Answer: Remain almost unchanged.
- A Increase very sharply
- B Remain almost unchanged
- C Fall to zero at once
- D Double for every degree
Correct answer: B. Remain almost unchanged
Explanation: In k = A e<sup>-Ea/RT</sup>, if Ea = 0 then e<sup>0</sup> = 1 and k = A, independent of temperature, so k stays almost unchanged.
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.