MCAT General Chemistry Question 217: Answer and Explanation
Home > MCAT Test > MCAT general chemistry practice tests
Test Information
- Use your browser's back button to return to your test results.
- Do more MCAT general chemistry practice tests.
Question: 217
2. Which of the following statements is always true about the kinetics of a chemical reaction?
- A. The rate law includes all reactants in the balanced overall equation.
- B. The overall order equals the sum of the reactant coefficients in the overall reaction.
- C. The overall order equals the sum of the reactant coefficients in the slow step of the reaction.
- D. The structure of the catalyst remains unchanged throughout the reaction progress.
Correct Answer: C
Explanation:
C Choice A is incorrect because rate laws are dependent on the slowest step. If a reactant does not participate in the slow step, it will not be included in the overall rate law. Choice B is incorrect because rate laws of overall reactions can only be determined experimentally. Choice D is incorrect because while it is true that a catalyst comes out of a reaction unchanged, it can undergo temporary transformations during the reaction and revert back into its original form at the end. Choice C is the best option because rate laws can be determined from elementary steps of a reaction mechanism by simply raising the reactants to their respective coefficients.