11 in 250. grams of water. the vapor pressure of pure water @ 25C is 23.8 mmHg

ok...so i am trying to use the ol' P_A=X_AP*_A...raoult's law
so  C12H22O11=342.3g/mol
so 100g C12H22O11(1 mol/342.3g)=.2921mols
250g water(1mol/18.02)=13.87mols.. .2921/(.2921+13.87)=X_A=.02063

is the vapor pressure of pure water (23.8 mmHg) my partial pressure?
if so then its sooooo easy right? i just P_A/X_A right??!
23.8/.02063.....WORNG!!!
help please, before i poke i eyes out with a pencil