Determine the actual molar and mass airfuel ratios- the

Question

The following dry exhaust volumetric analysis results from the combustion of an unknown amount of octane (x moles of C₈H₁₈) in a spark ignition internal combustion engine: 8.80% CO₂, 8.20% CO, 4.1% H₂, 1.00% NO, 0.200% CH₄, and 77.7% N₂. Determine

a. The actual molar and mass air/fuel ratios.

b. The percent of theoretical air used.

c. The molar percentage of water vapor in the exhaust gas before it was dried for this analysis.