Waste streams from various processes in a complex chemical facility are combined and burned for heat, because the cost of purifying and recycling the components is prohibitive. On a typical day, the combined waste stream contains 2 mol% acetone (CH3)2CO, 14 mol% acetic anhydride (CH3CO)2O, 36 mol% methane (CH4), 20 mol% ethane (C2H6), 13 mol% N2, 4 mol% O2, 8 mol% CO, and 3 mol% H2S. The waste stream is fed to a furnace along with 20% excess air and combusted. (For combustion reactions, excess air is calculated on the assumption that the only products of combustion are CO2, H2O, N2 and SO2). Analysis of the exit flue gas gives a CO2/CO mass ratio of 4:1. The only other components in the flue gas are N2, O2, H2O and SO2. Calculate the composition of the exit flue gas. Assume air is 21 mol% O2 and 79 mol% N2.

Answer: 4.6% O2 , 70.9% N2, 3% CO, 7.7%CO2, 13.5% H2O, 0.22% SO2 (all mol %) I never get this numbers HELP!!