Describing Reactions in Solution

In this section we will consider the types of equations used to represent reactions in solution. For example, when we mix aqueous potassium chromate with aqueous barium nitrate, a reaction occurs to form a precipitate (BaCr04) and dissolved potassium nitrate. So far we have written the molecular equation for this reaction  

A strong electrolyte is a substance that completely breaks apart into ions when dissolved in water. 

Net ionic equations include only those components that undergo changes in the reaction. 

Although this equation shows the reactants and products of the reaction, it does not give a very clear picture of what actually occurs in solution. As we have seen, aqueous solutions of potassium chromate, barium nitrate, and potassium nitrate contain the individual ions, not molecules, as is implied by the molecular equation. Thus the complete ionic equation 

The complete ionic equation reveals that only some of the ions participate in the reaction. The K+ and N03- ions are present in solution both before and after the reaction. Ions such as these that do not participate directly in a reaction in solution are called spectator ions. The ions that participate in this reaction are the Ba2+ and Cr042- ions, which combine to form solid BaCr04  

This equation, called the net ionic equation, includes only those solution components directly involved in the reaction. Chemists usually write the net ionic equation for a reaction in solution because it gives the actual forms of the reactants and products and includes only the species that undergo a change. 

Three Types of Equations Are Used to Describe Reactions in Solution 

Unless otherwise noted, all arton this page is Cengage Learning 2014. 

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Three types of equations are used to describe reactions in solutions. 

Three types of equations are used to describe reactions in solution (1) the molecular equation, which shows the complete formihas of all reactants and products (2) the complete ionic equation, in which all reactants and products that are strong electrolytes are shown as ions and (3) the net ionic equation, which includes only those components of the solution that undergo a change. Spectator ions (those ions that remain imchanged in a reaction) are not included in a net ionic equation. 

Strong and Weak Electrolytes 4.6 Describing Reactions in Solution The Characteristics of Oxidation-... 

Reaction processes in condensed phase are a major challenge. To describe reactions in solution, one either has to resort to classical mechanics or has to include the coupling to the enviroment in a quantum simulation. Flux correlation functions provide a suitable theoretical framework for this purpose. However, the description of system-bath couplings in realistic quantum systems still is a serious theoretical problem and only first steps in this direction have been taken. 

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