combustion analysis

[sawhai]

A fuel oil burned in a steam generator has a composition that may be represented as C₁₅H₃₂.

A dry basis analysis of the flue gas yields the following molar composition: CO₂ 10.111%,
CO 1.000%, O₂
5.611%, and N₂ 83.278%.

Determine the following:
(a). The percent excess air used to burn the fuel oil;
(b). The flue gas molar composition on a wet basis, reporting all constituents, including
water vapor, to the nearest 0.001%; and
(c). The dew point temperature (°C) of the flue gas, if the pressure exiting the combustion

I am trying to balance the combustion equation:
aC₅H₃₂ + bO₂ + cN₂ = 10.111CO₂ + 1.000CO + 5.611O₂ + 83.278N₂ + dH₂O

Any idea of how to do it considering #N₂=#O₂*3.76 ?

Thanks
stack is 180 kPa

[expert]

Separate your equation into independent reactions and balance each. After that you can mix these reactions in any required proportions.
C₅H₃₂ + O₂ = CO₂ + H₂O
C₅H₃₂ + O₂ = CO + H₂O
Add nitrogen in required proportion: it is not participating in burning process, so it should be equal and unchanged in the reagents and in the products.