Decomposition Reactant Half-Life and Rate Constant
What is the value and unit of the rate constant for this reaction?
When a reactant decomposes with a half-life of 129 seconds, the initial concentration is 0.131 M. However, when the initial concentration is 0.527 M, the same reactant decomposes with the same half-life of 129 s. What is the value and unit of the rate constant for this reaction?
Answer:
The rate constant for this reaction is 0.00537 s-1.
In order to determine the rate constant for this reaction, we can use the first-order reaction equation t1/2 = 0.693 / k, where t1/2 is the half-life and k is the rate constant. Given that the half-life is 129 seconds, we can substitute this value into the equation and solve for k:
t1/2 = 0.693 / k
129 = 0.693 / k
k = 0.693 / 129 = 0.00537 s-1
Therefore, the rate constant for this reaction is 0.00537 s-1.
The order of the reaction is determined by the half-life equation of a first-order reaction, which does not include a reactant concentration term. This means that the half-life is independent of concentration and remains constant throughout the reaction, indicating a first-order reaction.