Determine the fuel model cnhm- the composition of the fuel

Question

An unknown hydrocarbon material is burned in air for chemical analysis. An Orsat test indicates that the (dry) exhaust gas contains no CO or O₂ but consists of only 14.9% CO₂ and 85.1% N₂. Determine

a. The fuel model (C_nH_m).

b. The composition of the fuel on a percent mass basis.

c. The molar and mass air/fuel ratios used in the combustion process.

d. The dew point temperature if the combustion products are at 0.101 MPa.