Question

A solution is prepared by adding 1g of sugar mannitol (MW 182.2g/g-mole) in 100g of water at 20◦C. (a) Assuming that mannitol and water form an ideal solution, what is the equilibrium vapor pressure of solution? The vapor pressure of pure water is 17.54mmHg at 20◦C

Answer 1

mols manitol = grams/molar mass = ?
mols H2O = grams/molar mass = ?
Find total mols by adding.

Then find mol fraction H2O = mols H2O/total mols.
Then Psoln = X_H2O*P^o_{pure H2O}