1 EXCHANGEGas-FormingReactions REACTIONS

2

3 Gas Forming Reactions

4 EXCHANGEAcid-BaseReactions REACTIONS

5 Solutions that conduct electricity are called ELECTROLYTES Strong electrolytes dissociate completely (or nearly so) into ions. Aqueous Solutions

6. Acids that ionize only to a small extent are called weak electrolyte. CH 3 CO 2 H(aq) ---> CH 3 CO 2 - (aq) + H + (aq)

7 Aqueous Solutions Some compounds dissolve in water but do not conduct electricity. They are called nonelectrolytes. Examples include: sugarethanol ethylene glycol Examples include: sugarethanol ethylene glycol

8 Know the strong acids & bases!

9 9 Strong Acids ANION

10  Base  OH - in water BASES NaOH(aq) ---> Na + (aq) + OH - (aq) NaOH is a strong base

11 BASESBASES CaO(s) + H 2 O(liq)  Ca(OH) 2 (aq) Metal oxides are bases CaO in water. Indicator shows solution is basic.

12 ACIDSACIDS Nonmetal oxides can be acids CO 2 (aq) + H 2 O(l)  H 2 CO 3 (aq) SO 3 (aq) + H 2 O(l)  H 2 SO 4 (aq) and can come from burning coal and oil.

13 Acid-Base Reactions The “driving force” = water. Net ionic equation OH - (aq) + H + (aq)  H 2 O(l) OH - (aq) + H + (aq)  H 2 O(l) This applies to ALL reactions of STRONG acids and bases.

14 EXCHANGE: Precipitation Reactions REACTIONS

15 IONIC COMPOUNDS Compounds in Aqueous Solution Most redox reactions are in water — aqueous solutions - and involve ionic compounds KMnO 4 in water K + (aq) + MnO 4 - (aq)

16 Insoluble products: Precipitation formation

17 Precipitation Reactions The “driving force”= solid. Pb(NO 3 ) 2 (aq) + 2 KI(aq)  2 KNO 3 (aq) + PbI 2 (s) Net ionic equation Pb 2+ (aq) + 2 I - (aq)  PbI 2 (s)

18 If one ion from the “Soluble Compound” list is present, the compound is water soluble. Water Solubility of Ionic Compounds

19 Net Ionic Equations Mg(s) + 2 HCl(aq)  H 2 (g) + MgCl 2 (aq) We really should write Mg(s) + 2 H + (aq) + 2 Cl - (aq)  H 2 (g) + Mg 2+ (aq) + 2 Cl - (aq) The two Cl - ions are SPECTATOR IONS — they do not participate. Could have used NO 3 -.

20 Net Ionic Equations Mg(s) + 2 HCl(aq) --> H 2 (g) + MgCl 2 (aq) Mg(s) + 2 H + (aq) + 2 Cl - (aq) ---> H 2 (g) + Mg 2+ (aq) + 2 Cl - (aq) We leave the spectator ions out — Mg(s) + 2 H + (aq) ---> H 2 (g) + Mg 2+ (aq) NET IONIC EQUATION to give the NET IONIC EQUATION