Aim: How to write ionic equations DO NOW:

1. Watch the following video

2. Write your observations

3. Predict the products of AgNO3 and NaCl.

What is an aqueous solution?An aqueous solution is a solution in which the a substance is dissolved in water

Salts can usually dissolve in water. What happens to Ionic compounds when placed in water?

Complete Ionic EquationChemical equation:Pb(NO3)2 (aq) + Na2SO4(aq) PbSO4 (s) + 2NaNO3(aq)

Complete ionic equation (separate the compounds into their ionic components in aqueous solution; cannot separate solids in solutions):Pb2+(aq) + 2NO3

- (aq) + 2Na+(aq) + SO4

2-

(aq) PbSO4(s) + 2Na+(aq) + 2NO3-(aq)

Net Ionic EquationWriting the equation in ionic form shows which ions are really involved and which are not.

Pb2+(aq) + 2NO3- (aq) + 2Na+(aq) + SO4

2-(aq) PbSO4(s) + 2Na+(aq) + 2NO3

-(aq)Na+

and NO3- are on both sides of the equation.

They do not react; are just there to keep the solution electrically neutral. These ions are called spectator ions.

Net Ionic Equation cont.The net ionic equations is written by dropping out the spectator ions.Pb2+(aq) + SO4

2-(aq) PbSO4 (s)

The net ionic equation only focuses on the chemical species that are actually involved in the chemical reaction.

Predicting Formation of PrecipitatePrecipitation reactions involve the formation of an insoluble compound (does not dissolve), a precipitate, from the mixing of two soluble compounds. Example: PbSO4 is an insoluble compound in water.

Predicting Formation of Precipitate

Example 1

Predicting Precipitation Reactions:  Predict whether a precipitate will form when water solutions of silver nitrate, AgNO3(aq), and sodium sulfide, Na2S(aq), are mixed.  If there is a precipitation reaction, write the complete and net ionic equation that describes the reaction

Example 1Solution:Step 1: Determine what type of reaction it will be and the possible productsThe possible products from the mixture of AgNO3(aq) and Na2S(aq) are Ag2S and NaNO3. 

Step 2: Determine if any of the products are insoluble in water.According to Table F most sulfides are insoluble; therefore, Ag2S is insoluble.

Example 1Step 4: Write the chemical equation2AgNO3(aq) + Na2S(aq)  →  Ag2S(s) + 2NaNO3(aq)

Step 5: Write the net ionic equation from the complete ionic equation.2Ag+(aq) + 2NO3

- (aq) + 2Na+(aq) + S2-

(aq) → Ag2S(s) + 2Na+(aq) + 2NO3- (aq)

2Ag+(aq)  +  S2−(aq)  →  Ag2S(s)