1,2-Benzanthracene is a yellow-brown nonvolatile solid with molecular weight 228.29g*mol-1. an 18.2632-g sample of 1,2-benzanthracene is dissolved in 250.0 g of benzene, C6H6. Whta is the vapor pressure of this solution at 25C, in millimeters of mergury, if the vapor pressure of pure benzene is 93.4 mmHg at this temperature?

Question

1,2-Benzanthracene is a yellow-brown nonvolatile solid with molecular weight 228.29g*mol-1. an 18.2632-g sample of 1,2-benzanthracene is dissolved in 250.0 g of benzene, C6H6. Whta is the vapor pressure of this solution at 25C, in millimeters of mergury, if the vapor pressure of pure benzene is 93.4 mmHg at this temperature?
a)60.8
b)91.1
c)93.4
d)95.7
e)760

This was on my last test but i got it wrong. This is for test corrections and the right answer is (b) but i have absolutely no idea how to do this. Thank you so much for whoever attempts to help. :)

DrBob222 · Answer

Yes, the answer is b.
mols BZth = grams/molar mass = ?
mols benzene = grams/molar mass = ?
Xbenzene = mols benzene/total mols.

Then pbenzene soln = Xbenzene*Pbenzene where Pbenzene is 93.4 mm = normal vapor pressure.