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Chapter 9 Acids and Bases

Chapter 9 Acids and Bases

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Chapter 9 Acids and Bases

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  1. Chapter 9Acids and Bases Acids and Bases

  2. Acids and Bases – What they do in water • Acids produce H+ in aqueous solutions water HCl H+(aq) + Cl- (aq) • Bases produce OH- in aqueous solutions water NaOH Na+(aq) + OH- (aq)

  3. Acids • Produce H+ (as H3O+) ions in water • Produce a negative ion (-) too • Taste sour • Corrode metals • React with bases to form salts and water

  4. Bases • Produce OH- ions in water • Taste bitter, chalky • Are electrolytes • Feel soapy, slippery • React with acids to form salts and water

  5. Learning Check AB1 Describe the solution in each of the following as: 1) acid 2) base or 3)neutral. A. ___soda B. ___soap C. ___coffee D. ___ wine E. ___ water F. ___ grapefruit

  6. Solution AB1 Describe each solution as: 1) acid 2) base or 3) neutral. A. _1_ soda B. _2_ soap C. _1_ coffee D. _1_ wine E. _3_ water F. _1_ grapefruit

  7. Learning Check AB2 Identify each as characteristic of an A) acid or B) base ____ 1. Sour taste ____ 2. Produces OH- in aqueous solutions ____ 3. Chalky taste ____ 4. Is an electrolyte ____ 5. Produces H+ in aqueous solutions

  8. Solution AB2 Identify each as a characteristic of an A) acid or B) base _A_ 1. Sour taste _B_ 2. Produces OH- in aqueous solutions _B_ 3. Chalky taste A, B4. Is an electrolyte _A_ 5. Produces H+ in aqueous solutions

  9. Some Common Acids HCl hydrochloric acid HNO3 nitric acid H3PO4 phosphoric acid H2SO4 sulfuric acid CH3COOH acetic acid

  10. Learning Check AB3 Give the names of the following A. HBr (aq) 1. bromic acid 2. bromous acid 3. hydrobromic acid B. H2CO3 1. carbonic acid 2. hydrocarbonic acid 3. carbonous acid

  11. Solution AB3 A. HBr 3. hydrobromic acid The name of a nonoxy acid begins with the prefix hydro- and ends with -ic acid. In a nonoxy acid, the negative anion end in -ide. B.H2CO3 1. carbonic acid The name of an oxyacid is named with the stem of the anion (carbonate) changed to -ic acid

  12. Some Common Bases NaOH sodium hydroxide KOH potassium hydroxide Ba(OH)2 ________________________ Mg(OH)2________________________ Al(OH)3 aluminum hydroxide

  13. Learning Check AB4 Match the formulas with the names: A. ___ HNO21)hydrochloric acid B. ___ Ca(OH)2 2) sulfuric acid C. ___ H2SO4 3) sodium hydroxide D. ___ HCl 4) nitrous acid E. ___ NaOH 5) calcium hydroxide

  14. Solution AB4 Match the formulas with the names: A. _4__ HNO21)hydrochloric acid B. _5__ Ca(OH)2 2) sulfuric acid C. _2__ H2SO4 3) sodium hydroxide D. _1__ HCl 4) nitrous acid E. _3__ NaOH 5) calcium hydroxide

  15. Learning Check AB5 Acid, Base Name or Salt CaCl2 ______ _________________ KOH ______ _________________ Ba(OH)2 ______ _________________ HBr ______ _________________ H2SO4 ______ __________________

  16. Solution AB5 Acid, Base Name or Salt CaCl2 salt calcium chloride KOH base potassiuim hydroxide Ba(OH)2 base barium hydroxide HBr acid hydrobromic acid H2SO4 acid sulfuric acid

  17. Acids & Bases –What they do with H+ Acids are hydrogen ion (H+) donors Bases are hydrogen ion (H+) acceptors HCl + H2O H3O+ + Cl- donor acceptor + - + +

  18. Neutralization Reactions When acid and bases with equal amounts of hydrogen ion H+ and hydroxide ions OH- are mixed, the resulting solution is neutral. NaOH (aq) + HCl(aq) NaCl + H2O base acid salt water Ca(OH)2 + 2 HCl CaCl2 + 2H2O base acid salt water

  19. Neutralization H3O+ and OH- combine to produce water H3O+ + OH- 2 H2O from acid from base neutral Net ionic equation: H+ + OH- H2O

  20. Ionization of Water Occasionally, in water, a H+ is transferred between H2O molecules . . . . . . . . H:O: + :O:H H:O:H + + :O:H- . . . . . . . . HH H water molecules hydronium hydroxide ion (+)ion (-)

  21. Pure Water is Neutral Pure water contains small, but equal amounts of ions: H3O+ and OH- H2O + H2O H3O+ + OH- hydronium hydroxide ion ion 1 x 10-7 M1 x 10-7 M H3O+ OH-

  22. Ion Product of Water Kw [ ] = Molar concentration Kw = [ H3O+ ] [ OH- ] = [ 1 x 10-7 ][ 1 x 10-7 ] = 1 x 10-14

  23. Acids • Increase H+ • HCl (g) + H2O (l)H3O+(aq) + Cl-(aq) • More [H3O+] than water > 1 x 10-7M • As H3O+ increases, OH- decreases [H3O+] > [OH-] H3O+ OH-

  24. Bases • Increase the hydroxide ions (OH-) H2O • NaOH (s) Na+(aq) + OH- (aq) • More [OH-] than water, [OH-] > 1 x 10-7M • When OH- increases, H3O+ decreases [OH] > [H3O+] OH- H3O+

  25. pH • Indicates the acidity [H3O+] of the solution • pH = - log [H3O+] • From the French pouvoir hydrogene (“hydrogen power” or power of hydrogen)

  26. Concentration changes by powers of 10 pH =1 has 10x more than pH = 2 pH = 1 has 100x more than pH = 3 More  Less 1 2 3 4 5 6 7 8 9 10 11 12 13 14

  27. pH In the expression for [H3O+] 1 x 10-exponent the exponent = pH [H3O+] = 1 x 10-pH M

  28. pH Range 0 1 2 3 4 5 6 7 8 910 11 12 13 14 Neutral [H+]>[OH-][H+] = [OH-][OH-]>[H+] Acidic Basic

  29. Some [H3O+] and pH [H3O+] pH 1 x 10-5 M 5 1 x 10-9 M 9 1 x 10-11M 11

  30. The pH Scale 1 1 2 2 3 3 4 4 5 5 6 6 7 8 9 9 10 10 11 11 12 12 13 14 Strong Acid Weak Acid Neutral Weak Alkali Strong Alkali

  31. Detecting Acids and Bases • You can detect an acid using an indicator. • INDICATOR- A substance that changes color in the presence of an acid or a base.

  32. INDICATORS • Litmus paper is an indicator • An acid turns blue litmus paper red • A base turns red litmus paperblue • Cabbage juice can be used as an indicator

  33. There are several ways to test pH • Blue litmus paper (red = acid) • Red litmus paper (blue = basic) • pH paper (multi-colored) • pH meter (7 is neutral, <7 acid, >7 base) • Universal indicator (multi-colored) • Indicators like phenolphthalein • Natural indicators like red cabbage, radishes