How to Determine the Order of a Reaction and the Rate Constant?

What is the order of the reaction?

What is the value and unit of the rate constant for this reaction?

Answer:

The order of the reaction is 1 (first-order) because the half-life is constant regardless of the initial concentration. The rate constant (k) of the reaction is approximately 0.0054 per second (s^-1).

Explanation: The reaction is clearly a first-order reaction because the half-life is constant and does not depend on the initial concentration of the reactant. For a first-order reaction, the half-life (t1/2) is related to the rate constant (k) by a simple formula: t1/2 = 0.693/k. Substituting the given half-life into this equation gives k = 0.693 / 129s ≈ 0.0054 s-1. So, the value of the rate constant for this reaction is 0.0054 and its unit is s^-1.