Reaction Lab

Reactions in Aqueous Solutions: Metathesis Reactions and Net Ionic Equations

Introduction:
Metathesis or double decomposition reactions are a reaction in which two compounds react to form two new compounds, with no changes in oxidation number. The ions of two compounds exchange partners.
AX + BY  AY + BX
This reaction can occur between two inorganic salts when one product is insoluble in water, driving the reaction forward. A typical example is as followed and is considered a molecular equation.

BaCl2(aq) + 2AgNO3(aq)  Ba(NO3)2(aq)+2AgCl(s)

To better identify the strong electrolytes we write a more realistic equation as follows:

Ba2+(aq)+2Cl-(aq)+2Ag+(aq)+2NO3(aq)  Ba2+(aq)+2NO3-(aq)+2AgCl(s)

This is called an ionic equation an AgCl precipitates out of the solution. The compound that occurs on both sides of the equation are called spectator ions and do not enter into the reaction. When we eliminate the spectator ions a net ionic equation is formed, be sure to remove the symbols indication aqueous solution states.

Ag++ Cl-  AgCl(s)
Objective:
1. To determine the species present in aqueous solutions of compounds by using the solubility rules.
2. Predict the type of reaction that will occur when two aqueous solutions are mixed.
3. Write the chemical equation, the ionic equation, and the net ionic equation for metathesis reactions.
4. Identify unknown compound, experimentally, based on solubility, temperature, and crystallization.
Reagents and Media:

 1.0 M sodium acetate
 1.0 M sodium acid
 1.0 M sulfuric acid
 1.0 M sodium hydroxide
 Ice
 0.1 M lead nitrate
 0.1 M barium chloride
 1.0 M cadmium chloride
 1.0 M ammonium chloride
 potassium chloride
 0.1 M potassium chloride
 0.1 M copper (II) sulfate
 0.1 M trisodium phosphate
 0.1 M sodium sulfide
 0.1 M sodium nitrate