| Lesson Plan |
| Grade: |
Date: 25/02/2026 |
| Subject: Chemistry |
| Lesson Topic: Define activation energy, $E_{a}$, as the minimum energy that colliding particles must have to react |
Learning Objective/s:
- Describe activation energy and its role in reaction rates.
- Interpret energy‑profile diagrams to identify activation energy, reactants, products, and $\Delta H$.
- Explain how temperature, particle size, and catalysts affect activation energy.
- Apply the Arrhenius equation to evaluate the effect of activation energy on reaction rate.
- Solve a Boltzmann‑distribution calculation to estimate the fraction of molecules with sufficient energy.
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Materials Needed:
- Projector or interactive whiteboard
- Slide deck with energy‑profile diagrams
- Printed worksheet with calculation problems
- Molecular model kits (optional)
- Calculator or computers with spreadsheet software
- Catalyst samples (e.g., powdered copper) for demonstration (optional)
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Introduction:
Begin with a quick demonstration: drop a marble into a shallow bowl versus a deep bowl to illustrate the concept of a barrier. Ask students to recall how temperature influences reaction speed from previous lessons. Explain that today they will define activation energy, read energy‑profile diagrams, and learn how catalysts lower this barrier. Success will be measured by their ability to interpret diagrams and perform a simple calculation.
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Lesson Structure:
- Do‑now (5'): Students answer a short prompt on why some reactions are slow at room temperature.
- Mini‑lecture (10'): Define activation energy, introduce the Arrhenius equation, and display energy‑profile diagrams.
- Guided practice (12'): Work through the Boltzmann fraction example together; students complete the worksheet.
- Interactive activity (10'): Small groups compare exothermic and endothermic diagrams, identify $E_{a}$, and discuss catalyst effects.
- Quick quiz (5'): Exit‑ticket with two questions on the definition of $E_{a}$ and how catalysts influence it.
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Conclusion:
Summarise that activation energy is the energy barrier that must be overcome for a reaction to proceed and that catalysts provide an alternative pathway with a lower barrier. Prompt students to write one real‑world example of a catalyst on their exit ticket. Assign homework: complete a worksheet converting $\Delta H$ values into energy‑profile sketches; collect exit tickets to gauge understanding.
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