Heptane, C7H16, and octane form an ideal solution. At 40 degrees C, thevapor pressure of pure heptane is 0.522 atm, and the vapor pressure of pure octane is 0.238 atm. A solution is made of 5.32 g heptane and 8.8 g octane. Calculate the mole fraction of octane in the vapor at the above temperature.