SCH4U - Balancing Redox Reactions - VI

List the steps required to balance half - reactions for acidic solutions (5).

1. Write and unbalanced half-reaction that shows the formulas of the given reactants and products

2. Balance any atoms other than oxygen and hydrogen first

3. Balance any oxygen atoms by adding water molecules

4. Balance any hydrogen atoms by adding hydrogen ions

5. Balance the charges by adding electrons

List the steps required to balance half - reactions for basic solutions (7).

1. Write and unbalanced half-reaction that shows the formulas of the given reactants and products

2. Balance any atoms other than oxygen and hydrogen first

3. Balance any oxygen and hydrogen atoms as if conditions were acidic

4. Adjust for basic conditions by adding to BOTH sides the same number of hydroxide ions as there are hydrogen ions

5. Simplify hydrogen ions and hydroxide ions into water molecules

6. Remove water molecules present on BOTH sides of the half-reaction

7. Balance the charges by adding electrons

List the steps required to balance redox reactions using the half - reaction method (8).

1. Write an unbalanced net ionic equation

2. Divide the net ionic equation into two half-reactions

3. Balance each half-reaction independently

4. Determine the least common multiple of the number of electrons in the half-reactions

5. Use coefficients to write each half-reaction so that it includes the least common multiple of electrons

6. Add the balanced half-reactions together

7. Remove the electrons from both sides

8. Remove identical molecules or ions from both sides

List the steps required to balance redox reactions using the oxidation - number method (8).

1. Write an unbalanced equation

2. Assign oxidation numbers to each element in the equation

3. Identify the elements that undergo an INCREASE in oxidation number or a DECREASE in oxidation number

4. Find the numerical values of the increase and the decrease in oxidation numbers

5. Determine the SMALLEST whole number ratio of the oxidized and reduced elements so that the total increase in oxidation numbers equals the total decrease in oxidation numbers

6. Use the smallest whole number ratio to balance the number of atoms

7. Balance the other elements

8. Do the additional steps for reactions in acidic or basic conditions