The rate equation for the decomposition of $\mathrm{N}_{2} \mathrm{O}_{5}$ (giving $\mathrm{NO}_{2}$ and $\mathrm{O}_{2}$ ) is Rate $=k\left[\mathrm{N}_{2} \mathrm{O}_{5}\right] .$ The value of $k$ is $6.7 \times 10^{-5} \mathrm{s}^{-1}$ for the reaction at a particular temperature.
(a) Calculate the half-life of $\mathrm{N}_{2} \mathrm{O}_{5}$.
(b) How long does it take for the $\mathrm{N}_{2} \mathrm{O}_{5}$ concentration to drop to one tenth of its original value?