A manufacturer produces a sunscreen lotion and claims it is a formulation. Explain what is meant by a formulation and describe two features that make a sunscreen lotion an example of one.

WJEC GCSE Chemistry (Wales) — 1.4 The ever-changing Earth · Explain · 4 marks · View as Markdown

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

Model answer (4 marks)

A formulation is a mixture designed for a particular use.
1. It contains exact, carefully measured quantities of pure substances.
2. Each component has a specific purpose in the product.
3. The components are mixed in precise proportions to give the sunscreen its required properties.

Examiner tips

  • Use the term "formulation" exactly as defined. Show that the mixture is for a specific use. Mention that the quantities are exact and components are pure. Explain the purpose of at least two components and the need for precise mixing.

Common mistakes

  • Using vague phrases like "a mixture" without noting the purpose. Failing to state that the quantities are exact or that components are pure. Omitting the link between component purpose and the product’s properties.

Mark scheme (4 marks)

  1. A formulation is a mixture designed for a particular use
  2. It is made up of exact/carefully measured quantities of pure substances
  3. Each chemical/component in the sunscreen has a particular purpose
  4. The components are mixed in specific quantities to give the product the required properties

Key terms in this question

formulation

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