1. Chemical Reactions Unit
Part 3:
Reactions in Aqueous Solutions

2. Objectives Describe the information found in a net ionic equation
Predict the formation of a precipitate in a double-replacement reaction

3. Important Vocabulary Complete ionic equation Spectator ion
Net ionic equation

4. Ionic Equations
When ionic compounds dissolve in water, the ions separate from each other and spread throughout the solution
For example:
KI (aq) = K+ (aq) + I- (aq)
Pb(NO3)2 (aq) = Pb2+ (aq) + 2NO3- (aq)
We can use these ions to write a ______________________, an equation that shows dissolved ionic compounds as dissociated free ions

5. Spectator Ions & Net Ionic Equations
An ion that appears on both sides of an equation and is not directly involved in the reaction is called a ___________
When you rewrite an equation leaving out the spectator ions, you have the net ionic equation
A __________shows only those particles involved in the reaction and is balanced with respect to both mass and charge

6. Total Ionic Equation Example
Notice that the potassium and the nitrate ions appear unchanged on both sides of the equation
This equation can be simplified by eliminating these ions because they don’t participate in the reaction

7. Practice Problem #1
Write the complete balanced ionic equation for the following reaction. Then identify the spectator ions and write the balanced net ionic equation. Silver nitrate and sodium chloride in solution in which a precipitate of silver chloride is formed.

8. Your Turn! Practice Problem #1
Write the complete balanced ionic equation for the following reaction. Then identify the spectator ions and write the balanced net ionic equation. Aqueous calcium hydroxide with phosphoric acid. The products are calcium phosphate and water

9. Predicting the Formation of a Precipitate
You can predict the formation of precipitate by using the general rules of solubility of ionic compounds
Will a precipitate form when aqueous solutions of Na2CO3 & Ba(NO3)2 are mixed?