(TB 5.6) 2. Butane (C4H10) is fed to a fired heater at a molar flow rate of 100 mol/h and 50% excess air to partially combusted (Hint: two independent chemical reactions!). Only 50% of the butane is consumed, and the product gas contains 9 mol CO2 per mol CO. Calculate the molar flow rates of all components in the stack gas leaving the fired heater (i.e. C4H10, O2, N2, H₂O, CO2, and CO).