Answer: The reaction is exothermic and therefore the heat is released by the reaction.
Explanation:
There are 2 types of reaction based on the heat of the reaction:
For the given chemical reaction:
[tex]4Al(s)+3O_2(g)\rightarrow 2Al_2O_3(s);\Delta H^o=-3351kJ[/tex]
As, the enthalpy change of the reaction is negative. The reaction is considered as an exothermic reaction.
Hence, the reaction is exothermic and therefore the heat is released by the reaction.