Introduction to electrolyisis

• What are redox reactions?

  Reactions where oxidation and reduction occur simultaneously
• What are the key components covered in redox reactions?

  • Displacement reactions
  • Ionic equations
  • Half equations
• What does oxidation mean in one context?

  Gaining of oxygen
• What does reduction mean in one context?

  Loss of oxygen
• How can we determine if a substance has been oxidized or reduced?

  By observing the gain or loss of oxygen
• What mnemonic helps remember oxidation and reduction regarding electrons?

  Oil rig: Oxidation is loss, Reduction is gain
• If a magnesium atom loses two electrons, what happens to it?

  It becomes a magnesium two plus ion
• What happens when magnesium reacts with dilute acid?

  Magnesium loses electrons and forms magnesium ions
• What do hydrogen ions do in the reaction with magnesium and dilute acid?

  They gain electrons and become neutral hydrogen atoms
• What is a displacement reaction?

  A reaction where a more reactive metal displaces a less reactive one
• What happens when calcium is added to iron sulfate?

  Calcium displaces iron to form calcium sulfate
• What are spectator ions in a reaction?

  Ions that do not change during the reaction
• How do we write ionic equations for reactions?

  By showing only the particles that change
• What is a half equation?

  An equation showing gain or loss of electrons
• How do we balance charges in half equations?

  By adding electrons to the appropriate side
• What should you check when writing half equations?

  That the overall charge on each side balances
• What happens if the overall charges in a half equation do not balance?

  You likely placed electrons on the wrong side
• What are the steps to write a half equation for calcium?

  1. Write neutral calcium atom to calcium two plus ion
  2. Add two electrons to the right side
• What are the steps to write a half equation for iron?

  1. Write iron two plus ion to iron atom
  2. Add two electrons to the left side