Key Stage 3 Science: Particles, Changes of State and Separating Mixtures

Chemistry for Year 7, England National Curriculum

A 12-question worksheet, a worked answer key and a 10-mark assessment with its answers, written to three statements of the Key Stage 3 science programme of study: the particle model, changes of state, and separating mixtures. Checked by a teacher.

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Edition 1.0 · November 2026. Your download link always gives the latest edition. Spotted something in a question or a marking note? Tell us in 30 seconds.

Cover of the Key Stage 3 Science: Particles, Changes of State and Separating Mixtures packA page of questions from the Key Stage 3 Science: Particles, Changes of State and Separating Mixtures pack

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Five questions from the pack, with the answer explained. They are marked in this page: your answers are not sent anywhere and are not kept.

  1. 1.A syringe full of air can be pushed in, but a syringe full of sand cannot. Why?

    KS3.C.1.1 · Worksheet A2

  2. 2.Substance X melts at −7 °C and boils at 59 °C. At 25 °C it is

    KS3.C.1.2 · Worksheet B6

  3. 3.Crushed ice is heated steadily, but the temperature stays at 0 °C until all of it has melted. What is the energy doing?

    KS3.C.1.2 · Worksheet B7

  4. 4.The best technique to obtain sand from a mixture of sand and water is

    KS3.C.3.4 · Worksheet C9

  5. 5.Ink X gives three spots, 2 cm, 4 cm and 7 cm above the start line. Dye P gives one spot 4 cm above the line; dye Q gives one spot 5 cm above it. Which dye is in ink X?

    KS3.C.3.4 · Worksheet C12

What is in it

The objectives

CodeWhat it covers
KS3.C.1.1Using the particle model to explain how solids, liquids and gases behave, gas pressure included.
KS3.C.1.2Using the particle model to explain changes of state: melting, freezing, evaporating, boiling and condensing.
KS3.C.3.4Choosing and using simple techniques to separate mixtures: filtration, evaporation, distillation and chromatography.

Contains public sector information licensed under the Open Government Licence v3.0. Statements from the Key Stage 3 science programme of study (Department for Education). The references (KS3.C.1.1 and so on) are our own; the National Curriculum does not number its statements. The descriptions, questions, answers and marking notes are our own work.

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