Question

Balance the following equations, and indicate whether they are combination, decomposition, or combustion reactions: (a) \(\mathrm{C}_{3} \mathrm{H}_{6}(g)+\mathrm{O}_{2}(g) \longrightarrow \mathrm{CO}_{2}(g)+\mathrm{H}_{2} \mathrm{O}(g)\) (b) \(\mathrm{NH}_{4} \mathrm{NO}_{3}(s) \longrightarrow \mathrm{N}_{2} \mathrm{O}(g)+\mathrm{H}_{2} \mathrm{O}(g)\) (c) \(\mathrm{C}_{5} \mathrm{H}_{6} \mathrm{O}(l)+\mathrm{O}_{2}(g) \longrightarrow \mathrm{CO}_{2}(g)+\mathrm{H}_{2} \mathrm{O}(g)\) (d) \(\mathrm{N}_{2}(g)+\mathrm{H}_{2}(g) \longrightarrow \mathrm{NH}_{3}(g)\) (e) \(\mathrm{K}_{2} \mathrm{O}(s)+\mathrm{H}_{2} \mathrm{O}(l) \longrightarrow \mathrm{KOH}(a q)\)

Short answer

(a) Balanced equation: \(C_3H_6(g) + \frac{9}{2}O_2(g) \rightarrow 3CO_2(g) + 3H_2O(g)\) | Combustion (b) Balanced equation: \(NH_4NO_3(s) \rightarrow N_2O(g) + 2H_2O(g)\) | Decomposition (c) Balanced equation: \(C_5H_6O(l) + \frac{15}{2}O_2(g) \rightarrow 5CO_2(g) + 3H_2O(g)\) | Combustion (d) Balanced equation: \(N_2(g) + 3H_2(g) \rightarrow 2NH_3(g)\) | Combination (e) Balanced equation: \(K_2O(s) + H_2O(l) \rightarrow 2KOH(aq)\) | Combination

Step-by-step solution

Balancing the equation

To balance this chemical equation, we need to ensure that the number of atoms for each element on both sides of the equation are equal. Balanced equation: \(\mathrm{C}_{3} \mathrm{H}_{6}(g) +\dfrac{9}{2}\mathrm{O}_{2}(g) \longrightarrow 3\mathrm{CO}_{2}(g) +3\mathrm{H}_{2} \mathrm{O}(g)\)

Identifying the reaction type

A combustion reaction is characterized by reactants (usually a hydrocarbon) and oxygen, forming carbon dioxide and water. This equation fits that pattern making it a combustion reaction. (b) \(\mathrm{NH}_{4} \mathrm{NO}_{3}(s) \longrightarrow \mathrm{N}_{2} \mathrm{O}(g)+\mathrm{H}_{2} \mathrm{O}(g)\)

Balancing the equation

Balanced equation: \(\mathrm{NH}_{4} \mathrm{NO}_{3}(s) \longrightarrow \mathrm{N}_{2} \mathrm{O}(g) +2\mathrm{H}_{2} \mathrm{O}(g)\)

Identifying the reaction type

A decomposition reaction typically involves a single reactant being broken down into multiple products. This equation meets that requirement meaning it is a decomposition reaction. (c) \(\mathrm{C}_{5} \mathrm{H}_{6} \mathrm{O}(l)+\mathrm{O}_{2}(g) \longrightarrow \mathrm{CO}_{2}(g)+\mathrm{H}_{2} \mathrm{O}(g)\)

Balancing the equation

Balanced equation: \(\mathrm{C}_{5} \mathrm{H}_{6} \mathrm{O}(l) + \dfrac{15}{2}\mathrm{O}_{2}(g) \longrightarrow 5\mathrm{CO}_{2}(g) + 3\mathrm{H}_{2} \mathrm{O}(g)\)

Identifying the reaction type

This reaction also fits the pattern of a combustion reaction. (d) \(\mathrm{N}_{2}(g)+\mathrm{H}_{2}(g) \longrightarrow \mathrm{NH}_{3}(g)\)

Balancing the equation

Balanced equation: \(\mathrm{N}_{2}(g)+3\mathrm{H}_{2}(g) \longrightarrow 2\mathrm{NH}_{3}(g)\)

Identifying the reaction type

A combination reaction includes two or more reactants combining to form a single product. This reaction matches the pattern making it a combination reaction. (e) \(\mathrm{K}_{2} \mathrm{O}(s)+\mathrm{H}_{2} \mathrm{O}(l) \longrightarrow \mathrm{KOH}(a q)\)

Balancing the equation

Balanced equation: \(\mathrm{K}_{2} \mathrm{O}(s)+\mathrm{H}_{2} \mathrm{O}(l) \longrightarrow 2\mathrm{KOH}(a q)\)

Identifying the reaction type

This reaction also follows the pattern of a combination reaction, where the two reactants combine to form a single product.