Lesson Plan

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Lesson Plan
Grade: Date: 17/01/2026
Subject: Chemistry
Lesson Topic: Alkanes: properties, reactions, mechanisms
Learning Objective/s:
  • Describe the general formula, physical properties and isomerism of alkanes.
  • Explain the three‑step free‑radical halogenation mechanism (initiation, propagation, termination).
  • Predict the products of combustion and halogenation reactions for given alkanes.
  • Analyse boiling‑point trends in relation to molecular size and dispersion forces.
Materials Needed:
  • Projector and screen for slides
  • Whiteboard and markers
  • Handouts with alkane table and reaction equations
  • Molecular model kits
  • Safety goggles for combustion demo
  • Worksheet for mechanism practice
 Introduction:
Begin with a quick candle‑flame demonstration to capture interest, reminding students that hydrocarbons fuel everyday fires. Review the formula CₙH₂ₙ₊₂ and the concept of saturated hydrocarbons. State that by the end of the lesson they will be able to describe alkane properties, explain the free‑radical halogenation mechanism, and predict reaction outcomes.
Lesson Structure:
  1. Do‑now (5') – short quiz on hydrocarbon formulas and polarity.
  2. Mini‑lecture (10') – present physical/structural properties and boiling‑point trends using the alkane table.
  3. Interactive activity (10') – groups build alkane models and identify possible isomers.
  4. Demonstration (8') – safe combustion of a small alkane sample; discuss products and safety.
  5. Guided practice (12') – work through the free‑radical halogenation mechanism on the board; students fill in missing steps.
  6. Check for understanding (5') – exit ticket: write the overall halogenation equation for propane.
  7. Consolidation (5') – recap key points and answer remaining questions.
Conclusion:
Summarise that alkanes are non‑polar, their physical properties depend on molecular size, and their major reactions follow predictable mechanisms. Ask students to note one real‑world example of alkane use on an exit ticket. Assign homework to balance combustion and halogenation equations for C₄–C₆ alkanes.