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 is one meaning of oxidation?

  The gaining of oxygen
• What is one meaning of reduction?

  The loss of oxygen
• What happens to aluminum when it reacts with oxygen?

  It is oxidized to form aluminum oxide
• What does the mnemonic "oil rig" stand for?

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

  It becomes a magnesium two plus ion
• Why do oxidation and reduction reactions usually occur together?

  One substance loses electrons while another gains
• What are redox reactions also known as?

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

  Magnesium loses electrons and forms magnesium ions
• What do hydrogen ions become when they gain electrons?

  Neutral hydrogen atoms in hydrogen gas
• What do displacement reactions involve in terms of reactivity?

  A more reactive metal displacing a less reactive one
• What are spectator ions?

  Ions that do not change during the reaction
• How can ionic equations be simplified?

  By removing spectator ions from the equation
• What is a half equation?

  An equation showing gain or loss of electrons
• How do you write a half equation for calcium?

  Neutral calcium atom forms calcium two plus ion
• How do you balance charges in half equations?

  Add electrons to make charges equal on both sides
• What happens in the iron half equation?

  Iron II plus ion gains two electrons to form iron
• What should you check in half equations?

  That overall charges on each side balance
• What happens if charges in half equations don't balance?

  You likely placed electrons on the wrong side
• What are the steps to write ionic equations from displacement reactions?

  1. Identify the reactants and products.
  2. Write the full ionic equation.
  3. Remove spectator ions.
  4. Write the simplified ionic equation.
• What are the key features of redox reactions?

  • Involves oxidation and reduction
  • Electrons are transferred between substances
  • Often occur simultaneously
  • Can be represented as half equations