91Ó°ÊÓ

The gases from a wood-burning stove are found to contain \(1.8 \%\) carbon monoxide at a temperature of \(65^{\circ} \mathrm{C}\), Express the concentration in units of \(\mu \mathrm{g} \mathrm{m}^{-3}\).

Which of the following atmospheric species are free radicals? $$ \mathrm{OH}, \mathrm{O}_{3}, \mathrm{Cl}, \mathrm{ClO}, \mathrm{CO}, \mathrm{NO}, \mathrm{N}_{2} \mathrm{O}, \mathrm{NO}_{3}^{-}, \mathrm{N}_{2} \mathrm{O}_{5} $$

In an indoor atmosphere, for \(\mathrm{NO}_{2}\) the value of the first order rate constant has been estimated to be \(1.28 \mathrm{~h}^{-1}\). Calculate its residence time.

If the rate laws are expressed using \(\mathrm{mol} \mathrm{L}^{-1}\) for concentrations and \(\mathrm{Pa}\) for pressure, what are the units of the second and third order rate constants, \(k_{2}\) and \(k_{3}\) ? Calculate the conversion factor for converting \(k_{2}\) values obtained in the units above to ones using molecules per \(\mathrm{cm}^{3}\) for concentration and atm for pressure.

For the reaction $$ \mathrm{NO}+\mathrm{O}_{3} \rightarrow \mathrm{NO}_{2}+\mathrm{O}_{2} $$ the second order rate constant has a value of \(1.8 \times 10^{-14} \mathrm{molecules}^{-1} \mathrm{~cm}^{3} \mathrm{~s}^{-1}\) at \(25^{-} \mathrm{C}\). The concentration of NO in a relatively clean atmosphere is \(0.10 \mathrm{ppbv}\) and that of \(\mathrm{O}_{3}\) is \(15 \mathrm{ppbv}\). Convert these two concentrations into units of molecules \(\mathrm{cm}^{-3}\). Calculate the rate of the NO oxidation using units of molecules \(\mathrm{cm}^{-3} \mathrm{~s}^{-1}\). Show how the rate law may be expressed in pseudo first order terms and calculate the corresponding pseudo first order rate constant.