A carton of orange juice has the label "100% pure orange juice".
State what is meant by a pure substance in chemistry.
Explain why orange juice is not pure in the chemical sense.
A student tests two samples of a colourless liquid by freezing them and then measuring their melting points.
| Sample | Melting point |
|---|---|
| A | melts at exactly 0 °C |
| B | melts gradually between −4 °C and −1 °C |
Give the letter of the pure sample. Give a reason for your answer.
Give the names of the two mixtures in this list: oxygen, air, water, sea water.
48 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.