An environmental chemist is analyzing run-off water collected near an industrial clay quarry to determine the concentration of dissolved heavy metal ions. Before carrying out the chemical analysis, the chemist passes the turbid water sample through a filtration column packed with layers of graded sand and gravel.
State the purpose of this filtration step.
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.