Question

$450c{m}^3$of nitrogen monoxide and $200c{m}^3$of oxygen are mixed together and ignited. Calculate the composition of the resulting mixture?

Answer 1

• The balanced equation when is mixed with oxygen is:

$$\begin{gathered} 2\mathrm{NO}\left(g\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)\to 2{\mathrm{NO}}_2\left(\mathrm{g}\right) \\ \mathrm{Nitrogen}\mathrm{Oxygen}\mathrm{Nitrogen} \\ \mathrm{monoxide}\mathrm{dioxide} \end{gathered}$$

• Calculating the volume of $\mathrm{NO}$

$2$ vols of $\mathrm{NO}$ require ${\mathrm{O}}_2$$=1$vol

$1$vol of ${\mathrm{O}}_2$ is used for the combustion of $\mathrm{NO}$ $=2$ vol

Now $200cc$ of ${\mathrm{O}}_2$ is used for the combustion of $\mathrm{NO}$ $$\begin{gathered} =200\times 2 \\ =400cc \end{gathered}$$

Now volume of $\mathrm{NO}$ left unused $$\begin{gathered} =450-400 \\ =50cc \end{gathered}$$

• Calculating the volume of ${\mathrm{NO}}_2$produced

$1$ vol of ${\mathrm{O}}_2$ on reaction produces ${\mathrm{NO}}_2$$$\begin{gathered} =2\times 200 \\ =400cc \end{gathered}$$

• Thus the volume of ${\mathrm{NO}}_2$ produced is $400cc$and the volume of $\mathrm{NO}$ left unused is $50cc$