Lesson Plan

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Lesson Plan
Grade: Date: 17/01/2026
Subject: Chemistry
Lesson Topic: Interpret reaction pathway diagrams showing exothermic and endothermic reactions
Learning Objective/s:
  • Describe the key components of an energy‑profile (reaction pathway) diagram.
  • Interpret a diagram to calculate activation energy (Eₐ) and the sign of ΔH.
  • Classify a reaction as exothermic or endothermic based on the diagram.
  • Explain how a catalyst alters the activation‑energy peak.
Materials Needed:
  • Projector or interactive whiteboard
  • Printed energy‑profile worksheets
  • Sample reaction pathway diagrams (exothermic & endothermic)
  • Scientific calculators
  • Sticky notes or response cards
  • Markers and whiteboard
 Introduction:
Begin with a quick discussion of everyday heat phenomena (e.g., hand‑warmers vs. ice packs) to hook interest. Prompt students to recall that chemical reactions involve energy changes and that ΔH indicates the direction of heat flow. State that by the end of the lesson they will reliably read energy‑profile diagrams and determine whether a reaction releases or absorbs heat.
Lesson Structure:
  1. Do‑now (5'): Think‑pair‑share examples of exothermic and endothermic processes.
  2. Mini‑lecture with slides (10'): Introduce diagram components – reactants, products, transition state, ΔH, Eₐ.
  3. Guided walkthrough (8'): Teacher models interpreting a sample exothermic diagram, calculating Eₐ and ΔH.
  4. Independent practice (12'): Students complete a worksheet with two diagrams, calculate values, and label the reaction type.
  5. Catalyst discussion (5'): Whole‑class demo showing how a catalyst lowers the peak height.
  6. Check for understanding (5'): Exit‑ticket – one sentence summarising how to tell exothermic from endothermic on a diagram.
Conclusion:
Recap the five diagram features and how they reveal ΔH and Eₐ. Collect exit tickets to gauge mastery and assign homework: find a real‑world reaction, sketch its energy profile, and state the sign of ΔH. This reinforces interpretation skills and connects theory to everyday chemistry.