electrolysis

• ELECTROLYSIS:


  A chemical process where an ELECTRIC CURRENT is used to break up an IONIC COMPOUND into their pure elements.

  
• ELECTROLYTE:


  The IONIC COMPOUND that is being separated.

  • It needs to be either MOLTEN or aqueous so it can conduct electricity, where the ions ARE free to move & go to their respective electrode.
  • When ionic compounds are SOLID, the ions are NOT free to move.

  
• ELECTRODES:


  Solid conductors that are generally made of metal or inert carbon.

  
• The two types of electrodes:

  Anode:

  • The positive electrode

  Cathode:

  • The negative electrode

  
• ELECTROLYSIS:

  • When electricity passes through the electrolyte, the free moving IONS MOVE to the electrodes.
  • POSITIVELY charged ions move to the CATHODE (negative) due to ATTRACTION of the OPPOSITE charges.
  • Similarly, NEGATIVELY charged ions are attracted to the ANODE (positive).
  • When the ions make contact with the electrodes, they DISCHARGE & turn into ATOMS of ELEMENTS.
  • Different types of reactions occur at each electrode.
• At the cathode:


  • Attracts positive ions (cations)
  • reduction occurs
  • positive ions gain electrons
  • positive ions form neutral atoms
• At the anode:

  • Attracts negative ions (cations)
  • oxidation occurs
  • negative ions lose electrons
  • Negative ions form neutral atoms
• Opposite charges attract

  
• To pass electricity through the electrolyte:


  • Connect the electrodes with some wire so the electrons can flow between them.
  • Add power supply like a battery to drive that flow of electrons.
  • The battery pass an electric current through the electrolyte.
  • Submerge the electrodes within the electrolyte.

  
• • A: Electrolyte
  • B: Cathode
  • C: battery
  • D: wire
  • E: Anode

  
• If a compound is soluble like copper sulfate (CuSO4), then dissolve it in water, so the aqueous copper sulfate would be the electrolyte.
• If a compound is insoluble like lead bromide (PuBr2), then melt it to get a molten liquid.

  • As that’s the only way to make sure the ions would be free to move around.
• Inert:

  It's unreactive, so will not take place in the reaction.
• Draw the cells with the shorter lines on the same side as the cathode.

  
• In electrolysis, the electrons travel Anode ➔ Cathode

  
• explain why the product at the negative electrode is not always a metal

  sometimes hydrogen is produces, bc the metal is more reactive than hydrogen