Electrolysis: purifying copper
Lesson details
Learning outcome
I can investigate what happens when a solution of copper sulfate is electrolysed with copper electrodes.
Key learning points
- Purification of copper involves using copper electrodes in an electrolyte.
- The electrolyte must contain the same ions, in solution, as the metal being purified by electrolysis.
- Measuring the mass change in the copper electrodes demonstrates the transfer of copper.
- Impurities in the anode do not transfer to the cathode, leading to pure copper deposition.
- Other uses for this technique include electroplating, where you would use multiple metals e.g. gold.
Keywords
Pure - a single element or compound that is not mixed with any other substance
Anode - a positively charged electrode, in an electrolysis cell, to which the anions are attracted
Cathode - a negatively charged electrode, in an electrolysis cell, to which the cations are attracted
Electrolyte - a liquid or an aqueous salt solution that contains freely moving ions
Electroplating - a process that uses electricity to deposit a thin layer of metal onto the surface of another conductive object
Common misconception
Pupils do not always appreciate the difference between using inert carbon electrodes and metal electrodes, which will take part in the reaction.
Provide pupils with the opportunity to investigate the electrolysis of copper sulfate with both inert electrodes and with copper electrodes and then compare the results.
Teacher tip
Provide opportunities for pupils to apply their understanding of working with metal electrodes to different situations, such as electroplating a range of different metals.
Licence
except where otherwise stated. See Oak's terms & conditions (Collection 2).Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.Which electrode is positively charged in an electrolysis cell?
Q2.What is the role of the anode in an electrolysis cell?
Q3.What happens to negative ions during electrolysis?
Q4.What happens to positive ions during electrolysis?
Q5.What is produced at the cathode during the electrolysis of copper sulfate solution using copper electrodes?
Q6.Why must the electrolyte contain the same ions as the metal being purified?
Assessment exit quiz
6 Questions
Q1.What is the main purpose of using electrolysis in copper purification?
Q2.What happens to the mass of the anode during copper purification by electrolysis?
Q3.What is a common application of electrolysis besides purification?
Q4.What happens to impurities in the anode during copper purification?
Q5.To electroplate a bracelet using silver, the anode is...
Q6.Which of the following are benefits of electroplating?
To help you plan your 11 chemistry lesson on: Electrolysis: purifying copper, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 11 chemistry lesson on: Electrolysis: purifying copper, download all teaching resources for free and adapt to suit your pupils' needs.
The starter quiz will activate and check your pupils' prior knowledge, with versions available both with and without answers in PDF format.
We use learning cycles to break down learning into key concepts or ideas linked to the learning outcome. Each learning cycle features explanations with checks for understanding and practice tasks with feedback. All of this is found in our slide decks, ready for you to download and edit. The practice tasks are also available as printable worksheets and some lessons have additional materials with extra material you might need for teaching the lesson.
The assessment exit quiz will test your pupils' understanding of the key learning points.
Our video is a tool for planning, showing how other teachers might teach the lesson, offering helpful tips, modelled explanations and inspiration for your own delivery in the classroom. Plus, you can set it as homework or revision for pupils and keep their learning on track by sharing an online pupil version of this lesson.
Explore more key stage 4 chemistry lessons from the Electrolysis unit, dive into the full secondary chemistry curriculum, or learn more about lesson planning.