Question

using the graph, explain how activation energy works. how is it similar to creating fire with a matchstick? how do you compare the energy in these two graphs showing endothermic and exothermic reactions?

Explanation:

Activation energy is the minimum energy required for a chemical reaction to occur. In the energy diagram, it is the energy barrier (the peak) that reactants ($X + Y$) must overcome to form products ($XY$). Just like creating fire with a matchstick, where you provide an initial energy (striking the match) to overcome the activation energy for the combustion reaction (similar to the energy needed to start the reaction in the diagram).

For the endothermic and exothermic reactions:

• In an exothermic reaction (first lower - left graph), the energy of the products ($XY$) is lower than the energy of the reactants ($X + Y$). The energy released is the difference between the energy of reactants and products.
• In an endothermic reaction (lower - right graph), the energy of the products ($X + Y$) is higher than the energy of the reactants ($XY$). Energy is absorbed during the reaction, which is the difference between the energy of products and reactants.

Answer:

Activation energy is the energy barrier reactants must overcome. Striking a match provides initial energy (like activation energy). For energy comparison: exothermic - products have lower energy; endothermic - products have higher energy.