Electrolysis: aqueous solutions practical

Combined science

Principles of electrolysis

Electrolysis of molten salts

Electrolysis: extracting aluminium

Electrolysis of aqueous solutions

Electrolysis: brine

Electrolysis: purifying copper

In the Using Earth's Resources unit, pupils learned about the extraction, production and uses of hydrocarbons from crude oil, as well as metal extraction.

This unit focuses on electrolysis, electrode reactions, and predicting products, including competing reactions in solutions. It explains metal extraction through electrolysis and writing ionic equations. It also covers tests for gases like oxygen, hydrogen, carbon dioxide, and chlorine.

Electrolysis

Physical activity and equipment requiring safe use

Use of equipment that may require supervision for safety, e.g. scissors in KS1, needles, paint, knives, cooking.

It attracts negative ions and facilitates their oxidation.

It attracts positive ions and facilitates their reduction.

What is the primary function of the cathode in electrolysis?

What are the observations at the anode during the electrolysis of copper (II) chloride solution?

Copper ions gain electrons and are reduced to copper metal.

Copper ions lose electrons and are oxidised to copper oxide.

Copper ions remain in solution and do not participate in the reaction.

What happens at the cathode during the electrolysis of copper (II) sulfate solution?

Copper ions gain electrons at the cathode and are reduced to copper metal.

Copper ions lose electrons at the cathode and are oxidised to copper oxide.

Explain why copper is deposited at the cathode during the electrolysis of copper (II) sulfate solution.

Chloride ions are discharged at the anode, releasing chlorine gas.

Hydroxide ions are discharged at the anode, releasing chlorine gas.

Sodium ions are discharged at the anode, releasing chlorine gas.

During the electrolysis of brine, why is chlorine gas collected at the anode?

The gas forms a white precipitate with acid.

A gas that facilitates electrical conduction.

A liquid or aqueous salt solution that contains freely moving ions.

A solid material that conducts electricity.

What is an electrolyte in the context of electrolysis?

What is formed when substances dissolve in water?

Through the absorption of heat by the liquid.

Through the movement of electrons in the liquid.

Through the movement of ions in the liquid.

How does electrical conductivity in liquids occur?

To increase the conductivity of the solution.

To prevent the electrodes from reacting with the electrolyte.

Why are inert electrodes used in electrolysis?

They are oxidised at the anode to form copper oxide.

They are reduced at the cathode to form copper metal.

What happens to copper ions during the electrolysis of copper sulfate solution?

What are the products at the anode during the electrolysis of brine?

Electrolysis: aqueous solutions practical

Lesson outcome

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