A first-order reaction has a half-life of 1386 s. What is the rate constant for this reaction?

0.5 × 10⁻² s⁻¹
0.5 × 10⁻³ s⁻¹
5.0 × 10⁻² s⁻¹
5.0 × 10⁻³ s⁻¹

Correct answer: 0.5 × 10⁻³ s⁻¹

Solution

The rate constant for a first-order reaction can be calculated using the formula k = 0.693/t₁/₂, where t₁/₂ is the half-life. Substituting 1386 s into the formula gives a rate constant of approximately 0.5 × 10⁻³ s⁻¹.

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