MnO 2 Oxidation Reduction Step 2Balance each half reaction with regard to atoms

# Mno 2 oxidation reduction step 2balance each half

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MnO 2 Oxidation: Reduction: Step 2: Balance each half reaction with regard to atoms other than O and H. Oxidation: Reduction: CN CNO MnO 4 MnO 2
Balancing Redox Reactions Step 3: Balance O by adding H 2 O. Oxidation: Reduction: Step 4: Balance H by adding H + . Oxidation: Reduction: H 2 O + CN CNO MnO 4 MnO 2 + 2H 2 O H 2 O + CN CNO + 2H + 4H + + MnO 4 MnO 2 + 2H 2 O Balance the following reaction in basic solution: CN + MnO 4 CNO + MnO 2
Balancing Redox Reactions Step 5: Balance charge by adding electrons. Oxidation: Reduction: –1 –1 0 0 Total charge: Total charge: H 2 O + CN CNO + 2H + + 2e 3e + 4H + + MnO 4 MnO 2 + 2H 2 O Balance the following reaction in basic solution: CN + MnO 4 CNO + MnO 2
Balancing Redox Reactions Step 6: If the number of electrons in the half reactions are not equal, multiply as necessary to make them equal. Oxidation: Reduction: 3( ) Balance the following reaction in basic solution: CN + MnO 4 CNO + MnO 2 H 2 O + CN CNO + 2H + + 2e 3e + 4H + + MnO 4 MnO 2 + 2H 2 O 2( ) 3H 2 O + 3CN 3CNO + 6H + + 6e 6e + 8H + + 2MnO 4 2MnO 2 + 4H 2 O
6e + 8H + + 2MnO 4 2MnO 2 + 4H 2 O 3H 2 O + 3CN 3CNO + 6H + + 6e Balancing Redox Reactions Step 7: Add the half-reactions together and cancel electrons Oxidation: Reduction: 3CN + 2H + + 2MnO 4 3CNO + 2MnO 2 + H 2 O Balance the following reaction in basic solution: CN + MnO 4 CNO + MnO 2
Balancing Redox Reactions Step 8: Add one OH for every H + to both sides of the equation. 3CN + 2H + + 2MnO 4 3CNO + 2MnO 2 + H 2 O Balance the following reaction in basic solution: CN + MnO 4 CNO + MnO 2 + 2OH + 2OH 3CN + 2H 2 O + 2MnO 4 3CNO + 2MnO 2 + H 2 O + 2OH Step 9: Cancel water molecules as necessary. 3CN + H 2 O + 2MnO 4 3CNO + 2MnO 2 + 2OH
Balancing Redox Reactions • Write 2 half-reactions Identify the species oxidized and reduced • Balance the atoms others than O and H using the appropriate stoichiometric coefficients Balance O atoms adding H 2 O Balance H atoms adding H + Balance masses • Add electrons to the side with excess positive charge Balance charges • Multiply each half-reaction by a coefficient so that the number of electrons gained and lost are the same Balance electrons • Cancel terms that appear on both sides of the overall equation • IF SOLUTION IS ALKALINE: Add OH - on both sides and cancel out water as necessary. Combine the half-reactions
Electrochemical Cells A galvanic cell uses a spontaneous redox reaction G < 0) to generate electrical energy. The system does work on the surroundings. A electrolytic cell uses electrical energy to drive a nonspontaneous reaction (Δ G > 0). The surroundings do work on the system.
Electrochemical Cells