Quiz – Stoichiometry

Have you mastered calculating reactants and products? Put your stoichiometry skills to the test with a quiz.

Your turn – stoichiometry calculations

1. \(\ce{CO}\) reacts with \(\ce{O}_{2}\) to form \(\ce{CO}_{2}\) gas as shown by the equation:
   \[2\ce{CO}+\ce{O}_{2}\rightarrow2\ce{CO}_{2}\]
1. Calculate the amount in moles of \(\ce{O2}\) required to react with \(0.58\textrm{ mol}\) of \(\ce{CO}\).

Answer

\(0.29\textrm{ mol}\)

2. Calculate the amount in moles of \(\ce{CO2}\) produced when \(0.35\textrm{ mol}\) or \(\ce{CO}\) reacts with \(\ce{O2}\).

Answer

\(0.35\textrm{ mol}\)

3. Calculate the amount in moles of \(\ce{O2}\) that must react with \(\ce{CO}\) to produce \(0.49\textrm{ mol}\) or \(\ce{CO2}\).

Answer

\(0.24\textrm{ mol}\)

2. The reaction between hydrazine and oxygen gas produces nitric oxide and water vapour according to the following balanced chemical equation:
   \[\ce{N}_{2}\ce{H}_{4}\left(\textrm{l}\right)+3\ce{O}_{2}\left(\textrm{g}\right)\rightarrow2\ce{NO}_{2}\left(\textrm{g}\right)+2\ce{H}_{2}\ce{O}\left(\textrm{g}\right)\]
1. Calculate the amount in moles of \(\ce{O}_{2}\) required to react with \(0.6\textrm{ mol}\) of \(\ce{N}_{2}\ce{H}_{4}\).

Answer

\(2\textrm{ mol}\)

2. Calculate the amount in moles of \(\ce{N}_{2}\ce{H}_{2}\) that must react with \(\ce{O}_{2}\) to form \(0.4\textrm{ mol}\) of \(\ce{NO}_{2}\).

Answer

\(0.2\textrm{ mol}\)

3. Calculate the mass of \(\ce{O}_{2}\) required to form \(10.50\textrm{ g}\) of \(\ce{CO}_{2}\) from the reaction between methane and oxygen:
   \[\ce{CH}_{4}+2\ce{O}_{2}\rightarrow\ce{CO}_{2}+2\ce{H}_{2}\ce{O}\]
   The molar masses of \(\ce{CO}_{2}\) and \(\ce{O}_{2}\) are \(44.01\textrm{ g mol}^{-1}\) and \(32.00\textrm{ g mol}^{-1}\).

4. Consider the equation for the following chemical reaction:
   \[3\ce{H}_{2}\left(\textrm{g}\right)+\ce{N}_{2}\left(\textrm{g}\right)\rightarrow2\ce{NH}_{3}\left(\textrm{g}\right)\]
   Calculate the mass of \(\ce{N}_{2}\) required to produce \(48.5\textrm{ g}\) of \(\ce{NH}_{3}\). The molar masses of \(\ce{NH}_{3}\) and \(\ce{N}_{2}\) are \(17.03\textrm{ g mol}^{-1}\) and \(28.02\textrm{ g mol}^{-1}\).

5. Sulfur dioxide gas is produced by the reaction between sulfur and oxygen:
   \[\ce{S}+\ce{O}_{2}\rightarrow\ce{SO}_{2}\]
   \(12.8\textrm{ g}\) of \(\ce{S}\) reacts with \(18.5\textrm{ g}\) of \(\ce{O}_{2}\). The molar masses of \(\ce{S}\) and \(\ce{O}_{2}\) are \(32.07\textrm{ g mol}^{-1}\) and \(32.00\textrm{ g mol}^{-1}\), respectively. The molar mass of \(\ce{SO2}\) is \(64.07\textrm{ g mol}^{-1}\).
1. Identify the limiting reagent.

Answer

\(\ce{S}\)

2. Calculate the maximum mass of \(\ce{SO}_{2}\) that can be formed under the given conditions.

Answer

\(25.63\textrm{ g}\)

6. \(\ce{HCl}\) is formed according to the following reaction.
   \[\ce{H}_{2}+\ce{Cl}_{2}\rightarrow2\ce{HCl}\]
   Calculate the maximum mass of \(\ce{HCl}\) that can be produced when \(0.85\textrm{ g}\) of \(\ce{H}_{2}\) reacts with \(42.58\textrm{ g}\) of \(\ce{Cl}_{2}\). The atomic molar masses of \(\ce{H}\) and \(\ce{Cl}\) are \(1.01\textrm{ g mol}^{-1}\) and \(35.45\textrm{g mol}^{-1}\).

7. Calcium nitrite (\(\ce{Ca}_{3}\ce{N}_{2}\)) is produced using \(\ce{Ca}\) and \(\ce{N}_{2}\) as follows:
   \[3\ce{Ca}+\ce{N}_{2}\rightarrow\ce{Ca}_{3}\ce{N}_{2}\]
   Calculate the theoretical yield of \(\ce{Ca}_{3}\ce{N}_{2}\) when \(120.56\textrm{ g}\) of \(\ce{Ca}\) is reacted with \(42.87\textrm{ g}\) of \(\ce{N}_{2}\). The atomic molar mass of \(\ce{Ca}\) is \(40.08\textrm{g mol}^{-1}\), and the atomic molar mass of \(\ce{N}\) is \(14.01\textrm{g mol}^{-1}\). The molar mass of \(\ce{Ca}_{3}\ce{N}_{2}\) is \(148.26\textrm{g mol}^{-1}\).

8. Salicylic acid (\(\ce{C}_{7}\ce{H}_{6}\ce{O}_{3}\)) reacts with acetic anhydride (\(\ce{C}_{4}\ce{H}_{6}\ce{O}_{3}\)) to form acetylsalicylic acid (\(\ce{C}_{9}\ce{H}_{8}\ce{O}_{4}\)), which we call aspirin.
   \[2\ce{C}_{7}\ce{H}_{6}\ce{O}_{3}+\ce{C}_{4}\ce{H}_{6}\ce{O}_{3}\rightarrow2\ce{C}_{9}\ce{H}_{8}\ce{O}_{4}+\ce{H}_{2}\ce{O}\]
   The percentage yield of aspirin from the reaction is \(88.48\%\). Determine the mass of aspirin that was actually formed by the reaction of \(250.82\textrm{ g}\) of salicylic acid. The molar masses of salicylic acid and acetylsalicylate acid are \(138.21\textrm{ g mol}^{-1}\) and \(180.16\textrm{ g}\), respectively.