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The rate constant of a first-order reaction is 4 x 10⁻³ s⁻¹. When the reactant concentration is 0.02 M, what is the rate of the reaction?

8 x 10⁻⁵ M s⁻¹
4 x 10⁻³ M s⁻¹
2 x 10⁻¹ M s⁻¹
4 x 10⁻¹ M s⁻¹

Correct answer: 8 x 10⁻⁵ M s⁻¹

Solution

Rate = k[A] = (4 x 10⁻³)(0.02) = 8 x 10⁻⁵ M s⁻¹.

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