Second Term Chemistry revision for SS 1

Class: SS 1
Term: Second Term
Week: 11
Age: 15 years
Duration: 60 minutes
Subject: Chemistry
Curriculum Theme: Revision
Focal competence: Integration of the term’s curriculum competencies
Key competencies/values: Critical Thinking; Communication
Skills:

• Curriculum skills covered in Weeks 1-10

Previous Lesson: Factors affecting equilibrium and Industrial applications
Topic: Revision and Consolidation
Subject Matter: core term topics, taught skills, common misconceptions, revision exercises

Specific Objectives

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

Cognitive Domain

• recall the key concepts taught during the term;
• apply the term’s knowledge in solving problems.

Affective Domain

• appreciate the importance of revision for academic success;
• participate actively in revision exercises and discussions.

Psychomotor Domain

• apply learned skills in written and oral tasks;
• demonstrate understanding through practical problem-solving.

Social Domain

• collaborate effectively with peers during group revision activities.

Reference Materials

The following resources were used in planning this lesson:

• 2025 New Revised Senior Secondary Education Curriculum (SSEC)
• Relevant State Unified Scheme of Work
• A suitable Chemistry textbook for SS 1
• The HeadTeacher Scheme of work For The New Revised Senior Secondary Education Curriculum (SSEC)

Instructional Materials

The teacher will teach this lesson with the aid of:

• Class notes and approved textbooks
• Past questions/revision exercises
• Whiteboard/Chalkboard and markers/chalk

Rationale for the Lesson

This lesson is essential for consolidating students’ understanding of all Chemistry topics covered during the Second Term. It provides an opportunity to review difficult concepts, address misconceptions, and practice applying knowledge and skills, thereby preparing students for examinations and future learning.

Prerequisite/Previous Knowledge

Students should have a foundational understanding of all Chemistry topics taught from Week 1 to Week 10 of the Second Term.

Lesson Content/Board Summary

Revision and Consolidation

Review of Key Concepts: Acids, Bases, and Salts

Acids: Substances that produce hydrogen ions ((H^+)) when dissolved in water. They turn blue litmus paper red and have a sour taste. Examples include hydrochloric acid ((HCl)), sulphuric acid ((H_2SO_4)), and ethanoic acid ((CH_3COOH)).

1. Properties of Acids:
   1. Sour taste (not to be tested in the lab).
   2. Corrosive nature.
   3. Turn blue litmus red.
   4. React with metals above hydrogen in the activity series to produce hydrogen gas.
   5. React with bases to form salt and water (neutralisation).
   6. React with carbonates and bicarbonates to produce carbon dioxide gas.
2. Types of Acids:
   1. Strong Acids: Ionise completely in water (e.g., (HCl), (H_2SO_4), (HNO_3)).
   2. Weak Acids: Ionise partially in water (e.g., (CH_3COOH), (H_2CO_3)).

Bases: Substances that react with acids to form salt and water only. They turn red litmus paper blue and have a bitter taste. Soluble bases are called alkalis.

1. Properties of Bases/Alkalis:
   1. Bitter taste (not to be tested in the lab).
   2. Soapy feel.
   3. Turn red litmus blue.
   4. React with acids to form salt and water.
   5. Alkalis react with ammonium salts to produce ammonia gas.
2. Types of Bases:
   1. Strong Bases/Alkalis: Ionise completely in water (e.g., (NaOH), (KOH)).
   2. Weak Bases: Ionise partially in water (e.g., (NH_4OH), (Mg(OH)_2)).

Salts: Ionic compounds formed when the hydrogen ion of an acid is replaced by a metal ion or ammonium ion. They are typically formed from the reaction of an acid with a base, metal, or carbonate.

1. Types of Salts:
   1. Normal Salts: Formed when all replaceable hydrogen ions of an acid are completely replaced by a metal or ammonium ion (e.g., (NaCl), (K_2SO_4)).
   2. Acid Salts: Formed when only part of the replaceable hydrogen ions of a polybasic acid are replaced (e.g., (NaHCO_3), (NaHSO_4)).
   3. Basic Salts: Formed when a base contains more than one hydroxyl group and only part of it is replaced by an acid radical (e.g., (Zn(OH)Cl)).
   4. Double Salts: Formed when two simple salts crystallise together from a single solution (e.g., Potash alum, (K_2SO_4 cdot Al_2(SO_4)_3 cdot 24H_2O)).
   5. Complex Salts: Contain a complex ion (e.g., potassium hexacyanoferrate(II), (K_4[Fe(CN)_6])).
2. Preparation of Salts:
   1. Soluble Salts:
      1. Acid + Active Metal (e.g., (Zn + H_2SO_4 rightarrow ZnSO_4 + H_2)).
      2. Acid + Base/Alkali (Neutralisation) (e.g., (HCl + NaOH rightarrow NaCl + H_2O)).
      3. Acid + Carbonate (e.g., (HNO_3 + CaCO_3 rightarrow Ca(NO_3)_2 + H_2O + CO_2)).
   2. Insoluble Salts:
      1. Precipitation (Double decomposition) (e.g., (AgNO_3(aq) + NaCl(aq) rightarrow AgCl(s) + NaNO_3(aq))).

Review of Key Concepts: Water

Water: A chemical compound with the chemical formula (H_2O). It is essential for all known forms of life.

1. Sources of Water:
   1. Rain water (purest natural form).
   2. Surface water (rivers, lakes, oceans).
   3. Ground water (wells, boreholes, springs).
2. Properties of Water:
   1. Colourless, odourless, tasteless liquid.
   2. Boiling point: (100^circ C), Freezing point: (0^circ C).
   3. Density: (1 g/cm^3) at (4^circ C).
   4. Universal solvent.
   5. Amphoteric nature (can act as both an acid and a base).
3. Hardness of Water: The presence of dissolved mineral salts (calcium and magnesium ions) in water.
1. Temporary Hardness: Caused by dissolved calcium bicarbonate ((Ca(HCO_3)_2)) and magnesium bicarbonate ((Mg(HCO_3)_2)). Can be removed by boiling.
2. Permanent Hardness: Caused by dissolved calcium sulphate ((CaSO_4)), magnesium sulphate ((MgSO_4)), calcium chloride ((CaCl_2)), and magnesium chloride ((MgCl_2)). Cannot be removed by boiling.
4. Methods of Removing Hardness:
   1. Temporary Hardness:
      1. Boiling (precipitates carbonates).
      2. Addition of slaked lime (Clark’s method).
   2. Permanent Hardness:
      1. Addition of washing soda (sodium carbonate).
      2. Ion-exchange method (using resins or permutit).
5. Water Treatment: The process of making water safe for drinking (potable).
1. Stages of Water Treatment:
   1. Screening: Removal of large debris.
   2. Aeration: Introduction of air to oxidise impurities.
   3. Coagulation/Flocculation: Addition of chemicals like alum to clump small particles together.
   4. Sedimentation: Allowing heavy particles to settle.
   5. Filtration: Passing water through sand beds to remove suspended particles.
   6. Chlorination: Addition of chlorine to kill germs.
   7. Fluoridation: Addition of fluoride to prevent tooth decay (optional).

Teaching Methods/Instructional Techniques

Discussion, Question and Answer, Explanation, Guided Practice, Problem Solving, Review of Worked Examples.

Instructional Procedures

Step 1: Introduction

Time: 5 minutes

Teaching Skill: Activating Prior Knowledge

Teacher’s Activity: The teacher welcomes students, reminds them that it’s a revision week, and briefly explains the importance of reviewing all topics covered during the term. The teacher asks students to mention some key topics they found challenging in the term.

Pupils’ Activity: Pupils respond by mentioning topics they recall or found difficult. They listen attentively to the teacher’s introduction.

Learning Point: Importance of revision

Step 2: Review of Acids, Bases, and Salts

Time: 15 minutes

Teaching Skill: Explanation/Questioning

Teacher’s Activity: The teacher leads a discussion on Acids, Bases, and Salts, highlighting their definitions, properties, types, and methods of preparation. The teacher uses focused questions to prompt recall and clarify misconceptions, referring to the Board Summary.

Pupils’ Activity: Pupils actively participate in the discussion, answer questions, and ask for clarification on concepts related to Acids, Bases, and Salts.

Learning Point: Acids, Bases, Salts concepts

Step 3: Worked Examples on Acids, Bases, and Salts

Time: 10 minutes

Teaching Skill: Demonstration/Problem Solving

Teacher’s Activity: The teacher presents and solves a few past questions or revision exercises related to Acids, Bases, and Salts on the board, demonstrating how to apply the learned concepts (e.g., balancing neutralisation reactions, identifying salt types).

Pupils’ Activity: Pupils observe the worked examples, ask questions about the steps, and attempt to solve similar problems mentally or on scrap paper.

Learning Point: Application of concepts

Step 4: Review of Water

Time: 10 minutes

Teaching Skill: Explanation/Discussion

Teacher’s Activity: The teacher guides a review of the topic “Water,” covering its sources, properties, types of hardness, methods of removing hardness, and the stages of water treatment. The teacher encourages students to recall details from their notes.

Pupils’ Activity: Pupils recall and discuss the various aspects of water, contributing to the review and asking questions where they are unsure.

Learning Point: Water properties and treatment

Step 5: Revision Exercises on Water

Time: 10 minutes

Teaching Skill: Guided Practice

Teacher’s Activity: The teacher distributes short revision exercises or past questions focused on “Water” (e.g., identifying types of hardness, listing water treatment stages). The teacher monitors students’ work and provides immediate feedback.

Pupils’ Activity: Pupils work individually or in pairs to complete the revision exercises, applying their knowledge of water-related concepts.

Learning Point: Water concepts application

Step 6: Addressing Common Misconceptions

Time: 5 minutes

Teaching Skill: Clarification/Correction

Teacher’s Activity: Based on observations from previous lessons and the current revision, the teacher addresses common misconceptions related to any of the reviewed topics (e.g., difference between strong/weak acids, temporary/permanent hardness). The teacher provides clear explanations and examples.

Pupils’ Activity: Pupils listen to the clarifications, ask further questions, and correct any misunderstandings in their notes.

Learning Point: Clarifying misconceptions

Step 7: Evaluation/Review

Time: 5 minutes

Teaching Skill: Questioning/Assessment

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

1. State two properties of acids and two properties of bases.
2. Differentiate between temporary and permanent hardness of water.
3. List three stages involved in the treatment of water for drinking.
4. Give an example of a normal salt and an acid salt.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Recall of key concepts

Step 8: Conclusion

Time: 5 minutes

Teaching Skill: Consolidation

Teacher’s Activity: The teacher summarises the main points of the revision, encouraging students to continue studying their notes and practice with more past questions. The teacher reminds them of the upcoming examinations.

Pupils’ Activity: Pupils listen and prepare for the end of the lesson, asking any final questions.

Learning Point: Term’s concepts consolidated

Lesson Keywords

• Acids – Substances that produce hydrogen ions in water.
• Bases – Substances that react with acids to form salt and water.
• Salts – Ionic compounds formed from the replacement of hydrogen ions in an acid.
• Hardness – Presence of dissolved mineral salts in water.
• Potable water – Water safe for drinking.
• Neutralisation – Reaction between an acid and a base.

Differentiation

For students who are struggling, provide simpler revision questions and allow for peer tutoring. Encourage advanced learners to attempt more complex problem-solving questions from past examinations and to explain concepts to their peers.

Suggested Lesson Videos

For further understanding, search on YouTube for: “SS1 Chemistry Second Term Revision” or “Acids Bases Salts Water Treatment Chemistry SS1”.