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A substance undergoes decomposition according to first-order kinetics. If its concentration falls to one-eighth of the initial concentration in 24 minutes, what is the rate constant for the process?
- 1/24 min⁻¹
- 0.692 / 24 min⁻¹
- 2.303 / 24 log(1/8) min⁻¹
- 2.303 / 24 log(8/1) min⁻¹
Correct answer: 2.303 / 24 log(8/1) min⁻¹
Solution
The correct option uses the first-order kinetics formula, which relates the rate constant to the logarithm of the ratio of initial and final concentrations. Since the concentration falls to one-eighth, the logarithm of 8/1 is used, reflecting the change in concentration over the given time period.
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