Chapter 9, Problem 9.72P

Interpretation Introduction

Interpretation:

Time required to reduce radioactive nitrogen-16 from 100 mg to a final amount of 6.25 mg should be determined.

Concept Introduction:

Radioactive decays follow first-order reaction kinetics.

For a first-order reaction the equation is:

$\text{l}n{\left[\text{a}\right]}_t=\text{l}n{\left[\text{a}\right]}_{\text{O}}–\lambda t$

where,

[A]_t = concentration of substrate at time ‘t’.

[A]_o = initial concentration of substrate at time ‘t=0’.

t = elapsed time.

$\lambda$ =decay constant.