Question

The rate constant for a first-order reaction is 0.54 M-1s-1. What is the half-life of this reaction if the initial concentration is 0.27 M?

a.) 1.3 s
b.) 0.25 s
c.) 5.0 s
d.) 2.0 s
e.) 6.9 s

Answer 1

The half-life of a first-order reaction with a rate constant of 0.54 M-1s-1 is calculated using the formula t1/2 = 0.693/k. After substituting the rate constant, the half-life can be determined.

Step-by-step explanation:

The student asked about the half-life of a first-order reaction with a rate constant of 0.54 M-1s-1. The half-life (t1/2) of a first-order reaction is a constant and is calculated using the formula t1/2 = 0.693/k. Here, the rate constant k is given as 0.54 M-1s-1, so we can substitute this into the formula.

t1/2 = 0.693 / 0.54 M-1s-1

Calculating the above expression gives us a half-life for this reaction. However, it is important to recognize that the question has a minor error. It lists the rate constant with units of M-1s-1 which would typically indicate a second-order reaction, yet it refers to the reaction as first-order. The correct units for a first-order reaction would be s-1. Assuming the question intends a first-order reaction, we follow the provided calculation assuming the units are s-1.