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When heated, zinc carbonate decomposes to form zinc oxide and carbon dioxide gas - Edexcel - GCSE Chemistry - Question 1 - 2021 - Paper 1
Question 1
When heated, zinc carbonate decomposes to form zinc oxide and carbon dioxide gas. ZnCO₃ → ZnO + CO₂ (a) A student investigated the decomposition of a sample of zin... show full transcript
Worked Solution & Example Answer:When heated, zinc carbonate decomposes to form zinc oxide and carbon dioxide gas - Edexcel - GCSE Chemistry - Question 1 - 2021 - Paper 1
Step 1
Suggest how the student could confirm that the decomposition was complete.
Answer
To confirm that the decomposition of zinc carbonate was complete, the student should follow these steps:
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Heat the mixture for a longer duration: The student could extend the heating time beyond five minutes to ensure that the reaction has fully occurred.
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Measure the mass after additional heating: After heating the sample for a longer duration, the student should weigh the crucible and its contents again.
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Observe for constant mass: The decomposition is complete if the mass remains constant upon further heating. Any change in mass would indicate that not all of the zinc carbonate has decomposed.
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Check for fizzing: The absence of fizzing during heating can indicate that carbon dioxide gas is no longer being produced, suggesting that the decomposition is complete.
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Conduct a confirmation test: The student could add an acid to the heated residue (zinc oxide); if it reacts, this indicates the presence of zinc oxide and confirms that decomposition occurred.