Question

`One way to make ammonia is to synthesize it directly from elemental nitrogen and hydrogen (though this isn't that easy). The equation for this reaction would be N2 + 3 H2 → 2 NH3. If you are able to stream in 7.0 g of N2, what would be the minimum amount of H2 in grams that would be required to completely react with this amount of N2?

A. 1.5 g
B. 0.5 g
C. 0.75 g
D. 3.0 g
E. none of the above

Answer 1

Answer:  A. 1.5 g

Explanation:

$N_2+3H_2\rightarrow 2NH_3$

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

$\text{Number of moles of nitrogen}=\frac{7.0g}{28g/mol}=0.25 moles$

According to stoichiometry:

1 mole of $N_2$ requires = 3 moles of $H_2$

Thus 0.25 moles of $N_2$ will require =$\frac{3}{1}\times 0.25=0.75moles$ of $H_2$

Mass of $H_2$ required =$moles\times {\text {Molar mass}}=0.75mol\times 2g/mol=1.5g$

The minimum amount of $H_2$ in grams that would be required to completely react with this amount of $N_2$ is 1.5 grams.

Answer 2

Answer:

The correct answer is option A.

Explanation:

$N_2 + 3 H_2\rightarrow 2 NH_3$

Moles of nitrogen gas = $\frac{7.0 g}{28 g/mol}=0.25 mol$

According to reaction, 1 mole of nitrogen reacts with 3 moles of hydrogen gas.

Then 0.25 moles of nitrogen gas will react with:

$\frac{3}{1}\times 0.25 mol=0.75 mol$ of hydrogen gas.

Mass of 0.75 moles of hydrogen gas = 0.75 mol × 2 g/mol = 1.5 g

1.5 grams of hydrogen that would be required to completely react with this amount of nitrogen.