A factory makes gaseous product Z in a reversible reaction. The forward reaction is exothermic.
2X(g)+Y(g)⇌2Z(g) \mathrm{2X(g) + Y(g) \rightleftharpoons 2Z(g)} 2X(g)+Y(g)⇌2Z(g)The factory tests three sets of conditions. Each test uses the same catalyst.
| Condition | Temperature (∘C^\circ\mathrm{C}∘C) | Pressure (atmospheres) | Production rate (tonnes of Z per hour) | Equilibrium yield of Z (%) | Operating cost (£ per tonne of Z) |
|---|---|---|---|---|---|
| A | 350 | 100 | 2.4 | 64 | 390 |
| B | 450 | 100 | 6.2 | 41 | 350 |
| C | 450 | 250 | 8.1 | 58 | 460 |
The factory must make at least 6.0 tonnes of Z per hour. Z can be sold for £420 per tonne.
Evaluate which condition the factory should use.
Use the data and ideas about rate and equilibrium in your answer.
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.