Question

Which piece of evidence would prove that a reaction is exothermic?

Answer 1

The reactants have more energy than the products. If a reaction is EXOthermic, it loses energy during the reaction, so the output (products) will have less energy than the input (reactants).

Answer 2

Answer: Option (c) is the correct answer.

Explanation:

In an exothermic reaction, excess of energy is released into the surroundings as a result there occurs decrease in the energy of products.

For example, $A + B \rightarrow C + D + Heat$ is an exothermic reaction.

Whereas in an endothermic reaction, energy is absorbed by reactant molecules and therefore, energy of products is more than energy of reactants.

For example, $A + B + Heat \rightarrow C + D$ is an endothermic reaction.

Thus, we can conclude that the reactants have more energy than the products is a piece of evidence that would prove that a reaction is exothermic.