Class: Senior Secondary School 1 (SS1, SS 1, SSS1, SSS 1)
Term: 2nd Term
Week: 11
Age: 15 years
Duration: 45 minutes
Subject: Chemistry
Curriculum Theme: Chemistry
Previous Lesson: Acids, Bases And Salts: pH Scale, Deliquescent And Efflorescent and Hygroscopic.
Topic: ACIDS, BASES AND SALTS
Subject Matter: solubility of salts in water and other solvents, neutralization reaction, preparation of salts and solubility tests

Specific Objectives

By the end of the lesson, pupils should be able to:

Cognitive Domain:

Define solubility of salts.
Explain what a neutralization reaction is.
State different methods for preparing salts.

Affective Domain:

Observe and record colour changes during neutralization reactions.
Appreciate the importance of solubility tests in chemistry.

Psychomotor Domain:

Carry out a simple neutralization reaction using an indicator.
Prepare a simple salt from an acid-base reaction.
Test the solubility of given salts in water, ethanol, and acetone.

Collaborate effectively in practical activities.

Reference Materials

The following resources were used in planning this lesson:

9 Years Basic Education Curriculum for Chemistry.
State Unified Scheme of Work for Senior Secondary School Chemistry.
New School Chemistry for Senior Secondary Schools by Osei Yaw Ababio.

Instructional Materials

The teacher will teach this lesson with the aid of:

Distilled water
Acetone
Ethanol
Filter paper
Mortar and pestle
Litmus paper (red and blue)
Methyl orange indicator
Phenolphthalein indicator
Test tubes and rack
Beakers
Bunsen burner
Tripod stand and gauze
Hydrochloric acid (HCl)
Sodium hydroxide (NaOH)
Sodium chloride (NaCl)
Copper(II) sulphate (CuSO₄)
Chalkboard and marker

Rationale for the Lesson

This lesson helps pupils understand how salts behave in different liquids and how they are formed. Knowing about neutralization is important for everyday applications like treating indigestion and understanding soil chemistry.

Prerequisite/Previous Knowledge

Pupils should have prior knowledge of what acids, bases, and salts are, their general properties, and simple laboratory safety rules.

Lesson Content/Board Summary

ACIDS, BASES AND SALTS

1. Solubility of Salts in Water and Other Solvents

Solubility is the maximum amount of a solute that can dissolve in a given amount of solvent at a specific temperature to form a saturated solution.

Salts can have different solubilities in various solvents. Some salts are highly soluble in water, while others are sparingly soluble or insoluble. Solvents like ethanol and acetone can also dissolve certain salts, but their dissolving power differs from water.

The following are general solubility rules for salts in water:

All nitrates are soluble.
All chlorides are soluble except silver chloride, lead(II) chloride, and mercury(I) chloride.
All sulphates are soluble except barium sulphate, lead(II) sulphate, and calcium sulphate.
All sodium, potassium, and ammonium salts are soluble.
All carbonates are insoluble except sodium carbonate, potassium carbonate, and ammonium carbonate.
All oxides and hydroxides are insoluble except sodium, potassium, ammonium, and barium hydroxides.

2. Neutralization Reaction

Neutralization is a chemical reaction between an acid and a base that results in the formation of a salt and water. The pH of the resulting solution is usually close to 7 (neutral).

The general equation for neutralization is:

Acid + Base → Salt + Water

The following are common indicators used to detect the endpoint of a neutralization reaction:

Litmus paper: Turns red in acid, blue in base, and remains purple in neutral solution.
Methyl orange: Red in acid, yellow in base, orange at the endpoint.
Phenolphthalein: Colourless in acid, pink in base, and colourless at the endpoint.

3. Preparation of Salts

Salts can be prepared through various methods depending on whether they are soluble or insoluble.

The following are common methods for preparing salts:

Reaction of an acid with a base (neutralization): This method is used to prepare soluble salts. For example, HCl + NaOH → NaCl + H₂O.
Reaction of an acid with a metal: This method is used for metals above hydrogen in the reactivity series. For example, Zn + H₂SO₄ → ZnSO₄ + H₂.
Reaction of an acid with a metal carbonate: This method produces salt, water, and carbon dioxide. For example, CaCO₃ + 2HCl → CaCl₂ + H₂O + CO₂.
Precipitation (double decomposition): This method is used to prepare insoluble salts. Two soluble salt solutions are mixed to form an insoluble salt precipitate. For example, AgNO_3(aq) + NaCl_(aq) → AgCl_(s) + NaNO_3(aq).
Reaction of an acid with a metal oxide: For example, CuO + H₂SO₄ → CuSO₄ + H₂O.

4. Solubility Tests

To test the solubility of a salt, a small amount of the salt is added to a solvent (e.g., water, ethanol, acetone) in a test tube and stirred or shaken. Observations are made to determine if the salt dissolves.

The following are steps for conducting a solubility test:

Place a small amount of the salt into separate test tubes.
Add about 5 mL of the solvent (e.g., water) to one test tube.
Shake the test tube gently or stir with a glass rod.
Observe if the salt dissolves completely, partially, or not at all.
Repeat the process with other solvents like ethanol and acetone.

Teaching Methods/Instructional Techniques

Discussion, Lecture, Demonstration, Question and Answer, Visual Aids

Instructional Procedures

Step 1: Introduction

Time: 5 minutes
Teaching Skill: Set Induction
Teacher’s Activity: The teacher greets the pupils and reviews the previous lesson on general properties of acids and bases. The teacher then introduces the new topic, “Acids, Bases and Salts,” focusing on solubility, neutralization, and preparation of salts, by asking pupils what happens when sugar is added to water.
Pupils’ Activity: Pupils respond to questions and listen attentively to the introduction of the new topic.
Learning Point: Pupils are reminded of previous knowledge and prepared for the new lesson.

Step 2: Presentation of Solubility of Salts

Time: 10 minutes
Teaching Skill: Explanation/Demonstration
Teacher’s Activity: The teacher explains the concept of solubility and discusses general solubility rules for salts in water. The teacher then demonstrates the solubility of common salts (e.g., NaCl, CuSO₄) in water, ethanol, and acetone using the prepared materials.
Pupils’ Activity: Pupils observe the demonstration, take notes, and ask questions for clarification.
Learning Point: Pupils understand what solubility is and how salts behave in different solvents.

Step 3: Presentation of Neutralization Reaction

Time: 10 minutes
Teaching Skill: Demonstration/Explanation
Teacher’s Activity: The teacher defines neutralization reaction and writes the general equation on the board. The teacher then performs an experiment to illustrate neutralization using an acid (e.g., HCl) and a base (e.g., NaOH) with indicators like litmus paper, methyl orange, and phenolphthalein, showing the colour changes at the endpoint.
Pupils’ Activity: Pupils observe the experiment, record colour changes, and participate in a brief discussion.
Learning Point: Pupils grasp the concept of neutralization and the role of indicators.

Step 4: Presentation of Preparation of Salts

Time: 10 minutes
Teaching Skill: Lecture/Guidance
Teacher’s Activity: The teacher explains various methods for preparing salts, differentiating between methods for soluble and insoluble salts. The teacher guides pupils through the steps of preparing a simple salt (e.g., NaCl) from an acid-base reaction, emphasizing safety precautions.
Pupils’ Activity: Pupils listen to explanations, take notes on the methods, and ask questions about the preparation procedures.
Learning Point: Pupils learn the different methods for preparing salts and the practical steps involved.

Step 5: Practical Activity/Pupil Engagement

Time: 5 minutes
Teaching Skill: Practical/Supervision
Teacher’s Activity: The teacher distributes materials and supervises pupils as they carry out simple solubility tests on provided salts in different solvents or attempt a mini-neutralization reaction with indicators.
Pupils’ Activity: Pupils actively participate in the practical activity, following instructions and making observations.
Learning Point: Pupils gain hands-on experience in testing solubility and performing neutralization.

Step 6: Class Discussion and Recap

Time: 5 minutes
Teaching Skill: Questioning/Facilitation
Teacher’s Activity: The teacher facilitates a brief discussion to review the main points covered. The teacher asks pupils to recap the definition of neutralization and one method of preparing salts.
Pupils’ Activity: Pupils contribute to the discussion and recap key concepts.
Learning Point: Pupils consolidate their understanding of the lesson content.

Step 7: Evaluation/Review

Time: 5 minutes

Teaching Skill: Questioning/Assessment

Teacher’s Activity: The teacher evaluates the learning by asking the following questions:

Define solubility of salts.
What is a neutralization reaction?
State two methods for preparing salts.
Mention two indicators used in neutralization and their colour changes in acid and base.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 8: Conclusion

Time: 2 minutes
Teaching Skill: Summarization/Assignment
Teacher’s Activity: The teacher summarizes the lesson by reiterating the importance of understanding solubility, neutralization, and salt preparation. The teacher then gives homework: “List three examples of soluble salts and three examples of insoluble salts, stating their uses.”
Pupils’ Activity: Pupils listen to the summary and copy down the homework.
Learning Point: Pupils have a clear understanding of the lesson and are given a task to reinforce learning.

Lesson Keywords

Solubility – The ability of a substance to dissolve in a solvent.
Neutralization – A reaction between an acid and a base forming salt and water.
Indicator – A substance that shows colour change in acidic or basic solutions.
Salt – An ionic compound formed from the reaction of an acid and a base.
Solvent – A substance that dissolves a solute, forming a solution.

Differentiation

The teacher will provide additional support for struggling pupils through simplified explanations and one-on-one guidance during practical sessions. Advanced pupils will be encouraged to research more complex methods of salt preparation or investigate factors affecting solubility.

Note for teachers using this lesson plan

Ensure all laboratory safety rules are strictly followed, especially when handling acids, bases, and organic solvents like acetone and ethanol. Adequate ventilation should be provided during experiments. Prepare all reagents and materials in advance to ensure smooth practical sessions.