A student has a mixture of copper sulfate solution and some solid copper oxide that has not dissolved.
The student wants to obtain pure, dry crystals of copper sulfate.
Which method should the student use?
Filter the mixture, warm the filtrate to evaporate some water, then leave it to crystallise.
Heat the mixture until all the water has evaporated, then filter the solid that remains.
Leave the mixture to crystallise, then filter the crystals away from the copper oxide.
Filter the mixture, then collect the solid left on the filter paper and dry it.
51 exam-style questions on OCR GCSE Chemistry 2.1 Purity and separating mixtures, covering 2.1.1 Pure substances and melting point data, 2.1.2 Relative formula mass and empirical formula, 2.1.3 Formulations as useful mixtures, 2.1.4 Techniques for separating mixtures, and 2.1.5 Chromatography and Rf values. Each one has a worked solution and a mark scheme showing where the marks go.