Substance A reacts spontaneously with substance B at room temperature. Substance A reacts with substance C at room temperature only in the presence of a catalyst. Which statement best explains this difference?(1 point)
The reaction between substances A and B has a lower relative potential energy than the reaction between substances B and C.
The reaction between substances A and B has a lower activation energy than the reaction between substances B and C.
The reaction between substances A and B is exothermic.
The reaction between substances A and B is endothermic.
doses no one have these answers
The statement that best explains the difference is: "The reaction between substances A and B has a lower activation energy than the reaction between substances B and C."
To determine the best statement that explains the difference in reactions, we first need to understand a few concepts.
The relative potential energy is a measure of the energy stored in the chemical bonds of a substance. Lower relative potential energy means the bonds in the reactants are more stable compared to the bonds in the products.
Activation energy is the minimum energy required for a chemical reaction to occur. It represents the energy barrier that must be overcome for the reactants to reach the transition state and form products.
Exothermic reactions release energy in the form of heat, while endothermic reactions absorb energy from the surroundings.
Given this information, we can evaluate the statements:
1. "The reaction between substances A and B has a lower relative potential energy than the reaction between substances B and C." - This statement does not directly address the activation energy or the presence of a catalyst. It focuses on relative potential energy, which may not necessarily explain the observed difference in reactivity.
2. "The reaction between substances A and B has a lower activation energy than the reaction between substances B and C." - This statement provides a plausible explanation for the difference in reactivity. A lower activation energy means that the reaction between A and B can occur more readily at room temperature, while the reaction between A and C requires the presence of a catalyst to lower its activation energy and make it feasible.
3. "The reaction between substances A and B is exothermic." - This statement solely describes the energy change during the reaction, without addressing the difference in reactivity or the presence of a catalyst. Therefore, it does not provide an adequate explanation for the difference.
4. "The reaction between substances A and B is endothermic." - This statement, like the previous one, focuses on the energy change rather than the difference in reactivity or the role of a catalyst. Thus, it does not provide a satisfactory explanation.
Therefore, the statement that best explains the difference in reactivity is: "The reaction between substances A and B has a lower activation energy than the reaction between substances B and C."