Respuesta :
on a molecular level there is a lot of movement which in turn is the reason why heat is generated.
Explanation:
A chemical reaction in which heat is absorbed by the reactant molecules is known as an endothermic reaction.
For example, [tex]A + B + Heat \rightarrow AB[/tex]
On the other hand, a chemical reaction in which heat energy is released by the reactant molecules is known as an exothermic reaction.
For example, [tex]A + B \rightarrow AB + Heat[/tex]
Thus, we can conclude that when an unknown substance undergoes a chemical change that gives off heat then it means earlier the substance has more heat energy but after the chemical change there occurs a decrease in its heat energy because some of the heat has been released by it.
