Question

A bottle of rubbing alcohol (C3H7OH) from the store is a 70% solution by mass. Determine the total vapor pressure inside the closed bottle. The vapor pressure of the water at room temperature is 24mmHg; the vapor pressure of the volatile rubbing alcohol is 44mmHg.

Answer 1

70% alcohol by mass means 70 g alcohol + 30 g water.
Convert 70 g alcohol to mols.
Convert 30 g water to mols.
Determine mole fraction of alcohol.
Determine mole fraction water.
P_alcohol=X_alcohol*P^o_alcohol.
P<sub>H2O</sub=X_H2OP^o_water.
Total pressure is sum of partial pressures. Post your work if you get stuck. Check my thinking. I have some superscripts and subscripts involved here; if they don't turn out properly I will post a correction.

Answer 2

PH2O</sub=X_H2OP^o_water.
shoud be on the front part,
P_H2O= etc.