A chemical plant makes gases Y and Z by the reversible decomposition of gaseous compound X.
X(g)⇌Y(g)+Z(g) \mathrm{X(g) \rightleftharpoons Y(g) + Z(g)} X(g)⇌Y(g)+Z(g)The forward reaction is endothermic.
The table shows data for three operating plans.
| Operating plan | Temperature (∘C^\circ\mathrm{C}∘C) | Pressure (atmospheres) | Equilibrium yield of Y (%) | Production rate of Y (tonnes per hour) | Energy cost (£ per tonne of Y) |
|---|---|---|---|---|---|
| P | 400 | 50 | 38 | 1.8 | 42 |
| Q | 500 | 50 | 61 | 5.4 | 64 |
| R | 500 | 150 | 44 | 8.1 | 93 |
Explain the differences in equilibrium yield between operating plans P, Q and R.
Evaluate which operating plan the chemical plant should use.
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.