4.3.5.2 Combining half-equations to represent the overall

• What do half-equations illustrate about ions during electrolysis?

  They show ions gaining or losing electrons
• What are half-equations used for in electrolysis?

  They show reactions at each electrode
• What type of agent is a reducing agent associated with?

  Oxidation
• What is the relationship between the oxidizing agent and the reducing agent in this process?

  They are opposite and complementary
• What is the process of reduction in terms of electron transfer?

  Gains electrons
• What is the first step in adding balanced half-equations together?

  Write down your balanced half-equations
• What does a substance become after undergoing oxidation?

  Oxidized
• What are the key differences between the oxidation and reduction processes shown?

  • Oxidation: Compound A loses electrons
  • Reduction: Compound B gains electrons
  • Oxidation and reduction are opposite and complementary processes
• What is the mathematical formula to calculate the area of a circle with radius $r$?


  $A =$$\pi r^2$
• What is the name of the process shown in the image?

  Oxidation
• What type of agent is an oxidizing agent associated with?

  Reduction
• What happens at the cathode during electrolysis?

  • Reduction occurs
  • Electrons are gained
  • Example: `Cu2+ + 2e- → Cu`
• How do you find the lowest common multiple (LCM) of electron numbers?

  By determining the smallest multiple common to both
• What is the significance of the number of electrons in the overall cell reaction?

  They must be the same on both sides
• Why do you need to cancel electrons in a combined equation?

  To leave a balanced equation
• Why is it necessary to balance the number of electrons in half-equations?

  To eliminate electrons in the overall equation
• What is the total charge on the reactants in the equation `Fe + 2Ag+ → Fe2+ + 2Ag`?


  +2
• How do half-equations contribute to understanding the complete reaction in electrolysis?

  They represent individual processes at electrodes
• What is the total charge on the products in the equation `Fe + 2Ag+ → Fe2+ + 2Ag`?


  +2
• What are the steps to combine balanced half-equations?

  1. Write down balanced half-equations
  2. Combine reactants and products
  3. Cancel out electrons
• What are the steps to check if a chemical equation is balanced?

  • Count the number of each type of atom on both sides
  • Check that the total charge is the same on both sides
• What are the two types of compounds shown in the image?

  • Compound A (oxidized)
  • Compound B (reduced)
• What is the process that occurs at the anode?

  Oxidation
• What is the process that occurs at the cathode?

  Reduction
• What does canceling the `2e-` from both sides of the equation achieve?

  It leaves a balanced equation
• What happens to Compound A in the oxidation process?

  Compound A loses electrons
• What must be the same on both sides of a balanced equation?

  Number of each type of atom
• Why are half-equations important in electrolysis?

  They clarify the electron transfer processes
• What happens at the anode during electrolysis?

  • Oxidation occurs
  • Electrons are lost
  • Example: `Cl- → Cl2 + 2e-`
• In the equation `Fe + 2Ag+ → Fe2+ + 2Ag`, how many silver atoms are in the products?


  2
• What happens to Compound B in the reduction process?

  Compound B gains electrons
• What is the process of oxidation in terms of electron transfer?

  Loses electrons
• If compound B gains electrons, what process is it undergoing?

  Reduction
• What does a substance become after undergoing reduction?

  Reduced
• How do you determine if the equation `Fe + 2Ag+ → Fe2+ + 2Ag` is balanced?

  Check atoms and total charge on both sides
• What are the key differences between oxidation and reduction half-equations?

  • Oxidation:
  • Loses electrons
  • Becomes oxidized
  • Acts as reducing agent
  • Reduction:
  • Gains electrons
  • Becomes reduced
  • Acts as oxidizing agent
• What do you do after finding the LCM of the electron numbers?

  Multiply each half-equation by the necessary factor
• In the equation `Fe + 2Ag+ → Fe2+ + 2Ag`, how many iron atoms are in the reactants?

  1
• What do you do after writing down the balanced half-equations?

  Combine reactants and products from each equation
• What happens when you combine the reactants and products from the half-equations?

  You form the overall cell reaction