1. Chapter 20 Acids and Bases Describing Acids and Bases Hydrogen Ions and Acidity Acid-Base Theories Strengths of Acids and Bases

2. List as many properties of acids and bases as you can remember: Properties of Acids Properties of Bases

3. Determine if the following are acids or bases:

5. Lime

8. Vitamin C

18. DO NOT MIX

19. Ch 20.1 Describing Acids and Bases Properties of Acids and Bases Names and Formulas of Acids and Bases

20. Properties of Acids Corrosive ('burns' your skin) Sour taste (e.g. lemons, vinegar) Contains hydrogen ions (H + ) when dissolved in water Has a pH less than 7 Turns blue litmus paper to a red color Reacts with bases to form salt and water Reacts with metals to form hydrogen gas Reacts with carbonates to form carbon dioxide, water and a salt

22. Hydrofluoric Acid Burns

23. Properties of Bases Corrosive ('burns' your skin) Soapy feel Has a pH more than 7 Turns red litmus paper to a blue color Many alkalis (soluble bases) contain hydroxyl ions (OH - ) Reacts with acids to form salt and water

24. Sodium Hydroxide Burn

25. Names and Formulas of Acids Anion Ending ExampleAcid NameExample -ideCl - Hydro-(stem)-ic acidHydrochloric Acid -iteSO 3 2- (stem) – ous acidSulfurous Acid -ateNO 3 - (stem) –ic acidNitric Acid

26. Names and Formulas of Bases No Change Name the cation then the anion NaOH Sodium Hydroxide

27. Ch 20.2 Hydrogen Ions and Acidity Hydrogen Ions From Water The pH Concept Calculating pH Values Measuring pH

28. Hydrogen Ions From Water During the collisions of water molecules, occasionally a hydrogen ion from one molecule is transferred to another H 2 O + H 2 O  H 3 O + + HO - This forms a hyrdronium ion and a hydroxide ion. Self Ionization

29. Hydrogen Ions Names: Protons Hydrogen Ions Hydronium Ions Solvated Protons H + or H 3 O +

30. Neutral Solution The [ H + ] equals [ OH - ]

31. Ion Product Constant for Water (K w ) K w = [ H + ] [ OH - ] = 1.0x10 -14 M 2

32. Types of Solution Acidic Solution - [ H + ] greater [ OH - ] Basic Solution - [ H + ] less [ OH - ] Alkaline Solutions

33. The pH Concept pH is a simpler way of writing [ H + ] pH = -log [ H + ]

35. pH + pOH = 14

37. Arrhenius Acids and Bases 1887 Svante Arrhenius Acids – hydrogen containing compounds that ionize to yield hydrogen ions in aqueous solutions Bases - hydroxide containing compounds that ionize to yield hydroxide ions in aqueous solutions

38. Arrhenius Acids and Bases Monoprotic Acids – contain one ionizable hydrogen HNO 3 Diprotic Acids - contain two ionizable hydrogens H 2 SO 4 Triprotic Acids - contain three ionizable hydrogens H 3 PO 4

39. Arrhenius Acids and Bases Not all hydrogen's form ions Only those in very polar bonds HCl CH 4

40. Bronsted-Lowry Acids and Bases 1923 Johannes Bronsted and Thomas Lowry (independent of each other) Acid – Hydrogen ion donor (proton donor) Base – Hydrogen ion acceptor (proton acceptor)

41. Conjugate’s Conjugate Acid - Particle formed when a base gains a hydrogen ion Conjugate Base - Particle formed when an acid has donated a hydrogen ion HCl + H 2 O = H 3 O + + Cl - Acid Base Conjugate Acid Conjugate Base

42. Lewis Acids and Bases Gilbert Lewis (1875-1946) Lewis Acid – Substance that can accept a pair of electrons to form a covalent bond Lewis Base - Substance that can donate a pair of electrons to form a covalent bond

43. Strengths of Acids and Bases Strong and Weak Acids and Bases Calculating Dissociation Constants

44. Strong and Weak Acids and Bases Strong Acid – completely ionized in aqueous solutions Weak Acid – ionize only slightly in aqueous solutions

45. Acid Dissociation Constant K a The ratio of the concentration of the dissociated form of an acid to the concentration of the undissociated form CH 3 COOH (aq) + H 2 O (l) = H 3 O + (aq) + CH 3 COO - (aq) K a = [H + ] [CH 3 COO - ] [CH 3 COOH]

46. Acid Dissociation Constant K a Small K a = weak acid 1.8 x 10 -5 Large K a = strong acid 4.4 x 10 -4

47. Acid Dissociation Constant K a Diprotic and Triprotic acids lose their hydrogens one at a time, resulting in more than one K a H 3 PO 4 7.5 x 10 –3 6.2 x 10 –8 4.8 x 10 –13

48. Bases Strong Base – dissociate completely into metal ions and hydroxide ions in aqueous solutions Weak Base – form the hydroxide ion and the conjugate acid of the base NH 3(aq) + H 2 O (l) = NH 4 + (aq) + OH - (aq) K b = [NH 4 + ] [OH - ] [NH 3 ]

49. Base Dissociation Constant K b K b = [conjugate acid] [OH - ] [conjugate base] Small K b = weak base Large K b = strong base