| Lesson Plan |
| Grade: |
Date: 25/02/2026 |
| Subject: Chemistry |
| Lesson Topic: Describe the preparation, separation and purification of soluble salts by reaction of an acid with: (a) an alkali by titration (b) excess metal (c) excess insoluble base (d) excess insoluble carbonate |
Learning Objective/s:
- Describe preparation methods for soluble salts via acid reaction with (a) alkali (titration), (b) excess metal, (c) excess insoluble base, and (d) excess insoluble carbonate.
- Explain the separation techniques used for each method.
- Apply purification steps to obtain pure crystalline salts.
- Predict observable signs (colour change, gas evolution) that indicate reaction completion.
- Evaluate the advantages and limitations of each preparation route.
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Materials Needed:
- Burette and stand
- Conical flasks
- Phenolphthalein indicator
- Dilute HCl and NaOH solutions
- Zinc granules, calcium carbonate, magnesium oxide (representative metals/bases)
- Filter paper and vacuum filtration set‑up
- Evaporating dish, water bath, drying oven or desiccator
- Safety goggles and lab coat
- Worksheets/summary table handout
- Projector for diagrams
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Introduction:
Begin with a quick demonstration of a colour change in a titration to prompt recall of acid‑base neutralisation. Review prior knowledge of strong acids, strong bases and the reactivity series. Explain that today students will learn how to prepare, separate and purify soluble salts using four different acid‑reaction routes, and that success will be shown by correctly completing the worksheet and describing each step.
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Lesson Structure:
- Do‑now (5’) – Students list known acid‑base reactions and write balanced equations.
- Mini‑lecture & diagram (10’) – Explain theory behind the four methods and display equations on the projector.
- Guided lab stations (30’) – Four stations rotating: (a) titration, (b) metal‑acid reaction, (c) insoluble base, (d) insoluble carbonate. Students perform preparation, note observations, and carry out separation.
- Purification demonstration (10’) – Teacher shows evaporation, crystallisation and filtration, linking to each station.
- Worksheet consolidation (10’) – Students complete a comparison table of reagents, separation and purification steps.
- Quick check (5’) – Exit ticket: one sentence describing the key purification step for any method.
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Conclusion:
Summarise how each method yields a soluble salt and the common purification sequence of evaporation, crystallisation and drying. Ask students to write an exit ticket stating which observation confirms the end‑point for the titration. Assign homework to research a real‑world application of one of the salts prepared.
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