Question

Complete and balance the following equations: $$\begin{array}{l}{\text { (a) } \mathrm{CaO}(s)+\mathrm{H}_{2} \mathrm{O}(l) \longrightarrow} \\ {\text { (b) } \mathrm{Al}_{2} \mathrm{O}_{3}(s)+\mathrm{H}^{+}(a q) \longrightarrow} \\\ {\text { (c) } \mathrm{Na}_{2} \mathrm{O}_{2}(s)+\mathrm{H}_{2} \mathrm{O}(l) \longrightarrow}\end{array}$$ $$ \begin{array}{l}{\text {(d) } \mathrm{N}_{2} \mathrm{O}_{3}(g)+\mathrm{H}_{2} \mathrm{O}(l) \longrightarrow} \\ {\text { (e) } \mathrm{KO}_{2}(s)+\mathrm{H}_{2} \mathrm{O}(l) \longrightarrow} \\ {\text { (f) } \mathrm{NO}(g)+\mathrm{O}_{3}(g) \longrightarrow}\end{array} $$

Short answer

The balanced equations are: (a) \(\mathrm{CaO}(s)+\mathrm{H}_{2} \mathrm{O}(l) \longrightarrow \mathrm{Ca(OH)}_{2}(s)\) (b) \(\mathrm{Al}_{2} \mathrm{O}_{3}(s)+6\mathrm{H}^{+}(a q) \longrightarrow 2\mathrm{Al}^{3+}(a q)+3\mathrm{H}_{2} \mathrm{O}(l)\) (c) \(\mathrm{Na}_{2} \mathrm{O}_{2}(s)+2\mathrm{H}_{2} \mathrm{O}(l) \longrightarrow 2\mathrm{NaOH}(a q)+\mathrm{O}_{2}(g)\) (d) \(\mathrm{N}_{2} \mathrm{O}_{3}(g)+\mathrm{H}_{2} \mathrm{O}(l) \longrightarrow 2\mathrm{HNO}_{3}(a q)\) (e) \(2\mathrm{KO}_{2}(s)+2\mathrm{H}_{2} \mathrm{O}(l) \longrightarrow 2\mathrm{KOH}(a q)+\mathrm{O}_{2}(g)+2\mathrm{H}_{2} \mathrm{O}_{2}(l)\) (f) \(\mathrm{NO}(g)+\mathrm{O}_{3}(g) \longrightarrow \mathrm{NO}_{2}(g)+\mathrm{O}_{2}(g)\)

Step-by-step solution

Equation (a) Completion

The given equation is: $$\mathrm{CaO}(s)+\mathrm{H}_{2} \mathrm{O}(l) \longrightarrow?$$ Calcium oxide (CaO) reacts with water (H₂O) to produce calcium hydroxide (Ca(OH)₂): $$\mathrm{CaO}(s)+\mathrm{H}_{2} \mathrm{O}(l) \longrightarrow \mathrm{Ca(OH)}_{2}(s)$$

Equation (a) Balancing

The equation is already balanced.

Equation (b) Completion

The given equation is: $$\mathrm{Al}_{2} \mathrm{O}_{3}(s)+\mathrm{H}^{+}(a q) \longrightarrow?$$ Aluminum oxide (Al₂O₃) reacts with hydrogen ions (H⁺) to produce aluminum ions (Al³⁺) and water (H₂O): $$\mathrm{Al}_{2} \mathrm{O}_{3}(s)+\mathrm{H}^{+}(a q) \longrightarrow \mathrm{Al}^{3+}(a q)+\mathrm{H}_{2} \mathrm{O}(l)$$

Equation (b) Balancing

Balancing the equation, we get: $$\mathrm{Al}_{2} \mathrm{O}_{3}(s)+6\mathrm{H}^{+}(a q) \longrightarrow 2\mathrm{Al}^{3+}(a q)+3\mathrm{H}_{2} \mathrm{O}(l)$$

Equation (c) Completion

Given equation: $$\mathrm{Na}_{2} \mathrm{O}_{2}(s)+\mathrm{H}_{2} \mathrm{O}(l) \longrightarrow?$$ Sodium peroxide (Na₂O₂) reacts with water (H₂O) to produce sodium hydroxide (NaOH) and oxygen (O₂) gas: $$\mathrm{Na}_{2} \mathrm{O}_{2}(s)+\mathrm{H}_{2} \mathrm{O}(l) \longrightarrow \mathrm{NaOH}(a q)+\mathrm{O}_{2}(g)$$

Equation (c) Balancing

Balanced equation: $$\mathrm{Na}_{2} \mathrm{O}_{2}(s)+2\mathrm{H}_{2} \mathrm{O}(l) \longrightarrow 2\mathrm{NaOH}(a q)+\mathrm{O}_{2}(g)$$

Equation (d) Completion

Given equation: $$\mathrm{N}_{2} \mathrm{O}_{3}(g)+\mathrm{H}_{2} \mathrm{O}(l) \longrightarrow?$$ Dinitrogen trioxide (N₂O₃) reacts with water (H₂O) to produce nitric acid (HNO₃): $$\mathrm{N}_{2} \mathrm{O}_{3}(g)+\mathrm{H}_{2} \mathrm{O}(l) \longrightarrow \mathrm{HNO}_{3}(a q)$$

Equation (d) Balancing

Balanced equation: $$\mathrm{N}_{2} \mathrm{O}_{3}(g)+\mathrm{H}_{2} \mathrm{O}(l) \longrightarrow 2\mathrm{HNO}_{3}(a q)$$

Equation (e) Completion

Given equation: $$\mathrm{KO}_{2}(s)+\mathrm{H}_{2} \mathrm{O}(l) \longrightarrow?$$ Potassium superoxide (KO₂) reacts with water (H₂O) to produce potassium hydroxide (KOH), oxygen (O₂) gas, and hydrogen peroxide (H₂O₂): $$\mathrm{KO}_{2}(s)+\mathrm{H}_{2} \mathrm{O}(l) \longrightarrow \mathrm{KOH}(a q)+\mathrm{O}_{2}(g)+\mathrm{H}_{2} \mathrm{O}_{2}(l)$$

Equation (e) Balancing

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

Equation (f) Completion

Given equation: $$\mathrm{NO}(g)+\mathrm{O}_{3}(g) \longrightarrow?$$ Nitric oxide (NO) reacts with ozone (O₃) to produce nitrogen dioxide (NO₂) and oxygen (O₂) gas: $$\mathrm{NO}(g)+\mathrm{O}_{3}(g) \longrightarrow \mathrm{NO}_{2}(g)+\mathrm{O}_{2}(g)$$

Equation (f) Balancing

The equation is already balanced.

Key concepts

Chemical Reaction Completion

Understanding the completion of chemical reactions is a crucial part of inorganic chemistry and involves predicting the products of a given set of reactants. A reaction is said to be complete when all reactants have been converted to products under the reaction conditions. When you encounter a problem like this in your homework, it's important to recall common reaction types such as synthesis, decomposition, single replacement, and double replacement reactions.

For instance, when calcium oxide reacts with water, through a synthesis reaction, it forms calcium hydroxide. Also, certain reactions may result in more complex product formation, such as the reaction of potassium superoxide with water producing both potassium hydroxide, oxygen gas, and hydrogen peroxide, showcasing a multi-step process. Understanding the nature of the reactants is key to predicting the correct products and thereby completing the chemical reaction. Always remember to check your predicted products against known chemical behavior and reaction patterns.

Stoichiometry

Stoichiometry is at the heart of chemical equations and is the quantitative relationship between reactants and products in a chemical reaction. It is based on the conservation of mass and the concept of the mole. Once the chemical reaction is completed, the next step is balancing the equation to ensure that the number of atoms for each element is the same on both sides of the equation.

When balancing chemical equations, such as those for aluminum oxide reacting with hydrogen ions or sodium peroxide with water, it’s essential to identify the mole ratio of the reactants and products, which follows from the stoichiometric coefficients in the balanced equation. For example, in the reaction involving aluminum oxide reacting with hydrogen ions, the balanced equation indicates that one mole of aluminum oxide reacts with six moles of hydrogen ions, yielding two moles of aluminum ions and three moles of water. The stoichiometry of a reaction helps to predict how much product will be formed from given amounts of reactants, which is essential not only for answering homework problems but also for practical applications in everyday chemical reactions and industrial processes.

Inorganic Chemistry

Inorganic chemistry is the branch of chemistry that deals with the properties and behavior of inorganic compounds, which typically include metals, minerals, and organometallic compounds. The reactions provided in the exercise are classic examples of inorganic reactions where simple compounds—often consisting of ionic bonds—undergo chemical changes. For instance, the oxide forms of elements such as in the reactions of calcium oxide (CaO), aluminum oxide (Al2O3), sodium peroxide (Na2O2), and potassium superoxide (KO2) with water show different products according to their chemical nature.

Inorganic reactions can involve a variety of reaction types, such as acid-base reactions, redox reactions, and precipitation reactions. Understanding the principles of inorganic chemistry, such as periodic table trends, oxidation states, and the nature of chemical bonds, is essential to solving the balance and completion of chemical equations. This branch of chemistry is essential not only for academic purposes but also has vast applications in fields like medicine, materials science, and environmental sciences, to name a few.