Iron reacts with oxygen in a chemical hand-warmer. how should this reaction be categorized?
a. as an exothermic process because it releases heat
b. as an endothermic process because it releases heat
c. as an exothermic process because it absorbs heat
d. as an endothermic process because it absorbs heat

The correct answer is option A.

Explanation:

Exothermic reactions are defined as the reactions in which the energy of reactants is more than the energy of the products. In these reactions, energy is released by the system. The total enthalpy of the reaction comes out to be negative.

The warmness of our hands in the chemical hand-warmer is due to the heat energy released on the reaction of iron and oxygen. This heat energy released is absorbed by our hands which makes our hands warm.  

Since energy is released during the reaction this reaction be categorized as an exothermic  

Endothermic reactions are defined as the reactions in which the energy of products is more than the energy of the reactants. In these reactions, energy is absorbed by the system. The total enthalpy of the reaction comes out to be positive.