Question

write a balanced reaction of nitrogen gas (molecular nitrogen) and hydrogen gas (molecular hydrogen) reacting and producing ammonia. which of the following statements about this reaction is incorrect?
to make 4 moles of ammonia 2 moles of nitrogen and 6 moles of hydrogen are needed
1 gram of nitrogen reacts with 3 grams of hydrogen producing 2 grams of ammonia
1 mole of nitrogen reacts with 3 moles of hydrogen producing 2 moles of ammonia
the stoichiometric ratio nitrogen : hydrogen is 1:3

Explanation:

Step1: Write the balanced chemical equation

The reaction between nitrogen gas ($N_2$) and hydrogen gas ($H_2$) to produce ammonia ($NH_3$) is $N_2 + 3H_2
ightarrow2NH_3$.

Step2: Analyze each statement

• For the statement "To make 4 moles of ammonia 2 moles of nitrogen and 6 moles of hydrogen are needed": From the balanced equation, the mole - ratio of $N_2:H_2:NH_3 = 1:3:2$. So, to make 4 moles of $NH_3$, since $\frac{n_{N_2}}{n_{NH_3}}=\frac{1}{2}$ and $\frac{n_{H_2}}{n_{NH_3}}=\frac{3}{2}$, $n_{N_2}=\frac{4}{2}=2$ moles and $n_{H_2}=\frac{4\times3}{2}=6$ moles. This statement is correct.
• For the statement "1 gram of nitrogen reacts with 3 grams of hydrogen producing 2 grams of ammonia": The molar mass of $N_2$ is $M_{N_2}=28$ g/mol and of $H_2$ is $M_{H_2} = 2$ g/mol and of $NH_3$ is $M_{NH_3}=17$ g/mol. From the balanced equation, 1 mole ($28$ g) of $N_2$ reacts with 3 moles ($6$ g) of $H_2$ to produce 2 moles ($34$ g) of $NH_3$. So, 1 gram of $N_2$ will not react with 3 grams of $H_2$ to produce 2 grams of $NH_3$. This statement is incorrect.
• For the statement "1 mole of nitrogen reacts with 3 moles of hydrogen producing 2 moles of ammonia": This is in accordance with the balanced chemical equation $N_2 + 3H_2

ightarrow2NH_3$. This statement is correct.

• For the statement "The stoichiometric ratio nitrogen : hydrogen is 1:3": From the balanced equation $N_2 + 3H_2

ightarrow2NH_3$, the stoichiometric ratio of $N_2$ to $H_2$ is 1:3. This statement is correct.

Answer:

1 gram of nitrogen reacts with 3 grams of hydrogen producing 2 grams of ammonia