Questions

When a constant percentage of substrate is metabolized per unit time

INTEGRATED RATE LAW
radioactive decay follows first-order kinetics

This means the amount, N, of a radioactive substance (in kilograms) left after a time, t, can be calculated from the integrated rate law of a first-order reaction:

ln[(Nfinal)/(Ninitial)]=−kt

k: rate constant.

The rate constant can be calculated from the half-life:

k=(ln2)/(t half-life)
(Every other variable can be derived from the parent equation.)