The rate of a first order reaction is measured to be when the concentration of the reactant is exact — Chemical Kinetics Chemistry Question
Question
The rate of a first order reaction is measured to be $1.5 \times 10^{-2} \text{ mol L}^{-1} \text{ min}^{-1}$ when the concentration of the reactant is exactly $0.5 \text{ M}$. What is the theoretical half-life of this reaction?
Answer: B
💡 Solution & Explanation
For a first-order reaction, Rate $= k[A]$. $1.5 \times 10^{-2} = k \times 0.5 \Rightarrow k = 3.0 \times 10^{-2} \text{ min}^{-1}$. The half-life is given by $t_{1/2} = 0.693 / k = 0.693 / 0.03 = 23.1 \text{ minutes}$.
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