Topic: Organic Chemistry – Polymers
Lesson 1: Introduction to Polymers and Addition Polymerization
| Section | Details |
|---|---|
| Objective | – Define polymers as large molecules formed from monomers.- Identify repeat units in addition polymers.- Deduce the structure or repeat unit of an addition polymer from a given alkene. |
| Activities | – Starter (5 mins): Show everyday polymer items (e.g., plastic bags, bottles) and ask: “What do these materials have in common?”- Main (25 mins): 1. Define polymers and monomers. 2. Explain addition polymerization: Alkenes act as monomers, forming polymers through breaking of double bonds. 3. Practice identifying repeat units in polymers like polyethene and PVC. 4. Deduce the repeat unit of a polymer from the given alkene (e.g., ethene → polyethene).- Plenary (10 mins): Students complete a worksheet identifying and drawing repeat units of given addition polymers. |
| Resources | Polymer samples, molecular models, worksheets. |
| Time | 40 minutes total: 5 mins (Starter) + 25 mins (Main) + 10 mins (Plenary). |
| Homework | Write the structural formula of the addition polymer formed from propene and chloroethene. |
| Assessment | Worksheet: Identify repeat units and deduce polymer structures. |
| Past Paper Practice | IGCSE Chemistry 0620/41/O/N/21 Q7(a) – Addition polymerization. |
Lesson 2: Condensation Polymers and Their Formation
| Section | Details |
|---|---|
| Objective | – Define condensation polymers.- Deduce the repeat unit of polyamides and polyesters from given monomers. |
| Activities | – Starter (5 mins): Show samples of nylon and PET and ask: “How are these materials different from addition polymers?”- Main (25 mins): 1. Explain condensation polymerization: Reaction between two monomers with the elimination of a small molecule (e.g., water). 2. Discuss formation of polyamides (e.g., nylon) from a dicarboxylic acid and a diamine. 3. Discuss formation of polyesters (e.g., PET) from a dicarboxylic acid and a diol. 4. Practice deducing repeat units from given monomers.- Plenary (10 mins): Students label a diagram showing the formation of nylon and PET. |
| Resources | Nylon and PET samples, molecular models, worksheets. |
| Time | 40 minutes total: 5 mins (Starter) + 25 mins (Main) + 10 mins (Plenary). |
| Homework | Draw and name the repeat units of nylon and PET. |
| Assessment | Worksheet: Deduce and draw repeat units of condensation polymers. |
| Past Paper Practice | IGCSE Chemistry 0620/41/M/J/20 Q7(b) – Condensation polymerization. |
Lesson 3: Properties and Environmental Impact of Plastics
| Section | Details |
|---|---|
| Objective | – Describe how properties of plastics affect their disposal.- Explain the environmental challenges caused by plastics. |
| Activities | – Starter (5 mins): Show images of plastic pollution and ask: “What problems do plastics cause in the environment?”- Main (25 mins): 1. Discuss properties of plastics (e.g., non-biodegradability, resistance to chemicals). 2. Explain challenges in disposal: – Landfill accumulation. – Ocean pollution. – Toxic gases from burning plastics. 3. Discuss potential solutions, such as recycling and biodegradable alternatives.- Plenary (10 mins): Students create a flowchart showing the life cycle of a plastic product and its environmental impact. |
| Resources | Images of plastic pollution, worksheets. |
| Time | 40 minutes total: 5 mins (Starter) + 25 mins (Main) + 10 mins (Plenary). |
| Homework | Write a short essay on how reducing plastic use can help the environment. |
| Assessment | Worksheet: Match plastic properties to their disposal challenges and propose solutions. |
| Past Paper Practice | IGCSE Chemistry 0620/41/O/N/20 Q7(c) – Environmental impact of plastics. |
Lesson 4: Proteins and Natural Polymers
| Section | Details |
|---|---|
| Objective | – Describe proteins as natural polyamides.- Draw the general structure of proteins. |
| Activities | – Starter (5 mins): Show a food label listing protein content and ask: “How is protein a polymer?”- Main (25 mins): 1. Explain proteins as natural polymers formed from amino acids. 2. Draw and explain the general structure of an amino acid and how peptide bonds form. 3. Discuss the importance of proteins in biological systems.- Plenary (10 mins): Students draw the general structure of a protein and label peptide bonds. |
| Resources | Protein structure diagrams, worksheets. |
| Time | 40 minutes total: 5 mins (Starter) + 25 mins (Main) + 10 mins (Plenary). |
| Homework | Draw the structure of a dipeptide formed from two amino acids. |
| Assessment | Worksheet: Label protein structures and explain their formation. |
| Past Paper Practice | IGCSE Chemistry 0620/41/O/N/21 Q7(d) – Proteins and natural polymers. |
Key Notes for Students:
- Polymers:
- Addition polymers: Formed from alkenes by breaking C=C bonds (e.g., polyethene).
- Condensation polymers: Formed by eliminating small molecules (e.g., water) during polymerization.
- Environmental Challenges of Plastics:
- Non-biodegradable, harmful to marine life, and toxic when burned.
- Proteins:
- Natural polyamides formed from amino acids.
- Contain peptide bonds linking amino acids.
Notes for Teachers:
- Use real-life examples of polymers and plastics to engage students.
- Highlight the importance of reducing plastic waste and promoting sustainability.
- Provide molecular models to illustrate polymerization processes.
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