Pentane gas at 25C, 150 kPa enters an insulated SSSF combustion chamber. Sufficient excess air to hold

Question:

Pentane gas at 25C, 150 kPa enters an insulated SSSF combustion chamber. Sufficient excess air to hold the combustion products temperature to 1800 K enters separately at 500 K, 150 kPa. Calculate the percent theoretical air required and the irreversibility of the process per kmol of pentane burned.