Question

If there were 3.4mol of nitrogen gas, how many moles of hydrogen gas would be needed to use it up to make ammonia gas (nitrogen trihydride)? How much (in moles of) ammonia gas would be formed?

Answer 1

N_{2 (g)} + 3H_{2 (g)} -------------------------> 2NH_{3 (g)}

_{(3.4 mol)}

Considering the stoichiometry,

1.

$\qquad\qquad \begin {aligned} \frac{n_{N_2}}{n_{H_2}} &= \frac{1}{3}\\ \\ \frac{3.4}{n_{H_2}} &= \frac{1}{3}\\ \\ n_{H_2} &= \bold{10.2\, mol} \end {aligned}$

2.

$\qquad\qquad \begin {aligned} \frac{n_{N_2}}{n_{NH_3}} &= \frac{1}{2}\\ \\ \frac{3.4}{n_{NH_3}} &= \frac{1}{2}\\ \\ n_{NH_3} &= \bold{6.8\, mol} \end{aligned}$