Question 3 Air bubbles through a drum containing a liquid mixture of n-hexane (C6H14) and n- heptane (C7H16) at 25 C. The initial composition of the liquid is 50 mol% of n-hexane and 50 mol% of n-heptane. Assume the gas leaving the drum is saturated with n-hexane and n-heptane vapor and air is not dissolved in liquid. Calculate the composition of the initial gas bubble. If a gas mixture of such a composition is to be combusted with 20% excess air, how much additional air is needed per 100 mol of the gas mixture? The pressure of the gas leaving the drum is 1 atm. Vapor pressure of pure n-hexane (A) and n-heptane (B) can be estimated from Antoine equation: 1175.817 logio P/(mm Hg) = 6.88555 - T(C)+224.867 1267.828 logio P(mm Hg) = 6.90253 T(C)+216.823 (15 marks)