A typical air bag contains approximately $50 g$ of sodium azide and some potassium nitrate to avoid explosion by burning of sodium. What is the amount (in g) of potassium nitrate required?

$$\begin{gathered} 2Na{N}_3\to 2Na+3N_2 \\ 2KN{O}_3+10Na\to K_{2}O+5N{a}_{2}O+N_2 \\ 10Na{N}_3\to 10Na+15N_2 \\ 10Na{N}_3+2KN{O}_3\to K_{2}O+5N{a}_{2}O+16N_2 \\ 10\times 65 2\times 101 \\ 650 202 \\ 50 ? \\ \frac{202}{13}=15.538\cong 16 \end{gathered}$$