Chapter 455: Balance The Following Chemical Equations

Chapter 455 Balance The Following Chemical Equations

Balance the following chemical equations and predict whether each substance is soluble or insoluble in water. Additionally, describe how hydrofluoric acid (HF) acts when added to water, including the nature of particles before and after the reaction, the reversible reactions involved, classify chemical formulas, categorize substances based on acidity and basicity, write neutralization equations, analyze oxidation-reduction processes, and determine oxidation states and reaction types.

Sample Paper For Above instruction

Introduction

The comprehensive understanding of chemical equations, solubility, acid-base reactions, and redox processes is fundamental to chemistry. This paper systematically addresses the tasks of balancing chemical equations, predicting solubility, understanding acid behavior, classifying chemical compounds, writing neutralization reactions, analyzing redox reactions, and determining oxidation states in battery chemistry. Each section combines theoretical principles with practical examples to elucidate key concepts.

Balancing Chemical Equations and Solubility Predictions

Balancing chemical equations requires ensuring the number of atoms for each element is equal on both sides of the reaction. For example, consider the unbalanced reaction:

\[ \text{C}_2\text{H}_6 + \text{O}_2 \rightarrow \text{CO}_2 + \text{H}_2\text{O} \]

Balancing involves adjusting coefficients:

\[ \text{C}_2\text{H}_6 + 3\text{O}_2 \rightarrow 2\text{CO}_2 + 3\text{H}_2\text{O} \]

Predicting solubility involves referencing solubility rules. Copper(II) hydroxide \( \text{Cu(OH)}_2 \) is generally insoluble in water. Silver carbonate \( \text{Ag}_2\text{CO}_3 \) is also insoluble. Conversely, substances like sodium hydroxide are soluble.

The chemical equations must be balanced accordingly, considering the states of products and reactants.

Behavior of Hydrofluoric Acid in Water

Hydrofluoric acid (HF) is a weak monoprotic acid that reacts with water through a reversible reaction:

\[ \text{HF} + \text{H}_2\text{O} \leftrightarrows \text{H}_3\text{O}^+ + \text{F}^- \]

Before reacting, the particles in solution include intact HF molecules and water molecules. After the reaction, the particles include hydronium ions \( \text{H}_3\text{O}^+ \) and fluoride ions \( \text{F}^- \).

The forward reaction involves HF donating a proton (acting as an acid) to water, while the reverse reaction involves fluoride ions accepting a proton, reforming HF. This equilibrium influences the acidity of the solution.

Classification of Chemical Formulas

Classifying formulas involves recognizing patterns:

- Example a: HI(aq) is a binary acid (hydroiodic acid).

- Example b: \( \text{Na}_2\text{CO}_3 \) is an ionic compound with polyatomic ions.

- Example c: \( \text{CCl}_4 \) is a binary covalent compound.

- Example d: \( \text{H}_2\text{SO}_4 \) is a diprotic oxyacid.

- Example e: \( \text{NH}_4\text{NO}_3 \) is an ionic compound with polyatomic ions.

- Example f: \( \text{HNO}_3 \) is a strong acid (nitrate acid).

- Example g: \( \text{P}_4\text{O}_{10} \) is a binary covalent compound.

Classification of Acids and Bases

Based on the Arrhenius definition:

- Weak acids: Nitrous acid \( \text{HNO}_2 \)

- Strong acids: Nitric acid \( \text{HNO}_3 \)

- Weak bases: Ammonia \( \text{NH}_3 \)

- Strong bases: Lithium hydroxide \( \text{LiOH} \)

- Phosphorous acid \( \text{H}_3\text{PO}_3 \) is a weak acid.

Neutralization Reactions

Neutralization occurs when acids and bases react to form water and salts:

- Example:

\[ \text{LiOH}(aq) + \text{HCl}(aq) \rightarrow \text{LiCl}(aq) + \text{H}_2\text{O}(l) \]

- Since the specifics are not provided for other reactions, similar principles apply: acids react with hydroxide ions, and bases react with hydrogen ions, leading to neutral products.

Conjugate Base of Hexanoic Acid and its Reaction

Hexanoic acid \( \text{C}_5\text{H}_{11}\text{COOH} \), reacts with water:

\[ \text{C}_5\text{H}_{11}\text{COOH} + \text{H}_2\text{O} \leftrightarrows \text{C}_5\text{H}_{11}\text{COO}^- + \text{H}_3\text{O}^+ \]

The conjugate base is hexanoate \( \text{C}_5\text{H}_{11}\text{COO}^- \).

The forward reaction involves the acid donating a proton (acting as a Brønsted-Lowry acid), and water acts as a base accepting it, forming hydronium ions.

Redox Reactions and Electron Transfer

In reactions such as calcium reacting with other elements, electrons are often completely transferred from one atom to another, characteristic of oxidation-reduction reactions. Partial transfer indicates a covalent interaction, whereas complete transfer signifies a redox process.

The oxidation of iodine by chlorine involves the following half-reactions:

- Oxidation: \( \text{I}^- \rightarrow \text{I}_2 + 2e^- \)

- Reduction: \( \text{Cl}_2 + 2e^- \rightarrow 2\text{Cl}^- \)

Oxidation-Reduction in Battery Chemistry

In nickel-cadmium batteries, the key reaction involves:

\[ \text{Cd}(s) + 2\text{NiO(OH)}(s) \rightarrow \text{CdO}(s) + 2\text{Ni}(s) \]

Oxidation numbers:

- Cadmium (Cd): from 0 to +2 (oxidized)

- Nickel (Ni): from +3 in NiO(OH) to 0 (reduced)

The oxidizing agent is NiO(OH), which accepts electrons, while cadmium acts as the reducing agent by donating electrons.

Conclusion

This detailed exploration underscores the importance of balancing chemical equations, understanding solubility, acid-base behavior, redox processes, and oxidation states. Mastery of these concepts facilitates a deeper comprehension of chemical reactions, both in academic contexts and practical applications like batteries and industrial processes.

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