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The order of reactivity of copper, magnesium and zinc can be determined by the displacement reactions between these metals and solutions of their salts - Edexcel - GCSE Chemistry: Combined Science - Question 5 - 2021 - Paper 1
Question 5
The order of reactivity of copper, magnesium and zinc can be determined by the displacement reactions between these metals and solutions of their salts. You are pro... show full transcript
Worked Solution & Example Answer:The order of reactivity of copper, magnesium and zinc can be determined by the displacement reactions between these metals and solutions of their salts - Edexcel - GCSE Chemistry: Combined Science - Question 5 - 2021 - Paper 1
Step 1
Describe the experiments that can be done to determine the order of reactivity of these metals by displacement reactions.
Answer
To establish the order of reactivity among copper, magnesium, and zinc:
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Set Up Reactions:
- Prepare three beakers and fill them with solutions of copper(II) sulfate, magnesium sulfate, and zinc sulfate respectively.
- Label each beaker clearly.
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Perform Displacement Reactions:
- Introduce a piece of copper into the magnesium sulfate solution and record any observations, such as color change or gas evolution.
- Repeat this with magnesium in the copper sulfate solution and zinc in magnesium sulfate, noting down any reactions.
- Finally, test zinc in copper sulfate.
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Analyze Results:
- The metal that displaces the other from the solution indicates higher reactivity. For example, if magnesium displaces copper, it is more reactive than copper.
- Count the number of reactions that occur: the greater the number of reactions observed, the more reactive the metal.
Step 2
Explain why aluminium cannot be extracted from its ore by heating with carbon but can be extracted by electrolysis.
Answer
Aluminium cannot be extracted from its ore by heating with carbon because:
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Reactivity of Aluminium:
- Aluminium is more reactive than carbon; in the thermodynamic sense, carbon cannot reduce aluminium oxide into metallic aluminium through heating alone.
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Electrolysis as an Effective Method:
- Electrolysis is a more powerful method of reduction, allowing aluminium ions to gain electrons at the cathode, effectively reducing them to metallic aluminium. This method provides the required energy to overcome the strong attractive forces in the bond between aluminium and oxygen.