A waste-treatment company places equal masses of food-processing waste into two aerated containers. Decomposer microorganisms are added to each container.
The water supply, oxygen supply and mass of microorganisms are the same in both containers. A sensor records the total volume of carbon dioxide released by the decomposers.
| Temperature / ∘C^{\circ}\mathrm{C}∘C | Time / days | Total volume of carbon dioxide released / cm3\mathrm{cm}^3cm3 |
|---|---|---|
| 18 | 15 | 360 |
| 34 | 8 | 512 |
Use the data to calculate how many times faster the waste decayed at 34∘C34^{\circ}\mathrm{C}34∘C than at 18∘C18^{\circ}\mathrm{C}18∘C.
Give your answer to 2 significant figures.
The manager concludes that operating the containers at any temperature above 34∘C34^{\circ}\mathrm{C}34∘C would increase the rate of decay.
Evaluate this conclusion.
83 exam-style questions on AQA GCSE Biology 7.2 Organisation of an ecosystem, covering 7.2.1 Levels of organisation, 7.2.2 How materials are cycled, 7.2.3 Decomposition, and 7.2.4 Impact of environmental change (HT only). Each one has a worked solution and a mark scheme showing where the marks go.