Acids & Bases

1. Acids & Bases

2. Text book • Section 8.2A • Sections 16.1 & 16.2

3. Self-ionization of water(Autoionization)

4. TruthH2O + H2O  H3O+ + OH-Convenient LieH2O  H+ + OH-

6. H3O+ = hydronium ionH+ = hydrogen ionOH- = hydroxide ion

12. P H E N O L P H T H A L E I N acid base Page 583

13. Acids react with active metals to produce hydrogen gas.(Page 264)M + HA  MA + H2Example: Zn + 2 HCl  ZnCl2 + H2(A single replacement reaction)

14. Saltcation plus the anion of an acid

15. Acids react with active metals to produce hydrogen gas.M + HA  MA + H2Example: Zn + 2 HCl  ZnCl2 + H2Ionic: Zn + 2H+  Zn2+ + H2

16. Acids react with carbonates and hydrogen carbonates to produce carbon dioxide and water. (Page 264)

17. HA + MCO3 MA +CO2 + H2OExample:2 HCl + CaCO3  CaCl2 + CO2 + H2O

18. What’s really happening?2 HCl + CaCO3  CaCl2 + H2CO3A double replacement reaction.

19. BUTH2CO3 isn’t stable at room temperature and pressure. It spontaneously decomposes:H2CO3  H2O + CO2

20. So……2 HCl + CaCO3  CaCl2 + CO2 + H20Ionic: 2 H+ + CaCO3  Ca2+ + CO2 + H20

21. HA + MHCO3  MA + CO2 + H2O EX: HC2H3O2 + NaHCO3 NaC2H3O2 + CO2 + H2OIonic: HC2H3O2+ HCO3-  C2H3O2- +CO2 + H2O

22. Homework Predict the products and write complete balanced reactions. • Mg(s) + HBr(aq) → • Al(s) + HNO3(aq) → • H2SO4(aq) + K2CO3(aq) → • MgCO3(s) + HClO4(aq) →

26. Definitions • monoprotic – can donate one proton (HA, EX: HCl) • diprotic – can donate two protons (H2A, EX: H2SO4) • triprotic – can donate three protons (H3A, EX: H3PO4) • polyprotic – diprotic and triprotic

27. Electrolyte formation: AcidsTruthHA + H2O  H3O+ + A-Convenient LieHA  H+ + A-Ionization

28. Electrolyte formation: AcidsSee page 563TruthHCl + H2O → H3O+ + Cl-Convenient LieHCl → H+ + Cl-Ionization

29. Acid Strength • Strong acids ionize completely. • Weak acids do not ionize completely. • See solubility rules for list of strong acids. • Figure 16.1 on page 567

30. Electrolyte formation: BaseCation(OH)  Cation+ + OH-Ex: Ca(OH)2  Ca2+ + 2 OH-(dissociation)

31. Electrolyte formation: BaseCation(OH)  Cation+ + OH-Ex: Ca(OH)2  Ca2+ + 2 OH-(dissociation)B + H2O  BH+ + OH-(B = base, BH+ = protonated base)Ex: NH3 + H2O  NH4+ + OH-(ionization)

32. Base Strength • Strong bases are hydroxide compounds that dissociate completely. • See solubility rules for a list of strong bases. • Weak bases are other hydroxide compounds (they don’t dissolve significantly into cations and hydroxide) AND all molecular bases (EX: NH3)

33. Concentration -v- Strength • These two concepts have nothing to do with each other. • An acid/base can be dilute and strong (Ex: 0.01M HCl) • An acid/base can be concentrated and weak (Ex: 8M H2SO3)

34. Homework • Page 273, #20 (Truth and convenient lie) • Page 273, #21

35. Arrhenius neutralization:acid + base  water + saltHBr + NaOH H2O + NaBrIonic: H+ + OH-  H2O

36. Homework • Page 273, #22 & 23

37. BronstedNeutralizationacid + base  protonated base + anionHA + B  BH+ + A-

38. BronstedNeutralizationHA + B  BH+ + A-HCl + NH3  NH4+ + Cl-Ionic: H+ + NH3  NH4+

39. Bronsted conjugates(Page 563) • Acid: HA  Conjugate base: A- • Base: B  Conjugate acid: HB+

40. So……An acid loses proton to become a conjugate base (ready to accept a proton)

41. And…..A base gains a proton to become a conjugate acid (ready to lose a proton)

42. Acid-base reaction • One substance donates a proton • One substance accepts a proton

43. Page 564 • Example 16.1 & 16.2 • Practice 16.2 • Homework: Page 572, Section Review #1-5

44. Relative strength • See page 567. • Strong acid  weak conjugate base • Weak acid  strong conjugate base • Strong base  weak conjugate acid • Weak base  strong conjugate acid

45. Homework • Page 589, #13-16

46. Water can accept or donate a proton(Recall autoionization.) amphoteric or amphiprotic

47. Examples:HCl + H2O  H3O+ + Cl-NH3 + H2ONH4+ + OH-

48. HCl + H2O  H3O+ + Cl-acid base ca cbNH3 + H2ONH4+ + OH-base acid ca cb

49. Lewis definition • Acid = electron pair acceptor • Base = electron pair donor