Answer: 4 x 10-3 s-1.
- A 1 x 10-3 s-1
- B 2 x 10-3 s-1
- C 8 x 10-3 s-1
- D 4 x 10-3 s-1
Correct answer: D. 4 x 10-3 s-1
Explanation: k = rate/[A] = (2 x 10-3)/0.5 = 4 x 10-3 s-1 (first order, so unit is s-1).
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.