Water from a reservoir contains sand and grit, fine clay particles, bacteria and dissolved salts. It is treated by sedimentation, then filtration, then chlorination. Which of these is still present in the treated water?
fine clay particles
living bacteria
dissolved salts
no impurities at all
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.