Final answer:
The reaction is exothermic because the energy released in the formation of the products is greater than the energy required to break the bonds in the reactants.
Step-by-step explanation:
An exothermic reaction occurs when the energy required to break bonds in the reactants is less than the energy released when the products are formed. In this case, the ΔH for the reactants is -750 kJ/mol and the ΔH for the products is 920 kJ/mol. Since the energy released in the formation of the products is greater than the energy required to break the bonds in the reactants, this reaction is exothermic.