Electrochemistry Concepts

Electrolysis

• Definition: Electrolysis is the process of decomposing a substance using an electric current.
• Types:
  • Electrolysis of water: 2H₂O → 2H₂ + O₂
  • Electrolysis of molten sodium chloride: 2NaCl → 2Na + Cl₂
• Applications:
  • Extraction of metals (e.g., aluminum, sodium)
  • Production of chemicals (e.g., chlorine, hydrogen)

Galvanic Cells

• Definition: A galvanic cell is an electrochemical cell that generates a spontaneous redox reaction, producing an electric current.
• Components:
  • Anode (oxidation occurs): where electrons are lost
  • Cathode (reduction occurs): where electrons are gained
  • Electrolyte: facilitates ion flow between anode and cathode
• Examples:
  • Zinc-copper galvanic cell
  • Daniel cell (zinc-copper sulfate)

Oxidation Reduction (Redox)

• Definition: Oxidation-reduction reactions involve the transfer of electrons between species.
• Oxidation: loss of electrons
• Reduction: gain of electrons
• Redox reactions:
  • Combustion reactions
  • Rusting of iron
  • Photosynthesis

Batteries

• Definition: A battery is a device that stores energy in the form of chemical energy, which can be converted into electrical energy.
• Types:
  • Primary batteries: non-rechargeable (e.g., alkaline, zinc-carbon)
  • Secondary batteries: rechargeable (e.g., lead-acid, lithium-ion)
• Components:
  • Anode
  • Cathode
  • Electrolyte
• Applications:
  • Portable electronics
  • Electric vehicles
  • Renewable energy systems

Electrolysis

• Decomposing a substance using an electric current, resulting in the breakdown of a compound into simpler components.
• Two types of electrolysis:
  • Electrolysis of water, which produces hydrogen and oxygen gases (2H₂O → 2H₂ + O₂).
  • Electrolysis of molten sodium chloride, which produces sodium and chlorine (2NaCl → 2Na + Cl₂).
• Applications of electrolysis include:
  • Extraction of metals like aluminum and sodium from their ores.
  • Production of chemicals like chlorine and hydrogen.

Galvanic Cells

• A galvanic cell is an electrochemical cell that generates a spontaneous redox reaction, producing an electric current.
• Components of a galvanic cell include:
  • Anode, where oxidation occurs and electrons are lost.
  • Cathode, where reduction occurs and electrons are gained.
  • Electrolyte, which facilitates the flow of ions between the anode and cathode.
• Examples of galvanic cells include:
  • Zinc-copper galvanic cell.
  • Daniel cell, a type of zinc-copper sulfate galvanic cell.

Oxidation Reduction (Redox)

• Oxidation-reduction reactions involve the transfer of electrons between species.
• Oxidation is the loss of electrons, while reduction is the gain of electrons.
• Examples of redox reactions include:
  • Combustion reactions, which involve the burning of fuels.
  • Rusting of iron, which is a slow oxidation process.
  • Photosynthesis, which involves the conversion of light energy into chemical energy.

Batteries

• A battery is a device that stores energy in the form of chemical energy, which can be converted into electrical energy.
• Two types of batteries:
  • Primary batteries, which are non-rechargeable (e.g., alkaline, zinc-carbon).
  • Secondary batteries, which are rechargeable (e.g., lead-acid, lithium-ion).
• Components of a battery include:
  • Anode, which is the negative electrode.
  • Cathode, which is the positive electrode.
  • Electrolyte, which facilitates the flow of ions between the anode and cathode.
• Applications of batteries include:
  • Powering portable electronics.
  • Electric vehicles.
  • Renewable energy systems.