Which of the following aspects is typically different in a catalyzed reaction compared to an uncatalyzed reaction?

• A. The identities of the reactants and products
• B. The overall enthalpy change (ΔH) of the reaction
• C. The stoichiometry of the reaction
• D. The activation energy of the reaction

Answer: (D)

Verified step by step guidance

1. Understand that a catalyst provides an alternative reaction pathway with a lower activation energy, which speeds up the reaction without being consumed.
2. Recognize that the identities of the reactants and products remain unchanged because the catalyst does not alter the chemical nature of the substances involved.
3. Recall that the overall enthalpy change (\$\Delta H\$) of the reaction is a state function and depends only on the initial and final states, so it remains the same whether catalyzed or not.
4. Note that the stoichiometry of the reaction, which describes the relative amounts of reactants and products, is also unchanged by the presence of a catalyst.
5. Conclude that the key difference in a catalyzed reaction compared to an uncatalyzed one is the activation energy, which is lowered by the catalyst, facilitating a faster reaction rate.