Lesson Plan

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Lesson Plan
Grade: Date: 17/01/2026
Subject: Chemistry
Lesson Topic: Deduce the structure or repeat unit of an addition polymer from a given alkene and vice versa
Learning Objective/s:
  • Describe the mechanism of addition polymerisation and how the polymer repeat unit is derived from an alkene monomer.
  • Apply a step‑by‑step procedure to convert a given alkene structure into its polymer repeat unit.
  • Deduce the original alkene monomer from a provided polymer repeat unit.
  • Analyse common addition polymers and identify their monomers and typical uses.
Materials Needed:
  • Projector or interactive whiteboard
  • Printed worksheet with alkene and polymer structures
  • Molecular model kits or online molecular visualiser
  • Markers and chart paper for group diagrams
  • Answer key for practice questions
 Introduction:
Begin with a quick video showing everyday plastic items and ask students what they are made of. Recall that most plastics are formed by addition polymerisation of simple alkenes. Today students will learn to translate between monomer and polymer structures and be able to predict one from the other. Success will be demonstrated by correctly completing the practice questions.
Lesson Structure:
  1. Do‑now (5’) – Students list three common plastic products and the polymers they think are involved; teacher checks responses.
  2. Mini‑lecture (10’) – Review addition polymerisation, double‑bond breaking, and formation of repeat units using the ethene example (projected diagram).
  3. Guided practice (15’) – Work through the “Alkene to polymer” procedure with vinyl acetate on the board; students fill in steps on the worksheet.
  4. Paired activity (15’) – Given polymer repeat units, students deduce the monomer using the reverse procedure; teacher circulates for questioning.
  5. Whole‑class review (10’) – Discuss answers to the practice questions, highlight common errors, and connect to the table of common polymers.
  6. Exit ticket (5’) – Each student writes one polymer‑monomer pair not covered today and the key step they used to derive it.
Conclusion:
Summarise that the repeat unit is a direct copy of the monomer after the double bond is opened, and that the reverse process restores the double bond. Collect exit tickets to assess understanding. For homework, assign students to choose an everyday plastic, research its monomer, and sketch the conversion.