Question

question 6 of 30
the diagram below shows how the potential energy changes during a
chemical reaction. what can you tell about the reaction from the diagram?

a. the reaction is endothermic because it has a low activation
energy.

b. the reaction is endothermic because the reactants are higher in
energy than the products.

c. the reaction is exothermic because it has a low activation energy.

d. the reaction is exothermic because the reactants are higher in
energy than the products.

Explanation:

1. Recall the definitions of exothermic and endothermic reactions:

• Exothermic reactions release energy, so the potential energy of reactants is higher than that of products (reactants → products, energy decreases).
• Endothermic reactions absorb energy, so the potential energy of products is higher than that of reactants (reactants → products, energy increases).

1. Analyze the diagram: The potential energy of reactants (initial) is higher than that of products (final).
2. Evaluate each option:

• Option A: Endothermic is incorrect (reactants have higher energy), and activation energy is not the reason for endothermic/exothermic. Eliminate A.
• Option B: Endothermic is incorrect (reactants are higher, so energy is released, exothermic). Eliminate B.
• Option C: Activation energy does not determine exothermicity; it's about energy change between reactants and products. Eliminate C.
• Option D: Correct. The reaction is exothermic because reactants have higher energy than products (energy is released).

Answer:

D. The reaction is exothermic because the reactants are higher in energy than the products.