A bottle of drinking water is labelled "pure spring water".
Statement 1: when a sample is evaporated to dryness, a small amount of white solid remains
Statement 2: when a sample is cooled, it starts to freeze just below 0 ∘C0\,^\circ\mathrm{C}0∘C and freezes over a range of temperatures
Statement 3: the water passes through filter paper, leaving nothing on the paper
Which observations show that, in the chemical sense, the water is not pure?
1 only
1 and 2 only
2 and 3 only
1, 2 and 3
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.