Chemical Reactions Unit Part 3: Reactions in Aqueous Solutions

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

Important Vocabulary Complete ionic equation Spectator ion Net ionic equation

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

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

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

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.

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

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?