[spKelpDiver]

A solution contains naphthalene (C₁₀H₈)dissolved in hexane (C₆H₁₄)  at a concentration of 14.59% naphthalene by mass. Calculate the vapor pressure at 25C  of hexane above the solution. The vapor pressure of pure hexane at 25C  is 151 torr .

It has to be the summer, because this problem shouldn't have me stumped. I know the equation is P_soln=χ_solventP_solvent.

I am having trouble pulling the mole fraction of the solvent (hexane) out of the percent by mass relationship. I know there are 14.59g (C₁₀H₈)/100g solution. I know this is relatively easy, but I am stumped. Can anybody help me see the way here?

I know that a mol fraction has to add up to 1. I tried subtracting .1459 from 1 = .8541. I then multiplied that by 151. Mastering chemistry told me I was close but wrong, and to check my calculations for sig fig errors.

[Borek]

If there is 14.59g of naphthalene in 100g of the mixture, how many grams of hexane are there?

[spKelpDiver]

85.41...seriously, the summer has made me rusty! I was overthinking it. I just got it. 135 torr. Thanks for the *delete me*

[spKelpDiver]

*delete me* ? LOL! First post and I am already beginning to understand the way things work around here.