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

Fill in the missing effects. Each cause leads to the next step in the chain. The first and last boxes are given, fill in the four missing effects.

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.