$\begin{gathered}2 \mathrm{NaN}_3(s) \rightarrow 2 \mathrm{Na}(s)+3 \mathrm{~N}_2(g) \\ ? \mathrm{~mol} \mathrm{~N}_2=70 \mathrm{~L} \mathrm{~N}_2 \times \frac{0 / 8 \mathrm{~g}}{1 \mathrm{~L}} \times \frac{1 \mathrm{~mol}}{28 \mathrm{~g}}=2 \mathrm{~mol} \mathrm{~N}_2 \\ \bar{R}_{N_2}=\frac{|\Delta n|}{\Delta t}=\frac{2}{\frac{0 / 008}{60}}=15000 \mathrm{~mol} \cdot \mathrm{~min}^{-1} \\ \bar{R}_{\mathrm{NaN}_3}=\frac{2}{3} \bar{R}_{N_2}=\frac{2}{3} \times 15000=10000 \mathrm{~mol} \cdot \mathrm{~min}^{-1}\end{gathered}$