whenever energy is released in a chemical reaction, we would then expect the delta H of the reaction to be negative because the reaction is an exothermic reaction.
now we have that 2.81 moles of fuel when it combusts would releases 1612kJ of energy
thus, 1 mole will release 1612/2.81 = -573.67kJ of heat
Therefore the delta H of the reaction = -573.67 kJ/mol
