| Lesson Plan |
| Grade: 9‑10 |
Date: 25/02/2026 |
| Subject: Chemistry |
| Lesson Topic: State that concentration can be measured in $\\mathrm{g} / \\mathrm{dm}^3$ or $\\mathrm{mol} / \\mathrm{dm}^3$ |
Learning Objective/s:
- State the two units used for expressing concentration (g dm⁻³ and mol dm⁻³).
- Convert between mass, moles and number of particles using the mole concept.
- Calculate mass and molar concentrations of a solution from given mass, volume or moles.
- Identify and correct common errors when determining concentration.
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Materials Needed:
- Projector or interactive whiteboard
- Printed handout or textbook section on concentration
- Worksheet with practice problems
- Calculator or classroom computers
- Beakers and sample solutions for a brief demonstration (optional)
- Whiteboard and markers
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Introduction:
Begin with the question “How would you describe how much solute is in a litre of soda?” to spark interest. Recall that students have already studied the mole and Avogadro’s constant. Explain that today they will learn how to express concentration using both mass‑based and mole‑based units and will be able to calculate each from given data.
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Lesson Structure:
- Do‑Now (5′): Quick recall quiz on the mole and Avogadro constant displayed on the board.
- Mini‑lecture (10′): Define concentration, introduce $\\mathrm{g\\,dm^{-3}}$ and $\\mathrm{mol\\,dm^{-3}}$ with formulas and the comparison table.
- Guided practice (12′): Work through the NaCl example together, projecting each calculation step and checking understanding.
- Independent practice (15′): Students complete worksheet problems (including the glucose question) while the teacher circulates to address misconceptions.
- Concept check (5′): Exit ticket – write the two concentration units and one common mistake to avoid.
- Summary & homework (3′): Recap key formulas and assign textbook exercises on converting between mass and molar concentration.
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Conclusion:
Recap that concentration can be expressed as mass per volume or moles per volume and that the appropriate formula depends on the information given. Collect the exit tickets to confirm understanding of the two units and a typical error. For homework, students complete the textbook questions on converting between mass and molar concentration.
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