Determine the fuel model cnhm - the percent mass

Question

The Orsat analysis of the (dry) exhaust gas from the combustion of an unknown hydrocarbon is 1.10% CO₂, 1.10% CO, 18.8% O₂, and 79.0% N₂. Determine

a) The fuel model (C_nH_m),

b) The percent mass composition of the fuel,

c) The fuel/air ratio used, and

d) The dew point temperature at 0.644 MPa.