Half Reaction Method

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The half reaction method is a way of balancing the chemical equations of redox reactions. This page will explain how to utilize the half reaction method. To understand this text the reader should understand how to balance regular chemical equations and have a working knowledge of oxidation states.

Contents 1 Introduction 2 Procedure 3 Example 4 Bibliography

[edit] Introduction

Oxidation reduction reactions, or "redox" reactions, are reactions in which the the oxidation state of an element changes. Unlike regular reactions they must be balanced not only in respect to the number of molecules of reactants but in respect to charge as well.

[edit] Procedure

1. Break the reaction down into "half reactions" one equation representing the oxidation portion of the reaction and the second one representing the reduction half of the reaction
2. Balance each half reaction
   1. Balance elements
   2. Balance oxygen using H₂O
   3. Balance hydrogen using H⁺
   4. Balance charge using electrons (e^-)
3. Multiply each half reaction by an integer so that the electrons will cancel
4. Combine the half reactions and then cancel out redundancies

[edit] Example

In this example solid copper is reacted with nitrate ions to produce aquas copper cations and nitrogen monoxide. This reaction occurs in an acidic solution. The unbalanced chemical formula for this reaction is below.

[edit] Bibliography

• Steven S. Zumdahl, Susan A. Zumdahl (2003). Chemistry. New York: Houghton Mifflin Company. ISBN 0-618-26505-8.