mols EtOH = g/molar mass = ?
mols H2O = g/molar mass = ?
Total mols = mols EtOH + mols H2O = ?
XEtOH = mols EtOH/total mols = ?
XH2O = mols H2O/total mols = ?
pEtOH = XEtOH*PoEtOH = ?
pH2O = XH2O*PoH2O = ?
Then Ptotal above the solution is pEtOH + pH2O
Post your work if you get stuck.
Please help!
The vapor pressure of water at 35 oC is 42.175 mm Hg. The vapor pressure of ethyl alcohol (C2H5OH) at 35 C is 100.5 mm Hg. What is the vapor pressure of a solution prepared by dissolving 250 g of C2H5OH in 375 g of H2O?
The answer is supposed to be 48.3 mm Hg but I don't know how to get there!
2 answers
Here's my resulting answer but it isn't 48.3 mm Hg
mols EtOH = g/molar mass = 5.43 mols
mols H2O = g/molar mass = 20.81 mols
Total mols = mols EtOH + mols H2O = 26.24 mols
XEtOH = mols EtOH/total mols = 0.207 mol
XH2O = mols H2O/total mols = 0.793 mol
pEtOH = XEtOH*PoEtOH = 20.80 mmHg
pH2O = XH2O*PoH2O = 33.45 mmHg
Total Pressure = 54.25 mm Hg
mols EtOH = g/molar mass = 5.43 mols
mols H2O = g/molar mass = 20.81 mols
Total mols = mols EtOH + mols H2O = 26.24 mols
XEtOH = mols EtOH/total mols = 0.207 mol
XH2O = mols H2O/total mols = 0.793 mol
pEtOH = XEtOH*PoEtOH = 20.80 mmHg
pH2O = XH2O*PoH2O = 33.45 mmHg
Total Pressure = 54.25 mm Hg