Topic: Acids, Bases, and Salts – Oxides
Lesson 1: Amphoteric Oxides
| Section | Details |
|---|---|
| Objective | Describe amphoteric oxides as oxides that react with both acids and bases to produce a salt and water. |
| Activities | – Starter (5 mins): Ask: “Can a substance act as both an acid and a base?” Discuss student responses.- Main (25 mins): 1. Define amphoteric oxides and provide examples (e.g., Al2O3\text{Al}_2\text{O}_3 and ZnO\text{ZnO}). 2. Explain their reactions with acids and bases using equations (e.g., ZnO+2HCl→ZnCl2+H2O\text{ZnO} + 2\text{HCl} → \text{ZnCl}_2 + \text{H}_2\text{O}, ZnO+2NaOH→Na2ZnO2+H2O\text{ZnO} + 2\text{NaOH} → \text{Na}_2\text{ZnO}_2 + \text{H}_2\text{O}). 3. Demonstrate the reactions of amphoteric oxides with acids and alkalis, if possible.- Plenary (10 mins): Students summarize the concept by completing a table of examples and their reactions. |
| Resources | Samples of Al2O3\text{Al}_2\text{O}_3 and ZnO\text{ZnO}, acids, alkalis, reaction setups, worksheets. |
| Time | 40 minutes total: 5 mins (Starter) + 25 mins (Main) + 10 mins (Plenary). |
| Homework | Write balanced equations showing the reactions of Al2O3\text{Al}_2\text{O}_3 with HCl\text{HCl} and NaOH\text{NaOH}. |
| Assessment | Worksheet: Classify given oxides as amphoteric or not and justify the classification. |
| Past Paper Practice | IGCSE Chemistry 0620/41/M/J/19 Q3(b) – Reactions of amphoteric oxides with acids and bases. |
Lesson 2: Classification of Oxides
| Section | Details |
|---|---|
| Objective | Classify oxides as acidic, basic, or amphoteric based on their reactions and metallic/non-metallic character. |
| Activities | – Starter (5 mins): Show examples of common oxides (e.g., SO2\text{SO}_2, CaO\text{CaO}) and ask: “Are these acidic or basic? How do you know?”- Main (25 mins): 1. Define and explain the three types of oxides: – Acidic oxides: React with bases to form salt and water (e.g., SO2+2NaOH→Na2SO3+H2O\text{SO}_2 + 2\text{NaOH} → \text{Na}_2\text{SO}_3 + \text{H}_2\text{O}). – Basic oxides: React with acids to form salt and water (e.g., CuO+2HCl→CuCl2+H2O\text{CuO} + 2\text{HCl} → \text{CuCl}_2 + \text{H}_2\text{O}). – Amphoteric oxides: React with both acids and bases (e.g., Al2O3\text{Al}_2\text{O}_3, ZnO\text{ZnO}). 2. Relate oxides to metallic and non-metallic character. 3. Practice classification with examples.- Plenary (10 mins): Students complete a classification chart of oxides as acidic, basic, or amphoteric. |
| Resources | Examples of oxides (e.g., SO2\text{SO}_2, CO2\text{CO}_2, CuO\text{CuO}, CaO\text{CaO}), worksheets, reaction setups. |
| Time | 40 minutes total: 5 mins (Starter) + 25 mins (Main) + 10 mins (Plenary). |
| Homework | Write the reactions of SO2\text{SO}_2 and CO2\text{CO}_2 with alkalis, and CaO\text{CaO} and CuO\text{CuO} with acids. |
| Assessment | Worksheet: Classify oxides and write balanced equations for their reactions. |
| Past Paper Practice | IGCSE Chemistry 0620/41/O/N/21 Q3(c) – Classification of oxides as acidic, basic, or amphoteric. |
Key Notes for Students:
- Acidic Oxides:
- Formed by non-metals.
- React with bases to produce salt and water.
- Examples: SO2\text{SO}_2, CO2\text{CO}_2.
- Basic Oxides:
- Formed by metals.
- React with acids to produce salt and water.
- Examples: CuO\text{CuO}, CaO\text{CaO}.
- Amphoteric Oxides:
- Can react with both acids and bases.
- Examples: Al2O3\text{Al}_2\text{O}_3, ZnO\text{ZnO}.
Notes for Teachers:
- Ensure students understand the relationship between oxides and their metallic/non-metallic origins.
- Provide hands-on experiments, where possible, to demonstrate the reactions of oxides with acids and bases.
- Emphasize writing and balancing chemical equations for these reactions.
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