Aqueous Reactions Pb(NO 3 ) 2 (s) + H 2 O (l)  leadnitrate(II) KI (s) potassiumiodide + H 2 O (l)  Pb 2+ (aq) + 2 NO 3 - (aq)+ K + (aq) + I - (aq)  yellow solid+ solution PbI 2 KNO 3 Pb 2+ (aq)+ NO 3 - (aq)2 K + (aq)+ I - (aq) displacement reaction solubility of salts

Solubility rules 1. Most NO 3 - salts are soluble 2. Most salts of alkali metals (IA) and NH 4 + are soluble 3. Most Cl -, Br - and I - salts are soluble Exceptions: Ag +, Pb 2+ and Hg 2 2+ insoluble 4. Most SO 4 2- are soluble Exceptions: Ca 2+, Ba 2+, Pb 2+, Hg 2 2+ insoluble 5. Most OH - are insoluble Exceptions: IA, Ca 2+, Ba 2+, Sr 2+ soluble 6. Most S 2-, CO 3 2-, CrO 4 2-, PO 4 3- insoluble Exceptions: IA, NH 4 + soluble

Pb 2+ (aq) + 2 NO 3 - (aq)+ K + (aq) + I - (aq) yellow solid+ solution PbI 2 KNO 3 2. Most IA salts are soluble PbI 2 (s) + K + (aq)+ NO 3 - (aq) balance the equation start with molecular equation 3. Most Cl -, Br - and I - salts are soluble Exceptions: Ag +, Pb 2+ and Hg 2 2+ insoluble 1. Most NO 3 - salts are soluble

Pb(NO 3 ) 2 (aq)+ KI (aq) balance molecular equation  PbI 2 (s) + KNO 3 (aq)2 2 change to ionic equation 1. Most NO 3 2- salts are soluble Pb 2+ (aq)+2NO 3 - (aq) 2. Most Group I salts are soluble 3. Most Cl -, Br - and I - salts are soluble except Ag +, Pb 2+ and Hg K + (aq)+2I - (aq)PbI 2 (s) +2K + (aq) +2NO 3 - (aq) spectator ionsthey can be cancelled out in net ionic equation Pb 2+ (aq)+ 2 I - (aq)  PbI 2 (s)

Acid/Base reactions HCl strongdissociates completely NaOHdissociates completelystrong H + (aq) Cl - (aq) Na + (aq)OH - (aq) H + (aq) H 2 O (l) +Cl - (aq)+ Na + (aq)+ OH - (aq) acid base  + Na + (aq) + Cl - (aq) HCl(aq) molecular eqn + NaOH(aq)  H 2 O(l) + NaCl(aq) ionic eqn H+H+ +Cl - + Na + + OH -  H2OH2O + Na + + Cl - net ionic eqn H+H+ + OH -  H2OH2O

Acid/Base reactions HCl strongdissociates completely H + (aq) Cl - (aq) acid Mg(OH) 2 does not dissociate completely Mg(OH) 2 (aq) weak base H+H+ + Cl -  Mg 2+ (aq)+ 2OH - (aq) + Mg(OH) 2 + Mg OH -  H2OH2O+ MgCl 2 molecular eqn ionic eqn net ionic eqn Mg(OH) 2 + HCl  H2OH2O+ Mg 2+ + Cl Mg(OH) 2 + 2H + + 2Cl -  2 H 2 O+ Mg 2+ +2Cl - Mg(OH) 2 (s) +2 H + (aq)  2 H 2 O(l)+ Mg 2+ (aq)

Acid/Base reactions neutralization reactions products are notacids bases H+H+ OH - equivalence point[H+][H+] = [OH - ] mol H + L = mol OH - L What volume of M HCl is needed to neutralize mL of M NaOH mol NaOH L x L= 8.75 x mol NaOH 8.75 x mol HCl mol HCl L = L= 87.5 mL HCl H2OH2O (x)(x)(x)(x)

A 2.2 g sample of an unknown acid, HA, is dissolved in 1.0 L of water. A titration required 25.0 mL of M NaOH to react completely. What is the molecular weight of the unknown? g HA2.2 g HA mol H + = mol OH mol NaOH = mol OH mol H + = 2.2 g mol = 176 g/mol mol HA = mol H L L