EquationBalancing

Some philosophical thoughts on balancing chemical equations
John Oversby: Institute of Education, University of Reading, UK

Introduction
Given the incompleteness of chemical reactions, can chemical equations be balanced? A major problem in traditional quantitative analytical chemistry was to ensure firstly that the materials used were pure, and secondly, that the reaction used for calculations proceeded 100% as written.

The issue of purity of analytical chemicals is a factor in choosing appropriate reactions for study. Many oxidants are converted directly into an equivalent quantity of iodine by reaction with iodide ions. This is largely because the stoichiometry of reaction between iodine and thiosulphate is well established to better than many volumetric analyses. Additionally, the end point is clearly indicated through the addition of starch, which forms a strong colour with free iodine.

However, a more significant issue is whether there are alternative outcomes for chemical reactions. These affect the overall equation, and make balancing even less significant.