Why is crystallisation preferable to heating a salt solution to complete dryness?
It removes insoluble solids from the salt solution
It produces a larger mass of the dry salt
It removes dissolved coloured impurities by filtering
It stops the salt decomposing and gives purer crystals
107 exam-style questions on Edexcel GCSE Chemistry 3.2 Methods of separating and purifying substances, covering 3.2.1 Pure substances and mixtures, 3.2.2 Techniques for separating mixtures, 3.2.3 Paper chromatography and Rf values, and 3.2.4 Making water potable. Each one has a worked solution and a mark scheme showing where the marks go.