When 8.00 × 1022 molecules of ammonia react with 7.00 × 1022 molecules of oxygen according to the chemical equation shown below, how many grams of nitrogen gas are produced?

4 NH3(g) + 3 O2(g) → 2 N2(g) + 6 H2O(g)

Verified Answer :

Answer: 1.848 g

Explanation: To calculate the moles, we use the equation:

\(\text{Number of moles}=\frac{\text{Given molecules}}{\text {Avogadro's number}}\)    ....(1)

For ammonia:

Putting values in above equation, we get:

\(\text{Moles of ammonia}=\frac{8.00\times 10^{22}}{6.023\times 10^{23}}=0.132mol\)

\(\text{Moles of oxygen}=\frac{7.00times 10^{22}}{6.023\times 10^{23}}=0.116mol\)

For the reaction:

\(4NH_3(g)+3O_2(g)\rightarrow 2N_2(g)+6H_2O(g)\)

By Stoichiometry of the reaction,

4 moles of ammonia combine with 3 moles of Oxygen

Thus 0.132 moles of ammonia will combine with=\(\frac{3}{4}\times 0.132=0.009mol\) of oxygen

Thus ammonia is the limiting reagent as it limits the formation of product.

4 moles of ammonia produces 2 moles of nitrogen

0.132 moles of ammonia will produce=\(\frac{2}{4}\times 0.132=0.066 moles\) of nitrogen

Molar mass of nitrogen =  28 g/mol

Amount of nitrogen produced=\({text {no of moles}}\times {text {molar mass}}=0.066\times 28=1.848g\)