wini

A solution is made by dissolving 46.5g of urea, (CH4N2O) a nonelectrolyte, in 316g of water. Calculate the vapour pressure of this solution at 40 oC. (ans in torr, note the vapour pressure of pure water at 40 oC is 55.3 torr.) I have been struggling with...

I finally got it right..

Now suppose, instead, that the solute in problem 6 is volatile and that the pure solute displays, at 90 oC, a vapour pressure of 52.580 torr. Calculate the molar mass (in g) for this case. This is the second part to this question

First You convert 645.0 torr to atm, and also mL to L. You use PV=nRT, to find the number of moles. Then you use the number of moles to get the molar mass. mol= mass/molar mass