Skill 8.8 Recognizing net ionic equations

When two or more pure materials mix in a homogeneous way (with their molecules intermixing on a molecular level), the mixture is called a solution. Particles in solution are free to move about and collide with each other, vastly increasing the likelihood that a reaction will occur compared with particles in a solid phase. Reactions among ions in aqueous solution are often represented in three ways. When solutions of hydrochloric acid and sodium hydroxide are mixed, a reaction occurs and heat is produced. The molecular equation for this reaction is  

It is called a molecular equation because the complete chemical formulas of reactants and products are shown. But in reality, both HCl and NaOH are strong electrolytes and exist in solution as ions. This is represented by a complete ionic equation that shows all the dissolved ions  

Because Na (aq) and Cl (aq) appear as both reactants and products, they play no role in the reaction. Ions that appear in identical chemical forms on both sides of an ionic equation are called spectator ions because they aren t part of the action. 

When spectator ions are removed from a complete ionic equation, the result is a net ionic equation that shows the actual changes that occur to the chemicals when these two solutions are mixed together  

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