...percent octane (C8H18), and 10 percent alcohol (C2H5OH), by moles. This fuel is burned with 200 percent theoretical dry air. Write the balanced reaction equation for complete combustion of this fuel mixture. Determine a) the theoretical air–fuel ratio for this reaction; b) the product–fuel ratio for this reaction; c) the air-flow rate for a fuel mixture flow rate of 5 kg/s; and d) the lower heating value of the fuel mixture with 200 per-cent theoretical air at 25°C.
What is "200 per-cent theoretical air"? Percent is a comparative term. You have to state what you are comparing with.
"Theoretical" usually means "hypothetical" but it can mean some other things and some of them are altogether wacko. You should explain this more carefully.
Moles are not divided into percents. A mole is a number of molecules, usually expressed as a mass or weight. You should explain this more carefully.