Net Ionic Equations Net Ionic Equations n describe

Net Ionic Equations

Net Ionic Equations… n …describe a chemical reaction in solution recognizing the role of dissociation.

3 steps n Non Ionic equation (aka balanced chemical equation) n Total ionic equation n Net ionic equation

Example n Solutions of lead (II) nitrate and potassium iodide are mixed.

Non ionic equation Pb(NO 3)2 (aq) + 2 KI (aq) ---> Pb. I 2(s) + 2 KNO 3 (aq)

Total ionic equation n Dissociate or ionize everything that is: n Aqueous and ionic n Aqueous and acid

Total ionic Pb(NO 3)2 (aq) + 2 KI (aq)---> Pb. I 2(s) + 2 KNO 3 (aq) Dissociate Pb 2+(aq) + 2 NO 3¯(aq) + 2 K+(aq) + 2 I¯(aq) ---> Pb. I 2(s) + 2 K+(aq) + 2 NO 3¯(aq) NOT aqueous so not dissociated

Spectator species (entities) n. A spectator species is a species (entity) that does not change in the reaction, is not involved in the reaction.

Cancel spectator species Total ionic equation: Pb 2+(aq) + 2 NO 3¯(aq) + 2 K+(aq) + 2 I¯(aq) ---> Pb. I 2(s) + 2 K+(aq) + 2 NO 3¯(aq) What remains is the net ionic equation.

Net ionic equation Pb 2+(aq) + 2 I¯(aq) ---> Pb. I 2(s)

Example Chlorine gas is bubbled through a solution of sodium fluoride. Non ionic equation: Cl 2(g) + 2 Na. F(aq) ---> F 2(g) + 2 Na. Cl(aq)

Total ionic equation Dissociate everything that is: Aqueous and ionic or aqueous and acid Cl 2(g) + 2 Na. F(aq) ---> F 2(g) + 2 Na. Cl(aq) Cl 2(g) + 2 Na+(aq) + 2 F¯(aq) ---> F 2(g) + 2 Na+(aq) + 2 Cl¯(aq)

Net Ionic Equation Cancel all spectator species: Cl 2(g) + 2 Na+(aq) + 2 F¯(aq) ---> F 2(g) + 2 Na+(aq) + 2 Cl¯(aq) What remains is the net ionic equation: Cl 2(g) + 2 F¯(aq) ---> F 2(g) + 2 Cl¯(aq)

Watch for: n Occasionally there are no spectator species. Then the total and the net are the same. n Occasionally all species in the total ionic equation are spectators, everything cancels. What does this mean? ?