## Chemistry (7th Edition)

$2.79\times10^{-3} s^{-1}$
Recall that $t_{1/2}=\frac{0.693}{k}$ or $k=\frac{0.693}{t_{1/2}}$. That is, $k=\frac{0.693}{248 s}=2.79\times10^{-3}s^{-1}$