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When copper sulfate solution is electrolysed using copper electrodes, the mass of each electrode changes - Edexcel - GCSE Chemistry: Combined Science - Question 3 - 2022 - Paper 1
Question 3
When copper sulfate solution is electrolysed using copper electrodes, the mass of each electrode changes. (a) Draw a labelled diagram to show the apparatus that can... show full transcript
Worked Solution & Example Answer:When copper sulfate solution is electrolysed using copper electrodes, the mass of each electrode changes - Edexcel - GCSE Chemistry: Combined Science - Question 3 - 2022 - Paper 1
Step 1
Draw a labelled diagram to show the apparatus that can be used to electrolyse copper sulfate solution using copper electrodes.
Answer
To illustrate the apparatus used for electrolysis, draw the following components:
- Beaker: A cylindrical container to hold the copper sulfate solution.
- Copper Electrodes: Two copper electrodes positioned inside the beaker, one acting as the cathode and the other as the anode.
- Power Supply: A direct current power supply connected to the electrodes to facilitate the electrolytic process.
Ensure each part is clearly labelled for full marks.
Step 2
Explain what should be done to the copper electrodes before their masses are determined.
Answer
Before determining the masses of the copper electrodes:
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Cleaning the Electrodes: Use an appropriate solvent (like distilled water or ethanol) to scrub and clean the surfaces of the electrodes. This will remove any surface oxide, dirt, or impurities that could affect the mass reading.
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Drying: Allow the electrodes to dry completely to ensure accurate mass measurements after cleaning.
Step 3
Figure 2 shows the results obtained from an electrolysis experiment when copper sulfate solution was electrolysed for 10 minutes.
Answer
This part requires analyzing the experimental results from Figure 2. For each electrode:
- At the Anode: Copper atoms lose electrons and dissolve into the solution, resulting in a loss of mass.
- At the Cathode: Copper ions in the solution gain electrons and are deposited as copper metal, causing an increase in mass.
The overall effect leads to a change in the mass of both the anode and cathode.