Year 10 Science · Unit 2 · Lesson 8

Combustion and Other Reaction Types

Challenge Worksheet

Name

Date

Class

Learning Goals

Evaluate consequences of incomplete combustion at a systemic (environmental and health) scale.
Apply knowledge of combustion chemistry to explain why diesel particulate emissions are regulated.
Construct a multi-factor argument using chemical equations and real-world evidence.

Go Deeper

What if…?

Scenario

Imagine car manufacturers deliberately engineered petrol engines to run on incomplete combustion, that is, always operating with a limited oxygen supply so that the octane fuel (C₈H₁₈) never fully combusts. Instead of producing carbon dioxide and water, the engine exhaust would consistently contain carbon monoxide (CO) and solid soot (carbon particles). Australia's National Environment Protection (Ambient Air Quality) Measure sets national standards for particulate matter measured in ambient air; it does not set tailpipe limits. For a separate real-world comparison, the National Environment Protection (Diesel Vehicle Emissions) Measure aims to reduce pollution from in-service diesel vehicles, while Australian Design Rules set emissions standards for new vehicles. In this hypothetical scenario, regulations have been abandoned and all vehicles produce maximum incomplete combustion products.

Using what you know about combustion chemistry, predict and explain the environmental and health consequences of this scenario. In your answer: (i) write the incomplete combustion equation for octane; (ii) explain how CO affects human physiology; (iii) describe the environmental effects of soot (carbon particulates); and (iv) explain why diesel particulate regulations exist and what would happen without them. Use scientific terms throughout.

Challenge 4 marks

Show What You Know

1. A catalytic converter converts CO to CO₂ using a platinum catalyst. Evaluate whether this makes incomplete combustion "safe enough." In your answer, consider both the human health benefit AND any remaining environmental concerns.

Challenge 4 marks

2. During the 2019–20 Black Summer bushfires, extensive incomplete combustion of eucalyptus forests released enormous quantities of CO, soot, and particulate matter over eastern Australia. Using the chemistry of incomplete combustion, explain why bushfire smoke presents different health risks compared to smoke from a well-maintained gas heater.

Challenge 3 marks

Wrap Up

In one sentence, what was the main idea of this lesson?