Oxidation and Reduction - Redox Reactions

• What are redox reactions?

  Reactions where oxidation and reduction occur simultaneously
• What do displacement reactions involve?

  A more reactive metal displacing a less reactive one
• What does oxidation mean in terms of oxygen?

  Gaining of oxygen
• What does reduction mean in terms of oxygen?

  Loss of oxygen
• How can oxidation and reduction also be defined?

  As loss and gain of electrons
• What mnemonic helps remember oxidation and reduction?

  Oil rig
• What does "oil rig" stand for?

  Oxidation is loss, reduction is gain
• What happens to a magnesium atom when it loses two electrons?

  It becomes a two plus ion and is oxidized
• What occurs when magnesium gains two electrons?

  It is reduced to a neutral magnesium atom
• Why are redox reactions called so?

  Because they involve both reduction and oxidation
• What happens when magnesium reacts with dilute acid?

  Magnesium loses electrons and is oxidized
• What do hydrogen ions do in the reaction with magnesium?

  They gain electrons and are reduced
• 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?

  Particles that do not change in the reaction
• How can ionic equations be simplified?

  By removing spectator ions
• What do half equations show?

  The gain and loss of electrons for each element
• How do you write a half equation for calcium?

  Neutral calcium atom forms calcium two plus ion
• What must be added to balance the charges in half equations?

  Electrons
• How do you check if charges balance in half equations?

  Compare total charges on both sides
• What happens if the overall charges don't balance?

  Electrons are likely placed on the wrong side
• What are the key components of redox reactions?

  • Oxidation: loss of electrons
  • Reduction: gain of electrons
  • Occur simultaneously
  • Involve displacement reactions
• What is the process of writing ionic equations and half equations?

  1. Write the ionic equation.
  2. Remove spectator ions.
  3. Write half equations for each element.
  4. Balance charges with electrons.