Myers Science Hub Premium • IGCSE Chemistry 0620

C4 Electrochemistry: Electrolysis Complete Lesson + 30-Mark Manual Practice

Covers the full 4.1 Electrolysis objectives: definition, cell components, ion movement, electrode products, electroplating, product prediction and half-equations. Responses submit to the backend for teacher manual grading.

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Syllabus Objectives Covered

Define electrolysis as decomposition of a molten or aqueous ionic compound by electric current.
Identify the anode as positive, cathode as negative, and electrolyte as the molten or aqueous substance undergoing electrolysis.
Describe charge transfer: electrons in the external circuit, electron gain/loss at electrodes, and ion movement in the electrolyte.
Identify products and observations for molten lead(II) bromide, concentrated aqueous sodium chloride and dilute sulfuric acid using inert electrodes.
Predict electrode products for binary molten compounds and aqueous halide solutions.
State why electroplating improves appearance and corrosion resistance, and describe how electroplating is done.
Construct ionic half-equations for oxidation at the anode and reduction at the cathode.

Electrolysis Toolkit

Cathode
Negative electrode. Cations gain electrons here. Reduction occurs.

Anode
Positive electrode. Anions lose electrons here. Oxidation occurs.

Electrolyte
Molten or aqueous ionic substance with mobile ions.

OIL RIG
Oxidation Is Loss; Reduction Is Gain of electrons.

Molten binary compounds
Metal at cathode; non-metal at anode.

Aqueous halides
Hydrogen or metal at cathode; halogen or oxygen at anode depending on ions/concentration.

Simple Electrolysis Cell

Anode (+)
Attracts anions
Oxidation: loss of electrons

Cathode (−)
Attracts cations
Reduction: gain of electrons

Cations → Cathode Anions → Anode

Electrons move through the external circuit; ions move through the electrolyte.

Embedded Video Learning Stations

1. What is electrolysis?

2. Molten compounds

3. Aqueous solutions

4. Predicting products

5. Half-equations

6. Electroplating

Teachers should preview videos before classroom use.

Guided Notes

1. Define electrolysis in your own words.

2. Explain what happens at the cathode and anode.

3. Describe how ions and electrons move during electrolysis.

4. Summarise the rules for predicting aqueous products.

5. Explain how electroplating works and why it is useful.

30-Mark Manual Practice

Answer all parts. Your responses will be sent to the backend sheet for manual marking by your teacher.