Chapter 19: Acids And Bases

1. Chapter 19: Acids AndBases

2. Where can acids be found? Sodas Stomach Vinegar Citrus fruits Where can bases be found? Soap Drano Antacid tablets Windex detergent Class question

3. Properties of Acids • Taste sour • React with bases • Litmus paper test – turn blue litmus paper red • Electrolytic – conduct electricity

4. Properties of Bases • Taste bitter • Feels slippery • React with acids • Litmus paper test – turn red litmus paper blue • electrolytic

5. Nomenclature of Acids • Acids are composed of a(n) ________________ followed by a(n) _______ Hydrogen ion (H+) anion H+ + Cl1- HCl Ex: H+ + SO42- H2SO4

6. H+ + anion • H+ + anion with –ide ending  acid name is __________________ HCl anion? _______ acid name ________________ Hydro _____ic acid chloride Hydrochloric acid

7. H+ + anion • H+ + anion with –ide ending  acid name is __________________ HF anion? _______ acid name ________________ Hydro _____ic acid fluoride Hydrofluoric acid

8. H+ + anion • H+ + anion with –ate ending  acid name is __________________ HNO3 anion? _______ acid name ________________ _____ic acid nitrate nitric acid

9. H+ + anion • H+ + anion with –ate ending  acid name is __________________ H2SO4 anion? _______ acid name ________________ _____ic acid sulfate sulfuric acid

10. H+ + anion • H+ + anion with –ite ending  acid name is __________________ HNO2 anion? _______ acid name ________________ _____ous acid nitrite nitrous acid

11. H+ + anion • H+ + anion with –ite ending  acid name is __________________ HClO2 anion? _______ acid name ________________ _____ous acid chlorite chlorous acid

12. Writing acid formulas • Hydrobromic acid anion? ___________ formula ______ • Acetic acid anion? ___________ formula ______ • Nitrous acid anion? ___________ formula ______ HBr Bromide (Br1-) HC2H3O2 acetate(C2H3O21-) HNO2 nitrite (NO21-)

13. Nomenclature of Bases • Bases are composed of a(n) _______ followed by a(n) ________________ cation hydroxide (OH1-)

14. Writing Base Names • Rule: name the cation and add “hydroxide” • NaOH • Mg(OH)2 • Fe(OH)3 sodium hydroxide magnesium hydroxide Iron (III) hydroxide Memorize: NH3 = ammonia

15. Writing base formulas • potassium hydroxide cation? ______ formula ______ • Calcium hydroxide cation? ______ formula ______ • Aluminum hydroxide cation? ______ formula ______ KOH K+ Ca(OH)2 Ca2+ Al(OH)3 Al3+

16. Ions In Solution • Why are some solutions acidic, basic, or neutral? depends on number of H+ and OH- ions present

17. Ions In Solution • Acidic solution – contain more H+ ions than OH- ions 4000 H+ and 0 OH- is acidic 1000 H+ and 500 OH- is acidic 5 H+ and 3 OH- is acidic

18. Ions In Solution • Basic Solution – contain more OH- ions than H+ ions 4000 OH- and 0 H+ is basic 1000 OH- and 500 H+ is basic 5 OH- and 3 H+ is basic

19. Ions In Solution • Neutral Solution – equal amounts of H+ and OH- ions 4000 OH- and 4000 H+ is neutral 1000 OH- and 1000 H+ is neutral 5 OH- and 5 H+ is neutral

20. Self Ionization of Water • simplified version H2O  H+ + OH-

21. Types of Acids/Bases • Arrhenius Model • Bronsted-Lowry Model

22. Arrhenius Model of Acids and Bases • Arrhenius Acids • Defn: contain H+ and ionizes to form H+ • Examples HCl  HNO3  makes solution ACIDIC H+ + Cl- H+ + NO3-

23. Arrhenius Model of Acids and Bases • Arrhenius Bases • Defn: • contain OH- and ionizes to produce OH- ions • Examples NaOH  Ca(OH)2  makes solution BASIC Na+ + OH- Ca2+ + 2 OH-

24. Bronsted-Lowry Model • Bronsted-Lowry Acid • Defn: proton/H+donor • can give H+ to another species • Bronsted-Lowry Base • Defn: proton/H+acceptor • can take H+ from another species

25. Bronsted-Lowry Model • REMEMBER!!!! REMEMBER!!!! acids donate, bases accept protons Ashley does boys always

26. Bronsted-Lowry Model • Examples HCl + H2O  Cl- + H3O+ What is happening here? Acid (donates proton) Base (accepts proton) Which is the acid? base?

27. Bronsted-Lowry Model • Examples NH3 + H2O  NH4+ + OH- What is happening here? Base (accepts proton) Acid (donates proton) Which is the acid? base?

28. Conjugate Acid/Base Pairs • Conjugate acid – new species produced when base gains H+ ion • Conjugate base – new species produced when acid donates H+ ion

29. Conjugate Acid/Base Pairs • general Bronsted-Lowry reaction acid + base  conj. acid + conj. base conj. acid/base pair conj. acid/base pair Every acid has a conjugate base. Every base has a conjugate acid.

30. Conjugate Acid/Base Pairs • Examples HNO3 + H2O  H3O+ + NO3- What is the acid? base? conj. acid/base pair C.A. C.B. acid base What is the conjugate acid/base? conj. acid/base pair

31. Conjugate Acid/Base Pairs • Examples NH3 + H2O  NH4+ + OH- What is the acid? base? conj. acid/base pair base acid C.A. C.B. What is the conjugate acid/base? conj. acid/base pair

32. Conjugate acid-base pairs • What is the conjugate base of: H2SO4 _________ H3O+ ________ • What is the conjugate acid of: HPO42- _________ OH1- ________ HSO41- H2O H2PO41- H2O How can H2O be both acid and base?

33. Amphoteric • Defn – substance that can act as both acids and bases HNO3 + H2O  H3O+ + NO3- NH3 + H2O  NH4+ + OH- Is H2O a base or acid? base Is H2O a base or acid? acid Water is amphoteric b/c it is acts as a base in one reaction and acts as an acid in the second

34. Mono-, Di-, Triprotic Acids • Defns • monoprotic (HA) – one ionizable proton ex: HF, HCl, HBr • diprotic (H2A) – two ionizable protons ex: H2SO4, H2CO3 • triprotic (H3A) – three ionizable protons ex: H3PO4, H3BO3

35. Polyprotic Acid Ionization • Always forms ONE H+ H3PO4 H2PO41- HPO42- H2PO41- + H+ HPO42- + H+ PO43- + H+

36. Strong Acid/Base • Defn – acid or base that completely ionizes HA H+ + A- XOH X+ + OH- 100% ionization 100% ionization • every single HA molecule ionizes into H+ and A-

37. Strong Acid • Illustration + + - H H A A + + - H H A A + + - H H A A All break into ions

38. 6 Strong Acids • HCl – hydrochloric acid • HBr – hydrobromic acid • HI – hydroiodic acid • HClO4 – perchloric acid • H2SO4 – sulfuric acid • HNO3 – nitric acid

39. Strong Bases • Group I and II metal hydroxides LiOH NaOH KOH RbOH Mg(OH)2 Ca(OH)2 Sr(OH)2 Ba(OH)2 No need to memorize exact ones

40. Weak Acid/Base • Defn – acid or base that partially ionizes HA H+ + A- XOH X+ + OH- partial ionization • not all will ionize;the weaker it is the less it ionizes

41. Weak Acid • Illustration + + - H H A A H H A A H H A A Only some break into ions

42. What are the weak acids and bases? • The ones that are NOT strong

43. Strong or weak, concentrated or diluted • For acids and bases, it is important to distinguish between concentrated and dilute from strong and weak. The words _________ and __________ have different meanings. Similarly, ___________ and ___________ are not the same either. strong concentrated weak dilute

44. Strong or weak, concentrated or diluted • Strong and weak refer to ____________________________ • Concentrated and dilute refer to ____________________________ how much substance ionizes how much solute is present

45. Example • 1 M HCl • 12 M HCl • 1 M H2CO3 • 12 M H2CO3 Strong and dilute Strong and concentrated weak and dilute weak and concentrated

46. Ion Product Constant for Water (Kw) • Defn: equilibrium value for self ionization of water (H2O  H+ + OH-) • Formula Kw = [H+][OH-] = 1 x 10-14 ALWAYS ALWAYS ALWAYS

47. Is solution acidic, basic, or neutral? • Acidic • Basic • neutral [H+] > [OH-] [H+] < [OH-] [H+] = [OH-]

48. pH and pOH • pH • Defn: pH = -log [H+] • Scale: range from 0 to 14 ACIDIC BASIC 0 7 14 pH (neutral)

49. pH c) change one pH unit  represents a ten fold change in strength - ex: pH = 3 vs pH = 4 pH 3 is 101 or 10 times more acidic - ex: pH = 7 vs pH = 10 pH 7 is 103 or 1000 times more acidic

50. pOH • Formula: -log [OH-]