Balancing equations Knowledge-Based Practice

Questions

1. 1.

   Which of the following chemical equations is correctly balanced?

   • A) $2\text{Fe}(s) + 3\text{Cl}_2(g) \rightarrow \text{FeCl}_3(s)$
   • B) $2\text{Na}(s) + 2\text{H}_2\text{O}(l) \rightarrow 2\text{NaOH}(aq) + \text{H}_2(g)$
   • C) $\text{Mg}(s) + \text{HCl}(aq) \rightarrow \text{MgCl}_2(aq) + \text{H}_2(g)$
   • D) $\text{CH}_4(g) + 2\text{O}_2(g) \rightarrow \text{CO}_2(g) + \text{H}_2\text{O}(g)$
2. 2.

   Which set of stoichiometric coefficients correctly balances the chemical equation for the combustion of ethane when using the lowest whole numbers, in the order of reactants and products: $\text{C}_2\text{H}_6(g) + \text{O}_2(g) \rightarrow \text{CO}_2(g) + \text{H}_2\text{O}(g)$?

   • A) 2, 7, 4, 6
   • B) 1, 7, 2, 3
   • C) 2, 5, 4, 6
   • D) 1, 5, 2, 3
3. 3.

   When the chemical equation $\text{CuO}(s) + \text{NH}_3(g) \rightarrow \text{Cu}(s) + \text{N}_2(g) + \text{H}_2\text{O}(l)$ is balanced using the lowest whole-number coefficients, what is the stoichiometric ratio of $\text{CuO}$ to $\text{N}_2$?

   • A) 2 : 1
   • B) 3 : 1
   • C) 1 : 1
   • D) 3 : 2
4. 4.

   When the chemical equation $\text{Al}(s) + \text{H}_2\text{SO}_4(aq) \rightarrow \text{Al}_2(\text{SO}_4)_3(aq) + \text{H}_2(g)$ is balanced using the smallest whole-number coefficients, what is the sum of all coefficients?

   • A) 7
   • B) 9
   • C) 8
   • D) 11
5. 5.

   When the chemical equation $\text{NH}_3(g) + \text{O}_2(g) \rightarrow \text{NO}(g) + \text{H}_2\text{O}(g)$ is balanced using the lowest whole-number coefficients, what is the stoichiometric coefficient of $\text{O}_2(g)$?

   • A) 5
   • B) 4
   • C) 3
   • D) 6

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