Science at key stage 3 (Year 8)
Unit 8F: Compounds and mixtures
Section 3: Do compounds react chemically?
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Objectives |
| Children should learn: |
- to carry out test tube reactions
- to identify observations relevant to a piece of work and draw conclusions from these
- that compounds can react chemically
- to organise ideas into an appropriate sequence
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Activities |
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Outcomes |
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Children: |
- Ask pupils to carry out a number of test tube chemical reactions in which visible changes occur,
eg
- mixing sodium carbonate solution and iron (II) chloride solution
- adding dilute hydrochloric acid to solid magnesium carbonate
- adding dilute ammonia solution to copper sulphate solution
- heating sucrose
- Ask pupils to record their observations carefully, telling them that they are looking for evidence that chemical reactions making new materials have taken place. Ask pupils, in groups, to agree on a short paragraph about the reactions setting out the observations and evidence, then to exchange work and decide whether they agree or disagree with the evidence suggested, explaining their reasons.
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- identify appropriate indications of chemical reactions
- state that chemical reactions took place between the compounds
- summarise what they observed and explain what this showed
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Points to note |
- Pupils are likely to have explored chemical reactions in unit 7E 'Acids and alkalis', and unit 7F 'Simple chemical reactions'. This activity could be extended by asking pupils to think again about the evidence for a chemical reaction in the reactions explored in those units. Teachers may need to emphasise that some physical changes also involve colour changes and gas evolution, and that a chemical reaction is distinguished by changes in the ways the atoms are bonded together.
Safety
- 0.4 mol dm-3 solutions should be used. At this concentration, the substances named are low hazard, but eye protection should be worn
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This unit is divided into sections. Each section contains a sequence of
activities with related objectives and outcomes. You can view this unit by
moving through the sections or print/download the whole unit.
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