Year 9 Science · Unit 2 · Lesson 14
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Learning Goals
Real-world context
In poorly ventilated garages or homes, petrol-powered generators or gas heaters can produce carbon monoxide (CO) at concentrations high enough to be fatal within minutes. In Australia, approximately 20 people die each year from CO poisoning from faulty gas appliances or misused generators. CO is colourless and odourless, making it impossible to detect without a dedicated alarm.
(a) Explain the chemistry behind why an appliance with a limited oxygen supply produces CO instead of CO₂.
(b) Explain the biological reason CO is more dangerous than CO₂ at similar concentrations.
Read the graph
Study the bar chart showing CO₂ emissions per kilometre for different vehicle types, then answer the questions below.
Data: Australian Government, National Greenhouse Accounts (vehicle emission factors); International Energy Agency, 2023.
(a) Which vehicle produces the most CO₂ per kilometre?
(b) The electric car charged from coal-fired power still shows 90 g CO₂/km. Explain why an electric car that produces no exhaust still has CO₂ emissions.
(c) If Australia's electricity grid moved fully to renewable energy, predict the effect on total transport CO₂ emissions. Use data from the graph to support your answer.
1. A gas heater shows a yellow flame instead of a blue one. Using your knowledge of combustion chemistry, explain what this indicates and what products are likely being released into the room.
2. Petrol cars emit approximately 180 g CO₂/km. Using the word equation for complete combustion, explain why switching to longer hydrocarbon fuels (such as diesel with longer carbon chains) would increase CO₂ output per litre of fuel burned.
Wrap Up
In one sentence, what was the main idea of this lesson?