Question

Complete and balance the equations for the following acid-base reactions. Name the reactants and products. (a) \(\mathrm{CH}_{3} \mathrm{CO}_{2} \mathrm{H}(\mathrm{aq})+\mathrm{Mg}(\mathrm{OH})_{2}(\mathrm{s}) \rightarrow\) (b) \(\mathrm{HClO}_{4}(\mathrm{aq})+\mathrm{NH}_{3}(\mathrm{aq}) \rightarrow\)

Short answer

(a) Balanced as: 2 CH₃CO₂H + Mg(OH)₂ → (CH₃CO₂)₂Mg + 2 H₂O. (b) Balanced as: HClO₄ + NH₃ → NH₄ClO₄.

Step-by-step solution

Write Down the Given Reactions

The given reactions are: (a) \( \mathrm{CH}_3 \mathrm{CO}_2 \mathrm{H}(\mathrm{aq})+\mathrm{Mg}(\mathrm{OH})_2(\mathrm{s}) \rightarrow \) (b) \( \mathrm{HClO}_4(\mathrm{aq})+\mathrm{NH}_3(\mathrm{aq}) \rightarrow \). These need to be completed and balanced.

Identify the Reactants and Potential Products for Reaction (a)

In reaction (a), the reactants are acetic acid \(\mathrm{CH}_3 \mathrm{CO}_2 \mathrm{H}\) and magnesium hydroxide \(\mathrm{Mg}(\mathrm{OH})_2\). This is an acid-base reaction, likely producing magnesium acetate \((\mathrm{CH}_3 \mathrm{CO}_2)_2 \mathrm{Mg}\) and water \(\mathrm{H}_2\mathrm{O}\) as products.

Balance Reaction (a)

The unbalanced reaction is: \( \mathrm{CH}_3 \mathrm{CO}_2 \mathrm{H}(\mathrm{aq}) + \mathrm{Mg}(\mathrm{OH})_2(\mathrm{s}) \rightarrow (\mathrm{CH}_3 \mathrm{CO}_2)_2 \mathrm{Mg}(\mathrm{aq}) + \mathrm{H_2O}(\mathrm{l}) \). Balancing it: Two moles of acetic acid are needed to react with one mole of magnesium hydroxide: \( 2 \mathrm{CH}_3 \mathrm{CO}_2 \mathrm{H}(\mathrm{aq}) + \mathrm{Mg}(\mathrm{OH})_2(\mathrm{s}) \rightarrow (\mathrm{CH}_3 \mathrm{CO}_2)_2 \mathrm{Mg}(\mathrm{aq}) + 2 \mathrm{H_2O}(\mathrm{l}) \).

Identify the Reactants and Products for Reaction (b)

In reaction (b), the reactants are perchloric acid \(\mathrm{HClO}_4\) and ammonia \(\mathrm{NH}_3\). This is an acid-base reaction, producing ammonium perchlorate \(\mathrm{NH}_4\mathrm{ClO}_4\).

Balance Reaction (b)

The reaction is: \( \mathrm{HClO}_4(\mathrm{aq}) + \mathrm{NH}_3(\mathrm{aq}) \rightarrow \mathrm{NH}_4\mathrm{ClO}_4(\mathrm{aq}) \). This equation is already balanced, as both sides have equal numbers of each type of atom.

Name the Reactants and Products

- For reaction (a): - Reactants: Acetic acid (\(\mathrm{CH}_3 \mathrm{CO}_2 \mathrm{H}\)), Magnesium hydroxide (\(\mathrm{Mg}(\mathrm{OH})_2\)) - Products: Magnesium acetate (\((\mathrm{CH}_3 \mathrm{CO}_2)_2 \mathrm{Mg}\)), Water (\(\mathrm{H}_2\mathrm{O}\)) - For reaction (b): - Reactants: Perchloric acid (\(\mathrm{HClO}_4\)), Ammonia (\(\mathrm{NH}_3\)) - Product: Ammonium perchlorate (\(\mathrm{NH}_4\mathrm{ClO}_4\))

Key concepts

Chemical Equations

Chemical equations provide a concise way to represent chemical reactions using chemical formulas instead of words. In an acid-base reaction, acids react with bases to produce salts and water. A chemical equation shows both the substances entering the reaction, called reactants, and the new substances formed, known as products. It's important to note the physical states of each compound, often represented by symbols such as (aq) for aqueous or (s) for solid.
The chemical equations for acid-base reactions generally follow the pattern: \(\text{Acid} + \text{Base} \rightarrow \text{Salt} + \text{Water}\). In exercise (a), acetic acid \((\mathrm{CH}_3 \mathrm{CO}_2 \mathrm{H})\) reacts with magnesium hydroxide \((\mathrm{Mg(OH)_2})\) to form magnesium acetate \((\mathrm{(CH}_3 \mathrm{CO}_2)_2 \mathrm{Mg})\) and water \((\mathrm{H}_2 \mathrm{O})\). In exercise (b), perchloric acid \((\mathrm{HClO}_4)\) reacts with ammonia \((\mathrm{NH}_3)\) to produce ammonium perchlorate \((\mathrm{NH}_4\mathrm{ClO}_4})\).
Understanding chemical equations helps chemists convey complex information clearly, making reactions easier to study and analyze.

Balancing Reactions

Balancing chemical equations is a critical skill in chemistry. It ensures that we have the same number of each type of atom on both the reactants and products sides of the equation, obeying the conservation of mass. In reaction (a), the equation starts as \(\mathrm{CH}_3 \mathrm{CO}_2 \mathrm{H} + \mathrm{Mg(OH)_2} \rightarrow (\mathrm{CH}_3 \mathrm{CO}_2)_2 \mathrm{Mg} + \mathrm{H_2O}\). By balancing, we find that it requires two acetic acid molecules to react with one magnesium hydroxide to form one magnesium acetate and two water molecules, represented as:

• \(2 \mathrm{CH}_3 \mathrm{CO}_2 \mathrm{H} + \mathrm{Mg(OH)_2} \rightarrow (\mathrm{CH}_3 \mathrm{CO}_2)_2 \mathrm{Mg} + 2 \mathrm{H_2O}\)

Balancing reaction (b) is simpler since it naturally balances as:

• \(\mathrm{HClO}_4 + \mathrm{NH}_3 \rightarrow \mathrm{NH}_4\mathrm{ClO}_4\)

No extra steps are needed since there are equal numbers of each type of atom before and after the reaction. Balancing not only respects the law of conservation of mass but also aids in calculating reactants' and products' amounts in more practical applications.

Naming Chemical Compounds

Naming chemical compounds involves using a systematic method that conveys information about the chemical composition and structure. The names often provide clues about the types of atoms present and how they are bonded together. In the context of acid-base reactions, knowing how to name compounds correctly is crucial. For example:

• Acids: Acetic acid \((\mathrm{CH}_3 \mathrm{CO}_2 \mathrm{H})\) is named by its organic origin, while perchloric acid \((\mathrm{HClO}_4)\) follows the pattern of oxoacids, utilizing the root of the polyatomic ion (chlorate) with the prefix "per-" and suffix "-ic".
• Bases: Magnesium hydroxide \((\mathrm{Mg(OH)_2})\) is named by stating the metal followed by the polyatomic ion hydroxide.
• Salts and Ions: The naming of salts includes identifying the positive metal ion and the negative nonmetal or polyatomic ion; hence, magnesium acetate \((\mathrm{(CH}_3 \mathrm{CO}_2)_2 \mathrm{Mg})\) and ammonium perchlorate \((\mathrm{NH}_4\mathrm{ClO}_4})\) are named respectively with metal/cation followed by the anion.

Understanding how to name chemical compounds properly aids communication and ensures clarity in both academic and laboratory settings.