A groundskeeper is selecting an NPK fertiliser for sports pitches. Each sack contains 25 kg of fertiliser.
| Fertiliser | Percentage of nitrogen by mass (%) | Cost per sack (£) |
|---|---|---|
| Fertiliser P | 16 | 12 |
| Fertiliser Q | 24 | 20 |
| Fertiliser R | 20 | 14 |
| Fertiliser S | 28 | 24 |
Which fertiliser gives the greatest mass of nitrogen for each pound spent?
Fertiliser Q
Fertiliser P
Fertiliser S
Fertiliser R
136 exam-style questions on OCR GCSE Chemistry 6.1 Improving processes and products, covering 6.1.1 Extracting metals industrially and by electrolysis, 6.1.2 Life cycle assessment and recycling, 6.1.3 Biological methods of metal extraction, 6.1.4 The Haber process and the production of fertilisers, 6.1.5 Alloys and their uses, 6.1.6 Corrosion and its prevention, 6.1.7 Comparing and selecting materials, and 6.1.8 Industrial conditions, rate and position of equilibrium. Each one has a worked solution and a mark scheme showing where the marks go.