Mastering Redox Equations with Half-Reactions

1. The Finish Line is in site… Electrochemistry

2. Balancing Redox Equations • It is essential to write a correctly balanced equation that represents what happens in a chemical reaction • We will be using the ½ reaction Method to balance redox reactions.

3. Using half-reactions • A half-reaction is an equation showing just the oxidation or just the reduction that takes place • They are then balanced separately, and finally combined

4. Step 1: write unbalanced equation in ionic form • Step 2: write separate half-reaction equations for oxidation and reduction • Step 3: balance the atoms in the half-reactions (Except O and H) • Step 4: Balance the O by adding water molecules to the other side Using half-reactions

5. Using half-reactions • Step 5: Balance the H atoms by adding H+ ions to the other side. • Step 6: add enough electrons to one side of each half-reaction to balance the charges • Step 7: multiply each half-reaction by a number to make the electrons equal in both • Step 8: add the balanced half-reactions to show an overall equation

6. Using half-reactions: In a basic solution • Step 9: add enough OH- ions to equal the number of H+ ions present • Step 10: form water molecules by combining OH- and H+ ions • Step 11: ‘clean-up’ the balanced equation by simplifying the water molecules if needed.