Respuesta :

Answer:

The explanation to your question is below.

Explanation:

In thermochemistry, reactions are classify in two groups.

- Endothermic reactions: are reactions that need energy (heat) from the surroundings to happen. If they are not heated, the products will not form.

Example:

                        2 H₂O + energy ⇒ 2H₂  + O₂

-Exothermic reactions: are reactions that release energy to the surroundings. They happen spontaneously.

Example:

                       CH₄  + 2O₂   ⇒   CO₂   +  2H₂O + energy (heat)