2a)Using enthalpies of formation and other data, from the reference data provided below, calculate the net and gross calorific values for butane (C4H10) in units of MJ kmol-1 .

2b)The following data is obtained for a gas burner: Fuel: Butane (C4H10) Oxidant: Air Mixture: 3% fuel, 97% air (by volume) Fuel temperature: 15C Oxidant temperature: 160C Heat loss in combustion: 930 MJ kmol-1 (of fuel) Assume dissociation of the combustion products does not occur. Using your solution to part (a) and the reference data provided below, calculate:

The excess air in the fuel-oxidant mixture.

(ii) The oxygen content of the exhaust (vol%, dry).

(iii) The flame temperature.

Enthalpies of formation at 298K(MJkmol1) Specific heat (kJkq1K1) Sensible enthalpies (relative to zero at 298K)(kJkmol1)