Oxidation and Reduction

• What are redox reactions?

  Reactions in which oxidation and reduction both take place at the same time
• What does oxidation mean in terms of oxygen?

  Oxidation is the gaining of oxygen
• What does reduction mean in terms of oxygen?

  Reduction is the loss of oxygen
• What happens when aluminum reacts with oxygen?


  Aluminum is oxidized to form aluminum oxide
• How can oxidation and reduction also refer to electrons?

  Oxidation refers to the loss of electrons, while reduction refers to the gain of electrons
• What mnemonic do most people use to remember oxidation and reduction?

  Oil rig, which stands for oxidation is loss, reduction is gain
• If a magnesium atom loses two electrons, what happens to it?


  It becomes a magnesium two plus ion and is oxidized
• What occurs simultaneously in redox reactions?

  If one substance loses electrons, another substance must gain them
• What does the term redox stand for?

  Reduction oxidation reactions
• What happens when magnesium reacts with dilute acid?

  Magnesium loses electrons and is oxidized, while hydrogen ions 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 a solution of iron sulfate?

  Calcium displaces iron to form calcium sulfate, while iron precipitates out as a solid
• What are spectator ions?

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


  By removing spectator ions and showing only the particles that change
• What are half equations?

  Equations that show the gain and loss of electrons for each element involved
• How do you write a half equation for calcium?

  A neutral calcium atom goes to form a calcium two plus ion, losing two electrons
• How do you write a half equation for iron?


  The Iron II plus ion goes to form an iron atom by gaining two electrons
• How can you check if the overall charge balances in half equations?

  By ensuring the total charge on each side is the same
• What should you do if the overall charges on each side of a half equation aren't the same?

  You may have placed your electrons on the wrong side
• What are the key concepts of redox reactions?

  • Oxidation: gaining oxygen or losing electrons
  • Reduction: losing oxygen or gaining electrons
  • Mnemonic: Oil rig (Oxidation is Loss, Reduction is Gain)
  • Simultaneous occurrence of oxidation and reduction
  • Involvement of spectator ions in ionic equations
• What are the steps to write half equations?

  1. Write the ionic equation for one element.
  2. Add electrons to balance the charges.
  3. Ensure the overall charge on each side is the same.
  4. Repeat for other elements involved in the reaction.