Answer: Change in concentration over time.
- A Change in mass over time
- B Change in concentration over time
- C Change in temperature over time
- D Change in pressure over time
Correct answer: B. Change in concentration over time
Explanation: Rate = change in concentration of reactant or product per unit time.
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.