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Introduction to Electrochemistry

Jul 17, 2024

Introduction to Electrochemistry

What is Electrochemistry?

  • Relationship between chemical reactions and electricity

Two Main Interactions

  1. Chemical reactions creating electricity
    • Example: Batteries
  2. Electricity inducing chemical reactions
    • Example: Electrolysis

Understanding Electricity

  • Movement of electrons
  • Commonly through wires, batteries, etc.

Oxidation-Reduction (Redox) Reactions

  • Involves movement of electrons
  • Two scenarios:
    1. Creating electricity: Electrons move between atoms in redox reactions
    2. Using electricity: Forcing electrons to move between atoms in redox reactions

Creating Electricity using Redox Reactions

  • Example: Using a wire
    • Separate A and B: Electrons move through a wire; creates electricity

Using Electricity to Induce Redox Reactions

  • Example: Using a battery
    • Force electrons: Pull from C and push to D using electrical energy

Example: Galvanic/Voltaic Cells

  • Device used to make electricity from chemical reactions
  • Components:
    • Zinc (Zn) and Copper (Cu) metals
  • Reaction:
    • Zn loses electrons, becomes Zn²⁺
    • Cu²⁺ gains electrons, becomes neutral Cu
    • Spontaneous process: Happens on its own
  • Standard Reduction Potentials:
    • Chart listing elements/compounds by electron affinity
  • Electrode Terminology:
    • Anode: Site of oxidation (Zn)
    • Cathode: Site of reduction (Cu)
    • Mnemonic: An Ox Red Cat: Anode Oxidation, Reduction Cathode

Example: Electrolysis

  • Electrolytic Cell: Uses electricity to split water
  • Reaction:
    • H₂O → H₂ + O₂
    • Oxidation: Oxygen loses electrons
    • Reduction: Hydrogen gains electrons
    • Non-spontaneous: Needs electrical energy
  • Battery Role:
    • Pull electrons from oxygen
    • Push electrons to hydrogen
  • Electrode Terminology:
    • Anode: Oxygen oxidation
    • Cathode: Hydrogen reduction

Conclusion

  • Two main interactions: Chemical reactions creating electricity, and electricity inducing chemical reactions
  • Devices: Galvanic/Voltaic cells for spontaneous reactions, Electrolytic cells for non-spontaneous reactions
  • Key Concept: Electron movements are central to both processes

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