Bioleaching can be used to extract copper from low-grade sulfide ores.
The table shows five stages involved in this process.
| Stage | Process |
|---|---|
| 1 | Copper metal is recovered from the leachate using displacement with scrap iron or by electrolysis. |
| 2 | Bacteria are applied to a heap of low-grade copper sulfide ore. |
| 3 | The acidic, copper-rich solution (leachate) is collected at the base of the heap. |
| 4 | The bacteria oxidize the sulfide minerals, releasing soluble copper ions (Cu2+\text{Cu}^{2+}Cu2+). |
| 5 | Water is trickled through the ore heap to wash the dissolved copper ions downwards. |
What is the correct order for the stages?
2,4,5,3,12, 4, 5, 3, 12,4,5,3,1
2,5,4,3,12, 5, 4, 3, 12,5,4,3,1
4,2,5,3,14, 2, 5, 3, 14,2,5,3,1
2,4,3,5,12, 4, 3, 5, 12,4,3,5,1
81 exam-style questions on OCR GCSE Chemistry Improving processes and products. Each one has a worked solution and a mark scheme showing where the marks go.