Balancing equations Transitional Reasoning Practice

Questions

1. 1.

   In an emergency submarine life-support canister, solid sodium peroxide reacts with exhaled carbon dioxide to produce solid sodium carbonate and breathable oxygen gas according to the unbalanced equation $\text{Na}_2\text{O}_2\text{(s)} + \text{CO}_2\text{(g)} \rightarrow \text{Na}_2\text{CO}_3\text{(s)} + \text{O}_2\text{(g)}$. To determine the canister's gas replenishment efficiency, an environmental systems technician balances the chemical equation using the smallest whole-number coefficients. What is the stoichiometric coefficient of $\text{Na}_2\text{CO}_3\text{(s)}$, and what is the mole ratio of consumed $\text{CO}_2\text{(g)}$ to generated $\text{O}_2\text{(g)}$, respectively?

   • A) 1 and 1 : 1
   • B) 2 and 1 : 2
   • C) 2 and 2 : 1
   • D) 4 and 1 : 1
2. 2.

   During the storage of agricultural fumigants, solid calcium phosphide ($\text{Ca}_3\text{P}_2$) can accidentally react with atmospheric moisture to release gaseous phosphine ($\text{PH}_3$) and solid calcium hydroxide ($\text{Ca(OH)}_2$) according to the unbalanced equation $\text{Ca}_3\text{P}_2\text{(s)} + \text{H}_2\text{O(l)} \rightarrow \text{Ca(OH)}_2\text{(s)} + \text{PH}_3\text{(g)}$. To assess the ventilation hazard, a safety technician must balance this equation using the smallest whole-number coefficients. Which of the following statements regarding the properly balanced equation is correct?

   • A) The stoichiometric coefficient of $\text{H}_2\text{O}$ is equal to the sum of the stoichiometric coefficients of all products.
   • B) Balancing the phosphorus atoms requires assigning a stoichiometric coefficient of 3 to $\text{PH}_3$.
   • C) The sum of all reactant coefficients is strictly less than the sum of all product coefficients.
   • D) For every 1 mole of $\text{Ca}_3\text{P}_2$ consumed, 6 moles of $\text{H}_2\text{O}$ are required and 2 moles of $\text{PH}_3$ are produced.
3. 3.

   In an industrial high-temperature reduction process, elemental phosphorus is extracted from phosphate rock according to the unbalanced chemical equation $\text{Ca}_3(\text{PO}_4)_2\text{(s)} + \text{SiO}_2\text{(s)} + \text{C(s)} \rightarrow \text{CaSiO}_3\text{(s)} + \text{P}_4\text{(s)} + \text{CO(g)}$. An engineer needs to determine the material balance to ensure complete reduction and accurately monitor gas emissions. When this chemical equation is balanced using the smallest whole-number coefficients, what are the stoichiometric coefficient of $\text{C(s)}$ and the sum of the stoichiometric coefficients of all products, respectively?

   • A) 8 and 15
   • B) 10 and 17
   • C) 5 and 11
   • D) 10 and 35
4. 4.

   In an industrial exhaust treatment process, nitrogen monoxide is converted into harmless nitrogen gas and water vapor by reacting with ammonia: $\text{NH}_3\text{(g)} + \text{NO(g)} \rightarrow \text{N}_2\text{(g)} + \text{H}_2\text{O(g)}$. When this chemical equation is balanced using the smallest whole-number coefficients, what are the stoichiometric coefficients of $\text{NH}_3$ and $\text{N}_2$, respectively?

   • A) 2 and 3
   • B) 4 and 6
   • C) 4 and 5
   • D) 6 and 5
5. 5.

   During an industrial roasting process, solid pyrite reacts with oxygen according to the unbalanced reaction equation $\text{FeS}_2\text{(s)} + \text{O}_2\text{(g)} \rightarrow \text{Fe}_2\text{O}_3\text{(s)} + \text{SO}_2\text{(g)}$. To determine the stoichiometry of the air feed, an engineer balances this equation using the lowest whole-number coefficients. What is the stoichiometric coefficient of $\text{O}_2$ and the total sum of all reactant and product coefficients, respectively?

   • A) 11 and 25
   • B) 11 and 21
   • C) 7 and 17
   • D) 5 and 15

Answers and step-by-step solutions appear after you finish the test.