A student investigates the effect of temperature on the decomposition of leaves.
The Table shows her results.
Table
| Temperature in ∘C^\circ\text{C}∘C | Mass of leaves at the start in g\text{g}g | Mass of leaves after 8 weeks in g\text{g}g |
|---|---|---|
| 5 | 20.0 | 18.6 |
| 15 | 20.0 | 16.2 |
| 25 | 20.0 | 12.4 |
| 35 | 20.0 | 10.0 |
| 45 | 20.0 | 17.0 |
Calculate the percentage of the mass of leaves lost at 25 ∘C25\ ^\circ\text{C}25 ∘C.
Calculate the rate of decay at 35 ∘C35\ ^\circ\text{C}35 ∘C.
Give your answer in g per week.
Explain why less mass of leaves was lost at 5 ∘C5\ ^\circ\text{C}5 ∘C than at 35 ∘C35\ ^\circ\text{C}35 ∘C.
Explain why less mass of leaves was lost at 45 ∘C45\ ^\circ\text{C}45 ∘C than at 35 ∘C35\ ^\circ\text{C}35 ∘C.
The student dries the leaves in an oven before she weighs them.
Suggest why.
111 exam-style questions on OCR GCSE Biology 4.1 Ecosystems, covering 4.1.1 Cycling of materials in ecosystems, 4.1.2 Microorganisms in cycling materials, 4.1.3 The carbon and water cycles, 4.1.4 Factors affecting decomposition, 4.1.5 Levels of organisation in an ecosystem, 4.1.6 Abiotic and biotic factors affecting communities, 4.1.7 Interdependence and competition, 4.1.8 Trophic levels, 4.1.9 Pyramids of biomass, and 4.1.10 Efficiency of biomass transfers. Each one has a worked solution and a mark scheme showing where the marks go.