Starter quiz
- What are common signs that a chemical reaction is taking place?
- the substance melts
- bubbles appear ✓
- there is a colour change ✓
- the substance gets warmer ✓
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- In a chemical reaction, what happens to the atoms of the reactants?
- they disappear
- they rearrange to form new products ✓
- they change
- they become larger
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- What happens to the mass of the products compared to the mass of the reactants in a chemical reaction?
- it increases
- it decreases
- it stays the same ✓
- it fluctuates
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- What type of reaction involves a substance combining with oxygen?
- decomposition
- oxidation ✓
- neutralisation
- precipitation
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- To test for carbon dioxide, you would bubble the gas through ______. If carbon dioxide is present, the solution turns milky (cloudy).
- 'limewater' ✓
- Which of the following chemicals are reactants in this reaction? zinc + hydrochloric acid → zinc chloride + hydrogen
- zinc ✓
- hydrochloric acid ✓
- zinc chloride
- hydrogen
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Exit quiz
- What is a decomposition reaction?
- A reaction where two compounds combine to form one product.
- A reaction where a single compound breaks down into two or more products. ✓
- A reaction where a gas is produced by combining liquids.
- A reaction where heat is absorbed.
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- Decomposition reactions usually require ______, light, or electricity to occur.
- 'heat' ✓
- What gas is commonly produced when metal carbonates decompose?
- oxygen
- hydrogen
- nitrogen
- carbon dioxide ✓
- water
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- Which of the following is a decomposition reaction?
- 2H₂ + O₂ → 2H₂O
- CaCO₃ → CaO + CO₂ ✓
- NaCl + AgNO₃ → NaNO₃ + AgCl
- 2K + Cl₂ → 2KCl
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- When metal carbonates decompose upon heating, they typically form metal ______ and carbon dioxide gas.
- 'oxides' ✓
- Which of the following reactions represents the decomposition of water?
- 2H₂O → 2H₂ + O₂ ✓
- 2H₂ + O₂ → 2H₂O
- 2H₂O₂ → 2H₂O + O₂
- 2Li + 2H₂O → 2LiOH + H₂
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Worksheet
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Lesson Details
Key learning points
- Decomposition reactions involve a single compound breaking down into two or more products.
- Decomposition reactions usually require heat, light, or electricity, to occur.
- When metal carbonates decompose upon heating, they typically form metal oxides and carbon dioxide gas.
Common misconception
Pupils often struggle to understand that not all reactions consist of two substances mixed together to cause a reaction.
Show the symbol equation and how the reactants are rearranged to form the products.
Keywords
Decompose - When a substance decomposes it undergoes a decomposition reaction.
Decomposition - A type of reaction in which a reactant compound breaks down into two or more products.
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