Final answer:
The rate constant of a first-order process with a half-life of 225 s is approximately 0.0031 s^-1.
Step-by-step explanation:
The rate constant of a first-order process can be determined from its half-life. The half-life of a first-order reaction is the time taken for the concentration of the reactant to decrease by half. In this case, the half-life is given as 225 s. The rate constant (k) can be calculated using the formula:
k = ln(2) / t1/2
Substituting the given value of the half-life into the formula:
k = ln(2) / 225 s
k = 0.693 / 225 s
k ≈ 0.0031 s^-1