A student investigates the mass of copper produced when copper chloride solution in a beaker is electrolysed using inert electrodes - Edexcel - GCSE Chemistry - Question 6 - 2023 - Paper 1
Question 6
A student investigates the mass of copper produced when copper chloride solution in a beaker is electrolysed using inert electrodes.
(a) Where is copper formed duri... show full transcript
Worked Solution & Example Answer:A student investigates the mass of copper produced when copper chloride solution in a beaker is electrolysed using inert electrodes - Edexcel - GCSE Chemistry - Question 6 - 2023 - Paper 1
Step 1
Where is copper formed during the electrolysis?
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Answer
Copper is formed at the cathode (C) during the electrolysis process. This is because during electrolysis, cations migrate towards the cathode where they gain electrons (reduction) and precipitate as solid copper.
Step 2
State and explain the trend shown in these results.
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Answer
The trend shown in the results indicates that as the current increases, the mass of copper formed also increases. This relationship can be explained by the principle of electrolysis, where the amount of substance deposited at the electrodes is directly proportional to the electric current (according to Faraday's laws of electrolysis). Specifically, the formula for calculating mass deposited is given by:
m = rac{Q}{nF}
where:
m = mass of the substance deposited
Q = total electric charge (current multiplied by time)
n = number of moles of electrons transferred
F = Faraday's constant (approximately 96500 C/mol).
As current increases, assuming the time remains constant, the total charge (Q) also increases, leading to more copper being deposited.