Question

The vapor pressure of diethyl ether is 463.57 mm Hg at 25 degrees celsius. How many grams of aspirin C9H8O4, a non volatile nonelectrolyte (mw=180.1g/mol), must be added to 216.7g of ether to reduce the vapor pressure to 453.74 mm Hg.

Ether=74.12g/mol


so I did 463.57 - 453.74 = 7.600

Then I found moles of ether to be 4.0313.

I do not understand the next step to find Xether.

Answer 1

You had better subtract again. 7.600 is not right.
You need the mole fraction of ether. You get that by
pether = Xether*Po ether
You know partial pressure of ether to be 453.74 (that's what you want it to be)
You know Po ether to be 463.57. Solve for Xether.

Answer 2

I subtracted again and got 9.83.

So do I set it up like this

453.74= Xether * 463.57

Answer 3

Disregard question.