A paint manufacturer produces two paints, Paint A and Paint B. Paint A is described on the tin as a 'pure white paint'. Paint B is described as a 'formulation'. Explain what these two descriptions mean in chemistry, and describe one difference in how they would behave if their melting points were tested.

Eduqas GCSE Chemistry — 1.2 Atomic structure and the periodic table · Explain · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Model answer (4 marks)

Paint A is a pure substance – it contains only one element or compound and is not mixed with any other material.
Paint B is a formulation – a mixture of several pure substances that have been measured and combined for a specific purpose.
If their melting points were tested, Paint A would melt at one sharp, definite temperature.
Paint B would melt over a range of temperatures, not at a single sharp point.

Examiner tips

  • Use the words ‘pure substance’ and ‘formulation’ exactly as in the mark scheme.
  • Show the difference in melting behaviour – single temperature vs. range – to earn the full points.

Common mistakes

  • Calling a formulation a ‘pure’ substance or vice‑versa.
  • Failing to mention the melting‑point behaviour or describing it incorrectly.

Mark scheme (4 marks)

  1. In chemistry, a pure substance contains only one element or compound (not mixed with any other substance)
  2. A formulation is a mixture designed for a particular use, made up of exact (carefully measured) quantities of pure substances
  3. Paint A (pure substance) would melt at a single, sharp (specific) temperature
  4. Paint B (formulation/mixture) would melt over a range of temperatures (not at a single sharp point)

Key terms in this question

formulation · melting point

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