GCSE Chemistry revision

The process of electrolysis

Electrolysis

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High Melting and Boiling Points: Ionic compounds consist of a giant lattice of oppositely charged ions held together by strong electrostatic forces of attraction, requiring large amounts of energy to break.
Electrical Conductivity: Ionic solids cannot conduct electricity because their ions are fixed in place within the lattice; when molten or dissolved in water (aqueous), the lattice breaks down, allowing ions to move freely and carry electrical charge.

1. Structure, Bonding, and Properties of Ionic Compounds AQA

High Melting and Boiling Points: Ionic compounds consist of a giant lattice of oppositely charged ions held together by strong electrostatic forces of attraction, requiring large amounts of energy to break.
Electrical Conductivity: Ionic solids cannot conduct electricity because their ions are fixed in place within the lattice; when molten or dissolved in water (aqueous), the lattice breaks down, allowing ions to move freely and carry electrical charge.

Definition of Electrolysis: Electrolysis is the chemical decomposition of an ionic compound—either in a molten state or in aqueous solution—caused by the passage of an electric current through it.
Cell Components: In a simple electrolytic cell, the positive electrode is the anode, the negative electrode is the cathode, and the liquid undergoing decomposition is the electrolyte.

2. Fundamentals and Key Terms of Electrolysis AQA

Definition of Electrolysis: Electrolysis is the chemical decomposition of an ionic compound—either in a molten state or in aqueous solution—caused by the passage of an electric current through it.
Cell Components: In a simple electrolytic cell, the positive electrode is the anode, the negative electrode is the cathode, and the liquid undergoing decomposition is the electrolyte.

Anode Reactions (Oxidation): Negative ions move to the positive anode where they lose electrons to form neutral atoms or molecules (oxidation). For example:
2Cl⁻ → Cl₂ + 2e⁻
Cathode Reactions (Reduction): Positive ions move to the negative cathode where they gain electrons to form neutral atoms or molecules (reduction). For example:
Cu²⁺ + 2e⁻ → Cu

3. Half-Equations for Anode and Cathode Reactions AQA

Anode Reactions (Oxidation): Negative ions move to the positive anode where they lose electrons to form neutral atoms or molecules (oxidation). For example:
2Cl⁻ → Cl₂ + 2e⁻
Cathode Reactions (Reduction): Positive ions move to the negative cathode where they gain electrons to form neutral atoms or molecules (reduction). For example:
Cu²⁺ + 2e⁻ → Cu