Chemistry Help

[theogcasey]

Need help with chem 2. Hopefully someone has an idea...

Calculate the vapor pressure (in torr) at 310 K in a solution prepared by dissolving 23.8 g of the non-volatile non-electrolyte sucrose in 126 g of water. The vapor pressure of water at 310 K is 47.08 torr.

Thanks.

[Egghead]

sorry I cant help... you should try posting this on yahoo answers

[Bandwagoner]

Originally Posted by theogcasey Need help with chem 2. Hopefully someone has an idea... Calculate the vapor pressure (in torr) at 310 K in a solution prepared by dissolving 23.8 g of the non-volatile non-electrolyte sucrose in 126 g of water. The vapor pressure of water at 310 K is 47.08 torr. Thanks.

http://en.wikipedia.org/wiki/Raoult's_law

[justtxyank]

If you want to help chemistry you need to dump the oft-injured cancer. It's hard to focus when you have a whining petulant child clouding the future of your organization.

[Bandwagoner]

Crap! Why did I help you? i just realized I hate you. You stole my name. I am the OG casey as you can clearly see from my join date

[Xcellerator]

P = X solvent * P solvent
X solvent = moles of solvent/total moles
Molar mass of water = 18 g/mol
Moles of solvent (water) = 126/18 = 7 moles

Molar mass of sucrose = 342.3 g/mol
Moles of solute (sucrose) = 23.8g/342.3 = .06953

Total moles = 7.06953 moles

X solvent = moles of water/total moles = 7 mol/7.06952 mol = .990166

P = X solvent * P solvent = .990166 * (47.08 torr) = 46.617 ~ 46.6 torr (3 sig figs)

Hope that's right. Just had a test over it along with other stuff.

[theogcasey]

Originally Posted by Xcellerator P = X solvent * P solvent X solvent = moles of solvent/total moles Molar mass of water = 18 g/mol Moles of solvent (water) = 126/18 = 7 moles Molar mass of sucrose = 342.3 g/mol Moles of solute (sucrose) = 23.8g/342.3 = .06953 Total moles = 7.06953 moles X solvent = moles of water/total moles = 7 mol/7.06952 mol = .990166 P = X solvent * P solvent = .990166 * (47.08 torr) = 46.617 ~ 46.6 torr (3 sig figs) Hope that's right. Just had a test over it along with other stuff.

Thanks a bunch! I accidentally used the moles of sucrose instead of water... Dumb.

[Xcellerator]

Originally Posted by theogcasey Thanks a bunch! I accidentally used the moles of sucrose instead of water... Dumb.

Well, if you use moles of sucrose, you can subtract its torr from the water torr and still get the answer.

[kikimama]

Originally Posted by Xcellerator Well, if you use moles of sucrose, you can subtract its torr from the water torr and still get the answer.

yeah but the solenoids of the thearcheia won't be viable