Answer
a. $N_{2}$(g)+ 3$H_{2}$(g)$\longrightarrow$ 2$NH_{3}$ (g)
b. Hydrogen molecules $H_{2}$ represent the limiting reactant.
c. 6 molecules $H_{2}$.
Work Step by Step
a. Chemical equation:
$N_{2}$(g)+ $H_{2}$(g)$\longrightarrow$ $NH_{3}$ (g)
To balance add 2 before $NH_{3}$ and 3 before $H_{2}$
$N_{2}$(g)+ 3$H_{2}$(g)$\longrightarrow$ 2$NH_{3}$ (g)
b. We see in the picture that there are molecules of $NH_{3}$ and molecules of $N_{2}$ in the container, but no molecules of $H_{2}$. A chemicals reactions has happened between $H_{2}$ and $N_{2}$ , resulting in $NH_{3}$.
All molecules of hydrogen that were in container have entered in this chemical reaction. There are no molecules of hydrogen left in the container to react with the remaining nitrogen molecules. Therefore hydrogen molecules $H_{2}$ represent the limiting reactant.
c. Based on the picture there are 2 molecules of nitrogen in the container. To convert it to ammonia we need to add hydrogen molecules.
Based on the balanced chemical equation, the ratio is
1 molecule $N_{2}$(g): 3 molecules $H_{2}$(g).
Therefore for 2 molecules of $N_{2}$ we need to add 6 molecules $H_{2}$.
