Answer: decreases k.
- A increases k
- B decreases k
- C does not change k
- D doubles k
Correct answer: B. decreases k
Explanation: A larger Ea makes the exponential term smaller, so the rate constant k decreases.
First-order decay curve: concentration halves every t½, and that half-life is constant - a defining test for first-order kinetics.
Concept context
Study the speed of reactions and what affects it: concentration, temperature, and catalysts. Covers rate law, order of reaction, the Arrhenius equation, and reaction mechanisms step by step.