This question is about zinc and compounds of zinc - AQA - GCSE Chemistry - Question 4 - 2022 - Paper 1
Question 4
This question is about zinc and compounds of zinc.
A student produces pure crystals of zinc chloride by reacting zinc oxide with hydrochloric acid.
The equation fo... show full transcript
Worked Solution & Example Answer:This question is about zinc and compounds of zinc - AQA - GCSE Chemistry - Question 4 - 2022 - Paper 1
Step 1
Give one observation that the student could make to show that the zinc oxide is in excess.
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Answer
The student could observe that some zinc oxide solid remains at the bottom of the reaction vessel, indicating that it has not reacted completely with the hydrochloric acid.
Step 2
Why is excess zinc oxide used rather than excess hydrochloric acid?
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Excess zinc oxide can be filtered off easily after the reaction, allowing for the complete separation from the zinc chloride solution.
Step 3
Name one other compound that the student could add to hydrochloric acid to produce zinc chloride.
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The student could add zinc hydroxide or zinc carbonate to hydrochloric acid to produce zinc chloride.
Step 4
Describe how the student should obtain crystals of zinc chloride from a solution of zinc chloride.
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The student should heat the solution until the crystallisation point is reached, allowing the solution to cool slowly to form crystals. To increase the yield, they could also allow the solution to evaporate slightly before cooling.
Step 5
Complete the ionic equation for this reaction.
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Answer
Zn+Cu2+→Zn2++Cu
Step 6
Why is zinc described as being oxidised in this reaction?
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Zinc is described as being oxidised because it loses electrons during the reaction, changing from neutral zinc atoms to zinc ions.
Step 7
Complete Figure 7 to show how zinc, copper and another substance can be used to light a lamp.
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Zinc and copper are inserted into an electrolytic solution in a container, connecting them to form a complete circuit with a lamp represented by the symbol (\times). The zinc acts as the anode and the copper as the cathode.
