Chapter 15 Notes1 Chapter 15: Aqueous Equilibria: Acids and Bases 1. acid/base characteristics reactions (Arrhenius, Bronsted-Lowry, gas formation) hydronium ion polyprotic, amphiprotic acids conjugate pairs strong vs. weak acids/bases 2. water autoionization, K W, pH and pOH 3. measuring pH 4. pH of solutions of strong acids/bases (calculations) 5. weak acids equilibria & K a ; calculations (pH from K a and K a from pH); %ionization; polyprotic acids 6. weak bases calculations relationship to K a 7. salts reactions calculations

Chapter 15 Notes2 Chapter 15: Aqueous Equilibria: Acids and Bases 8. factors affecting acid/base strength 9. Lewis acids/bases 1. acids & bases: characteristics acids: rainwater, coffee, fruit, carbonated water, vinegar, stomach neutral: blood, tears, saliva, milk bases: ammonia, lime water, borax, baking soda, lye, soap

Chapter 15 Notes3 1. acids & bases: reactions 1. Arrhenius acid/base reaction: acid donates H 1+ and base donates OH 1- general reaction: acid+base  salt+water examples: HCl(aq)+NaOH(aq)  NaCl(aq)+H 2 O(l) HNO 3 (aq)+KOH(aq)  net ionic equation: what about NH 3 ? and Na 2 CO 3 ? both are bases - how to understand? 2. Bronsted-Lowry reaction: more general acid supplies H 1+ and base grabs H 1+ acid must have H 1+ to donate and base must have lone pair of e 1-

Chapter 15 Notes4 1. acids & bases: reactions 2. Bronsted-Lowry reaction: more general acid supplies H 1+ and base grabs H 1+ acid must have H 1+ to donate and base must have lone pair of e 1- examples: (identify the acid and base in each) CO 3 2- (aq)+HCl(aq)  HCO 3 1- (aq)+Cl 1- (aq) HSO 3 1- (aq)+H 2 O(l)  HBr(aq)+NH 3 (aq)  HNO 3 (aq)+CH 3 NH 2 (aq) 

Chapter 15 Notes5 1. acids & bases: reactions HCN & H 2 S: solubility in water low; gaseous HCN & H 2 S bubble out of sol’n at high concentrations H 2 CO 3 and H 2 SO 3 : decompose at high concentrations example: HCl(aq)+HS 1- (aq)  H 2 S(g)+Cl 1- HBr(aq)+CN 1- (aq)  HCO 3 1- (aq)+HNO 3 (aq)  H 2 CO 3 (aq)+NO 3 1- (aq)  H 2 O(l)+CO 2 (g) hydronium ion: H 3 O 1+ ; hydrated H 1+ [H(H 2 O) n 1+, where n=1,2,3...] polyprotic: can donate >1 H 1+ ; H 2 SO 4, H 2 CO 3, H 3 PO 4, H 2 S amphiprotic: can donate and accept H 1+ : H 2 O, HCO 3 1-, HS 1-, H 2 PO 4 -, HPO 4 2-,

Chapter 15 Notes6 1. acids & bases: conjugate pairs: acid/base pairs that differ by transfer of H 1+ examples- acid/base: H 2 O/OH 1- ; HC 2 H 3 O 2 /C 2 H 3 O 2 1- ; HCl/Cl 1- ; name the conjugate acid of: H 2 OHS 1- NO 3 1- Br 1- CH 3 NH 2 name the conjugate base of: H 3 O 1+ H 3 PO 4 CO 3 2- strong vs. weak strong: strong electrolyte, dissociates 100% in water in water, exists as: weak: weak electrolyte, dissociates <10% in water in water, exists as: driving force in acid/base reactions: 1. from strong to weak 2. strong acids, bases are dissociated, weak acids, bases are molecular

Chapter 15 Notes7

8 1. acids & bases: strong vs. weak example: predict the products, then predict whether the reaction goes left, right, or “can’t tell” HCl(aq)+NO 2 -1  Br 1- (aq)+NH 4 1+ (a q)  HC 2 H 3 O 2 (aq)+HS 1- (aq)  NO 3 1- (aq)+CH 3 NH 3 1+ (aq) 