Final answer:
The half-life of a first-order reaction is a constant that is related to the rate constant for the reaction.
Step-by-step explanation:
The half-life of a reaction is the time required for the reactant concentration to decrease to one-half its initial value. The half-life of a first-order reaction is a constant that is related to the rate constant for the reaction: t₁/2 = 0.693/k.