Consider the following reaction: $$ 4 \mathrm{NH}_{3}(\mathrm{~g})+5 \mathrm{O}_{2}(g) \longrightarrow 4 \mathrm{NO}(g)+6 \mathrm{H}_{2} \mathrm{O}(g) $$ If a container were to have 10 molecules of \(\mathrm{O}_{2}\) and 10 molecules of \(\mathrm{NH}_{3}\) initially, how many total molecules (reactants plus products) would be present in the container after this reaction goes to completion?

To identify the limiting reactant, we will compare the initial number of molecules of each reactant to the stoichiometric coefficients in the balanced chemical equation. The reactant that has fewer molecules than required by the stoichiometry is the limiting reactant, which determines the extent of the reaction. For every 4 molecules of NH3, we need 5 molecules of O2 according to the balanced chemical equation. Given initial molecules: - NH3 (g): 10 molecules - O2 (g): 10 molecules For the 10 molecules of NH3, required molecules of O2: (10 molecules of NH3) x (5 molecules of O2 / 4 molecules of NH3) = 12.5 molecules of O2 Since we have only 10 molecules of O2, which is less than the required 12.5 molecules, O2 is the limiting reactant.

Now that we've identified the limiting reactant, we can calculate the number of molecules of each product formed when the reaction goes to completion: For the 10 molecules of O2, amount of NO formed: (10 molecules of O2) x (4 molecules of NO / 5 molecules of O2) = 8 molecules of NO For the 10 molecules of O2, amount of H2O formed: (10 molecules of O2) x (6 molecules of H2O / 5 molecules of O2) = 12 molecules of H2O

We also need to find out how many molecules of NH3 remain unreacted after the reaction goes to completion: Amount of NH3 consumed: (10 molecules of O2) x (4 molecules of NH3 / 5 molecules of O2) = 8 molecules of NH3 Remaining NH3 molecules: 10 molecules (initial) - 8 molecules (consumed) = 2 molecules

Finally, we can add the number of molecules of each reactant and product after the reaction goes to completion to find the total number of molecules: Total molecules = molecules of unreacted NH3 + unreacted O2 + molecules of NO + molecules of H2O Total molecules = 2 molecules (NH3) + 0 molecules (O2) + 8 molecules (NO) + 12 molecules (H2O) Total molecules = 22 molecules So, there are 22 total molecules (reactants plus products) in the container after the reaction goes to completion.