Year 9 Science · Unit 2 · Lesson 20
Challenge Worksheet
Learning Goals
Find the mistake
A student wrote this answer
"The solution to plastic pollution is simple: replace all plastics with biodegradable materials. Once we do this, microplastics will disappear from the ocean because new materials will break down. Metals and ceramics are better than plastics for all applications because they're harder and last longer. The energy transition just requires replacing fossil fuels with solar, and then chemistry problems are all solved."
This student's response contains at least four errors spanning bonding, properties, sustainability, and energy transition. For each error, identify it and write a correction using specific chemistry knowledge from the unit.
| # | Identify the error (quote or describe it) | Correct it, use specific chemistry from the unit |
|---|---|---|
| 1 | ||
| 2 | ||
| 3 | ||
| 4 |
1. Multi-step question. Trace the journey of a PET drink bottle from crude oil extraction through to its ultimate fate as a microplastic in the ocean. At each stage below, name the relevant chemistry concept from Unit 2 and explain its significance.
| Stage | Chemistry concept from Unit 2 | Why it matters at this stage |
|---|---|---|
| 1. Crude oil extraction | ||
| 2. Fractional distillation / cracking to monomer | ||
| 3. Polymerisation to PET | ||
| 4. Use of the bottle (filling with liquid, UV exposure) | ||
| 5. Littering and breakdown to microplastics | ||
| 6. Microplastic fate in the ocean (bioaccumulation) |
2. A company claims its new bioplastic packaging will "completely solve the microplastics crisis" because it is plant-based and labelled "biodegradable".
(a) What part of this claim is supported by chemistry from the unit?
(b) What is misleading or overstated about this claim? Use the life cycle assessment concept and evidence about biodegradation conditions in your answer.
Wrap Up
What was the most important connection you made between chemistry and the real world in Unit 2?