Year 10 Science · Unit 2 · Lesson 15

Controlling Reactions in Industry and Nature

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Learning Goals

Trace the chain from the Haber process through to food production using cause-and-effect reasoning.
Explain how temperature affects enzyme activity in fermentation using collision theory.
Distinguish between ethanol production by fermentation and CO₂ as a by-product.

Warm Up

Because… chain

Each row on the left is one step, and the next row is what happens after it. In the box, write the because — the reason that step forces the next one. Do not copy the next step’s words back; explain what makes it follow.

N₂ + 3H₂ ⇌ 2NH₃, the Haber process makes ammonia

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Ammonia is reacted with nitric acid or CO₂

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Fertiliser is spread on agricultural soil

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Plants absorb soil nitrates through roots

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Humans eat plant or animal protein

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~50% of nitrogen in human body came through the Haber process

Overall outcome:

Your Turn

Real-world context

Coopers Brewery in Adelaide, South Australia, is one of Australia's oldest family-owned breweries. To produce their ales, brewmasters carefully maintain fermentation tanks at approximately 35°C. Yeast enzymes convert glucose from malted barley into ethanol and CO₂ during anaerobic respiration. If the tank temperature rises above 40°C or drops below 15°C, the batch is considered at risk.

(a) Explain why the brewmaster keeps fermentation tanks at ~35°C rather than a higher temperature. Use your knowledge of enzyme activity in your answer.

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(b) A brewer accidentally chills a batch to 10°C overnight. Predict and explain what happens to fermentation rate, and what the brewer should do to recover the batch.

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(c) Write the word equation for the fermentation reaction that occurs in the brewing tank. Identify whether this is aerobic or anaerobic respiration.

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Wrap Up

In one sentence, explain why temperature control is critical in both industrial chemistry and biological processes.