1.  DO NOW:  1. Watch the following video  2. Write your observations  3. Predict the products of AgNO 3 and NaCl.

2.  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?

3.  Chemical equation:  Pb(NO 3 ) 2 (aq) + Na 2 SO 4 (aq)  PbSO 4 (s) + 2NaNO 3 (aq)  Complete ionic equation (separate the compounds into their ionic components in aqueous solution; cannot separate solids in solutions):  Pb 2+ (aq) + 2NO 3 - (aq) + 2Na + (aq) + SO 4 2- (aq)  PbSO 4 (s) + 2Na + (aq) + 2NO 3 - (aq)

4.  Writing the equation in ionic form shows which ions are really involved and which are not.  Pb 2+ (aq) + 2NO 3 - (aq) + 2Na + (aq) + SO 4 2- (aq)  PbSO 4 (s) + 2Na + (aq) + 2NO 3 - (aq)  Na + and NO 3 - 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.

5.  The net ionic equations is written by dropping out the spectator ions.  Pb 2+ (aq) + SO 4 2- (aq)  PbSO 4 (s)  The net ionic equation only focuses on the chemical species that are actually involved in the chemical reaction.

6.  Precipitation reactions involve the formation of an insoluble compound (does not dissolve), a precipitate, from the mixing of two soluble compounds. Example: PbSO 4 is an insoluble compound in water.

8.  Predicting Precipitation Reactions: Predict whether a precipitate will form when water solutions of silver nitrate, AgNO 3 (aq), and sodium sulfide, Na 2 S(aq), are mixed. If there is a precipitation reaction, write the complete and net ionic equation that describes the reaction

9.  Solution:  Step 1: Determine what type of reaction it will be and the possible products  The possible products from the mixture of AgNO 3 (aq) and Na 2 S(aq) are Ag 2 S and NaNO 3.  Step 2: Determine if any of the products are insoluble in water.  According to Table F most sulfides are insoluble; therefore, Ag 2 S is insoluble.

10.  Step 4: Write the chemical equation  2AgNO 3 (aq) + Na 2 S(aq) → Ag 2 S(s) + 2NaNO 3 (aq)  Step 5: Write the net ionic equation from the complete ionic equation.  2Ag + (aq) + 2NO 3 - (aq) + 2Na + (aq) + S 2- (aq) → Ag 2 S(s) + 2Na + (aq) + 2NO 3 - (aq)  2Ag + (aq) + S 2− (aq) → Ag 2 S(s)