TERM: 3RD TERM
WEEK: 6
CLASS: Junior Secondary School 2
AGE: 13 years
DURATION: 40 minutes each for 2 periods
DATE:
SUBJECT: Basic Science
TOPIC: Chemicals
SPECIFIC OBJECTIVES: At the end of the lesson, the learners should be able to
- ) Define chemicals
- ) State and explain the classification of chemicals
INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers, demonstration, story-telling, videos from source
INSTRUCTIONAL MATERIALS: Recommended Basic Science textbooks for Junior Secondary School 2
INSTRUCTIONAL PROCEDURES: PERIOD 1-2:
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PRESENTATION
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TEACHER’S ACTIVITY
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PUPIL’S ACTIVITY
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STEP 1
Review
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The teacher revises the previous lesson.
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Learners pay attention
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STEP 2
Introduction
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He defines chemicals
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Learners pay attention and participate
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STEP 3
Explanation
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He mentions and explains the classification of chemicals
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Learners pay attention and participate
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STEP 4
NOTE TAKING
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The teacher writes a short note on the board for the learners to copy
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The learners copy the note from the board
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NOTE
CHEMICALS
Chemicals are substances that consist of matter with a specific composition and structure. They are made up of atoms or molecules and can undergo chemical reactions. Chemicals can exist in various forms, including solids, liquids, and gases, and are found in both natural and synthetic environments. They are essential components of everyday materials and substances, including water, air, food, and medicines.
Classification of Chemicals
Chemicals can be classified in several ways, including by their composition, origin, or function. The most common classifications are as follows:
- Organic Chemicals
These are carbon-based compounds that usually contain carbon-hydrogen bonds. They are primarily derived from living organisms and can be synthesized in laboratories. Examples include hydrocarbons, sugars, proteins, and vitamins.
- Inorganic Chemicals
These do not primarily rely on carbon-hydrogen bonds. Inorganic chemicals include salts, metals, minerals, and acids. They are often found in nature and can also be synthesized. Examples include water, sodium chloride, and sulfuric acid.
- Acids
Chemicals that release hydrogen ions (H⁺) when dissolved in water. They have a pH lower than 7 and can be strong or weak acids depending on their ionization. Examples include hydrochloric acid (HCl) and acetic acid (CH₃COOH).
- Bases (Alkalis)
Chemicals that release hydroxide ions (OH⁻) when dissolved in water. They have a pH higher than 7 and can neutralize acids. Examples include sodium hydroxide (NaOH) and ammonia (NH₃).
- Salts
Ionic compounds formed when an acid reacts with a base. They consist of positively charged ions (cations) and negatively charged ions (anions). An example is sodium chloride (NaCl), which is formed from the neutralization of hydrochloric acid (HCl) and sodium hydroxide (NaOH).
- Elemental Chemicals
These are pure substances consisting of only one type of atom. They cannot be broken down into simpler substances by chemical means. Examples include hydrogen (H), oxygen (O), and gold (Au).
- Compounds
Chemicals formed from the chemical combination of two or more different elements in fixed ratios. Compounds can be broken down into simpler substances through chemical reactions. Examples include water (H₂O), carbon dioxide (CO₂), and methane (CH₄).
EVALUATION:
- What are the main differences between organic and inorganic chemicals? Provide examples of each.
- Explain the concept of acids and bases. How do their properties differ, and how are they classified?
- What is the role of salts in chemical reactions? Give two examples of salts and describe how they are formed.
- How are compounds different from elements? Illustrate with examples of both.
- Describe the process of chemical classification. Why is it important to categorize chemicals based on their composition and function?
CLASSWORK: As in evaluation
CONCLUSION: The teacher marks their books and commends them positively
