For a first-order reaction, the half-life is constant. It depends only on the rate constant kkk and not on the reactant

[answerhappygod]

For a first-order reaction, the half-life is constant. It
depends only on the rate
constant kkk and not on the reactant
concentration. It is expressed as
t1/2=0.693kt1/2=0.693k
For a second-order reaction, the half-life depends on the rate
constant and the concentration of the reactant
and so is expressed as
t1/2=1k[A]0t1/2=1k[A]0
Part A
A certain first-order reaction (A→productsA→products) has a rate
constant of 5.10×10−3 s−1s−1 at 45 ∘C∘C.
How many minutes does it take for the concentration of the
reactant, [A][A], to drop to 6.25%% of the original
concentration?