Mixtures and separation · 4 parts · syllabus 12.1, 12.4

The salt disappears. Has it gone?

Follow a mixture from the first stir to the final separation. Discover what dissolves, what stays behind and how to get a substance back.

Start learning Explore the experiment

Salt remains after water is removed from the salt solution.

Follow the idea

Filter paper holds back sand while salt solution collects in the beaker below.

The experiment · One sample · follow every component

Run it yourself, or project it for the class

Use the apparatus step by step and look closely at what happens. The whole experiment fits one screen, so it works on a projector too.

Open the experiment

Final check

Explain it on your own across all four parts. Hints and keys stay closed until you submit.

Take the final check

Return and recall

Come back after one to two weeks and answer with the lesson closed.

Recall questions

For teachers

Printable worksheets with their answer keys, the final check and the return questions for this module.

Open the teacher pack

Your saved work

Answers and earlier attempts stay in this browser. Export a copy to keep, to move to another device or to hand to your teacher. Importing a copy keeps your current answers and adds earlier attempts.

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Scope and sources

Cambridge IGCSE Chemistry 0620 · 2026–2028 v2 · Original learning materials.

Solvent, solute, solution, residue and filtrate; selective dissolution, filtration and bounded method choice. The experiment includes magnetic collection and salt recovery. Saturation, full crystallisation, distillation and chromatography need later lessons.

Apparatus, amounts and times in the experiment are illustrative. Real practical work follows a teacher-approved safety method.

Official Cambridge syllabus

The salt disappears. Has it gone?

Follow the idea

Where did the salt go?

What gets through the filter?

How can the salt return?

Which separation should come first?

Run it yourself, or project it for the class