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Producing copper sulfate crystals
A student prepared copper sulfate by reacting an acid with excess copper carbonate.
Figure 3 shows the first two stages in the preparation of copper sulfate.
Beaker N contained copper sulfate solution.
Describe how the student could produce copper sulfate crystals from the copper sulfate solution in beaker N.
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Marking points
- 1 Heats or evaporates the solution to remove some water.
- 2 Leaves the solution to cool or crystallise.
Full-mark answer
Heat the copper sulfate solution to evaporate some of the water, then leave the concentrated solution to cool so that crystals form.
Why this answer loses marks
Filter the solution.
Filtration has already removed the excess solid and does not produce crystals from the solution; partial evaporation must be followed by cooling or crystallising.