1. Definitions

2. Arrhenius Acids and Bases Acids release hydrogen ions in water. Bases release hydroxide ions in water. An acid is a substance that produces hydronium ions, H 3 O +, when dissolved in water. Lewis Definitions A Lewis acid is a substance than can accept (and share) an electron pair. A Lewis base is a substance than can donate (and share) an electron pair. Lewis Acid Brønsted-Lowry Definitions A Brønsted-Lowry acid is a proton donor; it donates a hydrogen ion, H +. A Brønsted-Lowry base is a proton acceptor; it accepts a hydrogen ion, H +. Brønsted-Lowry Arrhenius acids Acid Definitions

3. Lewis acids Brønsted-Lowry Arrhenius acids The Arrhenius model of acids and bases was broadened by the Brønsted-Lowry model. The Lewis acid-base model is the most general in scope. The Lewis definition of an acid includes any substance that is an electron pair acceptor; a Lewis base is any substance that can act as an electron pair donor. Ralph A. Burns, Fundamentals of Chemistry 1999, page 483

4. Lewis acids Brønsted-Lowry Arrhenius acids The Arrhenius model of acids and bases was broadened by the Brønsted-Lowry model. The Lewis acid-base model is the most general in scope. The Lewis definition of an acid includes any substance that is an electron pair acceptor; a Lewis base is any substance that can act as an electron pair donor. Ralph A. Burns, Fundamentals of Chemistry 1999, page 483 Acid Definitions

5. Acid – Base Systems TypeAcidBase ArrheniusH + or H 3 O + producer OH - producer Brønsted- Lowry Proton (H + ) donor Proton (H + ) acceptor LewisElectron-pair acceptor Electron-pair donor

6. Arrhenius Acid 1+ ++ hydronium ion H3O+H3O+ 1- chloride ion Cl - water H2OH2O hydrogen chloride HCl (an Arrhenius acid) Any substance that releases H + ions as the only positive ion in the aqueous solution.

7. Definitions  Arrhenius - In aqueous solution… HCl + H 2 O  H 3 O + + Cl – AcidsAcids form hydronium ions (H 3 O + ) H HHHH H Cl OO – + acid Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

8. Definitions  Arrhenius - In aqueous solution… BasesBases form hydroxide ions (OH - ) NH 3 + H 2 O  NH 4 + + OH - H H H H H H N NO O – + H H H H base Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

9. Arrhenius Bases and Their Properties According to the definition of Arrhenius a: Base Base - "a substance whose water solution yields... Are NaOH and NH 3 considered to be Arrhenius bases? 1) Bases are electroytes Dissociation equation for NH 3 NH 3 (g) + H 2 O(l) NH 4 1+ (aq) + OH 1- (aq) Dissociation equation for NaOH NaOH(s) Na 1+ (aq) + OH 1- (aq) indicators 2) Bases cause indicators to turn a characteristic color 3) Bases neutralize acids NaOH(aq) + HCl(aq) NaCl(aq) + H 2 O(l) YES 4) Water solutions of bases tasted bitter and feel slippery. hydroxide ions (OH - ) as the only negative ions."

10. Neutralization Neutralization Neutralization is a chemical reaction between an acid and a base to produce a salt (an ionic compound) and water. NaOH(aq) + HCl(aq) NaCl(aq) + H 2 O(l) baseacidsaltwater Some neutralization reactions: H 2 SO 4 (aq) + NaOH(aq) Na 2 SO 4 +HOH sulfuric acidsodium hydroxidesodium sulfatewater HC 2 H 3 O 2 (aq) + Ca(OH) 2 (aq) Ca(C 2 H 3 O 2 ) 2 +HOH acetic acidcalcium hydroxidecalcium acetatewater 2 2 2 2

11. Neutralization ACID + BASE  SALT + WATER HCl + NaOH  NaCl + H 2 O HC 2 H 3 O 2 + NaOH  NaC 2 H 3 O 2 + H 2 O Salts can be neutral, acidic, or basic. Neutralization does not mean pH = 7. weak strong neutral basic Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

12. ACID + BASE  SALT + WATER HCl + NaOH  NaCl + H 2 O HC 2 H 3 O 2 + NaOH  NaC 2 H 3 O 2 + H 2 O Salts can be neutral, acidic, or basic. Neutralization does not mean pH = 7. weak strong neutral basic Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

13. Salts Salts Salts - Ionic compounds containing a positive ion other than the hydrogen ion and a negative ion other than the hydroxide ion. i.e., a metal and a non-metal Under what conditions do salts conduct current? NaCl(s) + H 2 O(l) Na 1+ (aq) + Cl 1- (aq) Formulas and names of common salts SALTFORMULACommon Name sodium chlorideNaCl(table) salt sodium nitrateNaNO 3 Chile saltpeter sodium bicarbonateNaHCO 3 baking soda potassium carbonateK 2 CO 3 potash ammonium chlorideNH 4 Clsal ammoniac NaCl

14. Salt Formation NaOH HCl strong base strong acid salt of a strong base and a strong acid NaCl NaOH HC 2 H 3 O 2 strong base weak acid salt of a strong base and a weak acid NaC2H3O2C2H3O2 Note: that in each case H-OH (water) is formed NaOH + HCl  NaCl + H 2 O NaOH + HC 2 H 3 O 2  NaC 2 H 3 O 2 + H 2 O

15. Salt Formation NH 3 H 2 SO 4 weak base strong acid salt of a weak base and a strong acid (NH 4 ) 2 SO 4 NH 3 HC 2 H 3 O 2 weak base weak acid salt of a weak base and a weak acid NH 4 C2H3O2C2H3O2 Note: that in each case H-OH (water) is also formed NH 4 OH H 2 SO 4 NH 4 OH + H 2 SO 4  (NH 4 ) 2 SO 4 + H 2 O NH 4 OH + HC 2 H 3 O 2  NH 4 C 2 H 3 O 2 + H 2 O

16. NH 3 H 2 SO 4 weak base strong acid salt of a weak base and a strong acid (NH 4 ) 2 SO 4 NH 4 OH H 2 SO 4 ammonium ion NH 4 + hydroxide ion OH - 1+ 1- NH 4 + OH - 1+ 1- sulfuric acid (NH 4 ) 2 SO 4 HOH 1+ HOH 1+ sulfate ion 2 NH 4 OH + H 2 SO 4 (NH 4 ) 2 SO 4 + 2 HOH water ammonium sulfate 2- H 2 SO 4 2 NH 4 OH + H 2 SO 4 (NH 4 ) 2 SO 4 + 2 H 2 O

17. phosphoric acid ammonium hydroxide ammonium phosphate Reactions that produce salt acid + base salt +water H 3 PO 4 NH 4 OH (NH 4 ) 3 PO 4 H2OH2O nitric acid magnesium hydroxide magnesium nitrate HNO 3 Mg(OH) 2 Mg(NO 3 ) 2 H2OH2O carbonic acid potassium hydroxide potassium carbonate H 2 CO 3 KOH K 2 CO 3 H2OH2O acetic acid aluminum hydroxide aluminum acetate HC 2 H 3 O 2 Al(OH) 3 Al(C 2 H 3 O 2 ) 3 H2OH2O perchloric acid barium hydroxide barium perchlorate HClO 4 Ba(OH) 2 Ba(ClO 4 ) 2 H2OH2O + + and yieldsand water

18. Brønsted-Lowry Acids and Bases 1+ + hydronium ion H3O+H3O+ 1- chloride ion Cl - (base) H2OH2O (acid) HCl ++ -- Acid = any substance that donates a proton. Base = any substance that accepts a proton.

19. Brønsted-Lowry Acids and Bases 1+ + hydronium ion H3O+H3O+ 1- chloride ion Cl - (base) H2OH2O (acid) HCl ++ -- Acid = any substance that donates a proton. Base = any substance that accepts a proton.

20. Brønsted-Lowry Acids and Bases (acid) H2OH2O (base) NH 3 ++ -- 1+ + ammonium ion NH 4 + 1- hydroxide ion OH -

21. Brønsted-Lowry Acids and Bases (acid) H2OH2O (base) NH 3 ++ -- 1+ + ammonium ion NH 4 + 1- hydroxide ion OH -

22. Brønsted-Lowry Acids and Bases 1+ + ammonium ion NH 4 + 1- hydroxide ion OH - (acid) H2OH2O (base) NH 3 ++ --

23. Brønsted-Lowry Acids and Bases 1+ + ammonium ion NH 4 + 1- hydroxide ion OH - (acid) H2OH2O (base) NH 3 ++ --

24. Definitions  Brønsted-Lowry HCl + H 2 O  Cl – + H 3 O + AcidsAcids are proton (H + ) donors. BasesBases are proton (H + ) acceptors. conjugate acid conjugate base baseacid Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

25. Definitions H 2 O + HNO 3  H 3 O + + NO 3 – CBCAAB Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem H H O HO O O N Base Acid

26. Definitions - can be an acid or a base.  Amphoteric - can be an acid or a base. NH 3 + H 2 O  NH 4 + + OH - CACBBA Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem H H O H N Base Acid H H

27. Definitions F - H 2 PO 4 - H2OH2O HF H 3 PO 4 H 3 O +  Give the conjugate base for each of the following: - an acid with more than one H +  Polyprotic - an acid with more than one H + Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

28. Definitions Br - HSO 4 - CO 3 2- HBr H 2 SO 4 HCO 3 -  Give the conjugate acid for each of the following: Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

29. Definitions  Lewis AcidsAcids are electron pair acceptors. BasesBases are electron pair donors. Lewis base Lewis acid Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem