Redox reactions

• What are redox reactions?

  Reactions in which 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
• How can oxidation and reduction refer to electrons?

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

  It becomes a magnesium two plus ion and is oxidized
• What occurs when magnesium reacts with dilute acid?

  Magnesium loses electrons and is oxidized, while hydrogen ions gain electrons and are reduced
• What do we call reactions that involve both oxidation and reduction?

  Redox reactions
• What do spectator ions do in a reaction?

  They do not change or take part in the reaction
• How can we represent a displacement reaction as an ionic equation?

  By showing only the particles that change in the reaction
• How do we write half equations for redox reactions?

  By showing the gain and loss of electrons for each element involved
• What must be checked when writing half equations?

  The overall charge on each side must balance
• What happens to a neutral calcium atom in a half equation?

  It forms a calcium two plus ion by losing two electrons
• In the iron half equation, what happens to the Iron II plus ion?

  It gains two electrons to form a neutral iron atom
• What does it indicate if the overall charges on each side of a half equation do not match?

  Electrons may have been placed on the wrong side
• What are the key components of redox reactions?

  • Oxidation: loss of electrons or gaining of oxygen
  • Reduction: gain of electrons or loss of oxygen
  • Occur simultaneously in reactions
  • Involves displacement reactions and ionic equations
• How do you write an ionic equation for a displacement reaction?

  1. Identify the reactants and products
  2. Show only the particles that change
  3. Remove spectator ions
  4. Write the balanced ionic equation
• What is the process for writing half equations in redox reactions?

  1. Write the ionic equation for one element
  2. Show the gain or loss of electrons
  3. Ensure charge balance on both sides
  4. Repeat for other elements involved