When combining the two intermediate steps of the reactions:
[tex]\[
\begin{array}{l}
\text{1)} \ N_2(g) + O_2(g) \longrightarrow 2 \ NO(g) \\
\text{2)} \ 2 \ NO(g) + O_2(g) \longrightarrow 2 \ NO_2(g)
\end{array}
\][/tex]
we need to carefully account for the oxygen molecules (O[tex]\(_2\)[/tex]) involved in both reactions.
In the first reaction:
[tex]\[
N_2(g) + O_2(g) \longrightarrow 2 \ NO(g)
\][/tex]
one molecule of O[tex]\(_2\)[/tex] is a reactant.
In the second reaction:
[tex]\[
2 \ NO(g) + O_2(g) \longrightarrow 2 \ NO_2(g)
\][/tex]
another molecule of O[tex]\(_2\)[/tex] is a reactant.
When combining the reactions, there is no canceling out of oxygen molecules (O[tex]\(_2\)[/tex]) because they are reactants in both steps. Therefore, we must sum the oxygen molecules from both reactions.
Based on the steps above, Jason should account for both O[tex]\(_2\)[/tex] molecules as reactants.
Hence, the correct answer is:
Place two of them as reactants.
