mole fraction
posted by Kyle .
A solution contains a mixture of pentane and hexane at room temperature. The solution has a vapor pressure of 241 torr. Pure pentane and hexane have vapor pressures of 425 torr and 151 torr, respectively, at room temperature.
What is the mole fraction of hexane? (Assume ideal behavior.)

If x is the mole fraction pentane, 1x is the mole fraction of hexane.
Assume a molefractionweighted vapor pressure for the mixture.
425x + 151(1x) = 241
274 x = 90
Solve for x 
write the missing number in each fraction so that the fraction belongs in the box. write one more fraction that can go in the box.

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