Methane is burned with dry air in a steady-flow combustor. The volumetric analysis of the products on a dry basis is 5.2% CO2, 0.33% CO, 11.24% O2, and 83.23% N2. The methane and air enter the combustor at 298 K and 1 atm and the products exit at 1200 K and 1 atm. Determine (a) the air-fuel ratio, (b) the equivalence ratio, (c) the dew point of the product mixture, (d) the amount of energy transfer as heat (in kJ/kmol CH4), and (e) the entropy production rate during the combustion process (in kJ/kmol-K). The surroundings are at 298 K and 1 atm. Assume ideal gas behavior, and make allowance for variations in species specific heats with temperature.