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Chapter Four: TYPES OF CHEMICAL REACTIONS AND SOLUTION STOICHIOMETRY 講義.

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Presentation on theme: "Chapter Four: TYPES OF CHEMICAL REACTIONS AND SOLUTION STOICHIOMETRY 講義."— Presentation transcript:

1 Chapter Four: TYPES OF CHEMICAL REACTIONS AND SOLUTION STOICHIOMETRY 講義

2 Assignment for Chapter 4 12,20,27,35,47,57,63,75,83,95,107.

3 Core Materials Chemical reactions in solution are very important in everyday life. Water is a polar solvent that dissolves many ionic and polar substances. Electrolytes Acids and bases: Arrhenius model, BrØnsted-Lowry model. Molarity Types of equations that describe solution reactions: Formula equation; Complete ionic equation; Net ionic equation. Solubility rules Important types of solution reactions: Acid-base reactions; Precipitation reactions; Oxidation-reduction reactions. Titrations: Stoichiometric(equivalence)point;Endpoint: Oxidation-reduction reactions: Oxidation, Reduction,Oxidizing agent,Reducing agent.

4 Chemical Impact Arrhenius A Man with Solutions (p.132) Science is a human endeavor, subject to frailties and governed by personalities, politics, and prejudices. One of the best illustrations of the often bumpy path of The advancement of scientific knowledge is the story of Swedish chemist Svante Arrhenius. …… Such a setbakc could have ended his scientific career, but Arrhenius was a crusader; he was determined to see his theory thriumph. He promptly embarked on a political campaign, enlisted the aid of several prominent scientists, to get his theory accepted. Ultimately, the ionic theory triumphed. Arrhenius’ fame Spread, and honors heaped on him, culminating in the Nobel Prize in chemistry in Not one to rest on his laurels., Arrhenius turned to new fields, including astronomy, He formulated a new theory that the solar system may have Come into being through the collision of stars. His exceptional Versatility led him to study the use of serums to fight disease, Energy resources and conservation, and the origin of life.

5 Nature of Aqueous Solutions Solute – substance being dissolved Solvent – liquid water Electrolyte – substance that when dissolved in water produces a solution that can conduct electricity 4.2

6 Water, the Common Solvent One of the most important substances on earth Can dissolve many different substances A polar molecule 4.1

7 Water, the Common Solvent, with many uncommon properties One of the most important substances on earth Can dissolve many different substances A polar molecule 4.1 Lowest density at 4 o C, Ice is lighter than water, Large specific heat, Large vaporization and melting heats, ….

8 Figure 4.1 The Water Molecule

9 Figure 4.2 Polar Water Molecules Interact with the Positive and Negative Ions of a Salt Assisting in the Dissolving Process

10 Dissolution of a Solid in a Liquid 4.1

11 Water can also dissolve many non-ionic compounds

12 Figure 4.3a The Ethanol Molecule Contains a Polar O-H Bond Similar to Those in the Water Molecule

13 Figure 4.3b The Polar Water Molecule Interacts Strongly with the Polar-O-H bond in Ethanol

14 Figure 4.4a-c Electrical Conductivity of Aqueous Solutions

15 Figure 4.5 NaCl Dissolves

16 Figure 4.6 HCl is Completely Ionized

17 Figure 4.7 An Aqueous Solution of Sodium Hydroxide

18 Figure 4.8 Acetic Acid (HC 2 H 3 O 2 )

19 Figure 4.9 The Reaction of NH 3 in Water

20 Electrolytes Strong Electrolytes – conduct current very efficiently (bulb shines brightly) Weak Electrolytes – conduct only a small current (bulb glows dimly) Nonelectrolytes – no current flows (bulb remains unlit) 4.2

21 Electrolyte Behavior 4.2

22 Chemical Reactions of Solutions We must know: –Nature of the reaction –Amounts of chemicals present in the solutions 4.3

23 Molarity Molarity (M) = moles of solute per volume of solution in liters: 4.3

24 An Aqueous Solution of Co(NO 3 ) 2.

25 Concept Check Which of the following solutions contains the greatest number of ions? a) mL of 0.10 M NaCl. b) mL of 0.10 M CaCl 2. c) mL of 0.10 M FeCl 3. d) mL of 0.10 M sucrose. 4.3

26 Let’s Think About It Draw molecular level pictures showing each solution. Think about relative numbers of ions. How many moles of each ion are in each solution? 4.3

27 Notice The solution with the greatest number of ions is not necessarily the one in which: –the volume of the solution is the largest. –the formula unit has the greatest number of ions. 4.3

28 Dilution The process of adding water to a stock solution to achieve the molarity desired for a particular solution. Dilution with water does not alter the numbers of moles of solute present. Moles of solute before dilution = moles of solute after dilution M 1 V 1 = M 2 V 2 4.3

29 Types of Chemical Reactions Precipitation Reactions Acid-Base Reactions Oxidation-Reduction Reactions 4.4

30 Precipitation Reaction A double displacement reaction in which a solid forms and separates from the solution. –When ionic compounds dissolve in water, the resulting solution contains the separated ions –Precipitate – the solid that forms 4.5

31 Figure 4.17 Molecular-Level Representations Illustrating the Reaction of KCl (aq) with AgNO 3 (aq) to Form AgCl (s)

32 Precipitation of Silver Chloride KCl (aq) + AgNO 3 (aq)  AgCl (s) + K + (aq) +NO 3 – (aq) Cl – (aq) + Ag + (aq)  AgCl (s)

33 The Reaction of K 2 CrO 4 (aq) and Ba(NO 3 ) 2 (aq) 4.5 Ba 2+ (aq) + CrO 4 2– (aq) → BaCrO 4 (s) solid BaCrO 4 formed

34 Precipitates Soluble – solid dissolves in solution; (aq) is used in reaction Insoluble – solid does not dissolve in solution; (s) is used in reaction Insoluble and slightly soluble are often used interchangeably 4.5

35 Simple Rules for Solubility 1.Most nitrate (NO 3  ) salts are soluble. 2.Most alkali (group 1A) salts and NH 4 + are soluble. 3.Most Cl , Br , and I  salts are soluble (except Ag +, Pb 2+, Hg 2 2+ ). 4.Most sulfate salts are soluble (except BaSO 4, PbSO 4, Hg 2 SO 4, CaSO 4 ). 5.Most OH  salts are only slightly soluble (NaOH, KOH are soluble, Ba(OH) 2, Ca(OH) 2 are marginally soluble). 6.Most S 2 , CO 3 2 , CrO 4 2 , PO 4 3   salts are only slightly soluble. 4.5

36 Table 4.1 Simple Rules for the Solubility of Salts in Water

37 Describing Reactions in Solution Formula Equation (Molecular Equation) –Reactants and products as compounds AgNO 3 (aq) + NaCl(aq)  AgCl(s) + NaNO 3 (aq) Complete Ionic Equation –All strong electrolytes shown as ions Ag + (aq) + NO 3  (aq) + Na + (aq) + Cl  (aq)  AgCl(s) + Na + (aq) + NO 3  (aq) 4.6

38 Describing Reactions in Solution Net Ionic Equation –Show only components that actually react Ag + (aq) + Cl  (aq)  AgCl(s) –Na + and NO 3  are spectator ions 4.6

39 Concept Check You have two separate beakers with aqueous solutions, one with 4 “units” of potassium sulfate and one with 3 “units” of barium nitrate. a)Draw molecular level diagrams of both solutions. 4.6/4.7

40 Concept Check You have two separate beakers with aqueous solutions, one with 4 “units” of potassium sulfate and one with 3 “units” of barium nitrate. b)Draw a molecular level diagram of the mixture of the two solutions before a reaction has taken place. 4.6/4.7

41 Concept Check You have two separate beakers with aqueous solutions, one with 4 “units” of potassium sulfate and one with 3 “units” of barium nitrate. c)Draw a molecular level diagram of the product and solution formed after the reaction has taken place. 4.6/4.7

42 Solution Stoichiometry Problems Identify the species present in the combined solution. Write the balanced net ionic equation. Calculate the moles of reactants. Determine limiting reactant. Calculate the moles of product(s). Convert to grams or other units. 4.7

43 Determining the Mass of Product Formed

44

45 Acid-Base Reactions (Brønsted-Lowry) Acid – proton donor Base – proton acceptor For a strong acid and base reaction: H + (aq) + OH – (aq)  H 2 O(l) 4.8

46 Neutralization of a Strong Acid by a Strong Base 4.8

47 Performing Calculations for Acid-Base Reactions

48 Neutralization Reactions I

49 Neutralization Reactions II

50 Neutralization Titration

51 Key Titration Terms Titrant – solution of known concentration used in titration Analyte – substance being analyzed Equivalence point – enough titrant added to react exactly with the analyte Endpoint – the indicator changes color so you can tell the equivalence point has been reached 4.8

52 Performing Calculations for Acid-Base Reactions 1.List initial species and predict reaction. 2.Write balanced net ionic reaction. 3.Calculate moles of reactants. 4.Determine limiting reactant. 5.Calculate moles of required reactant or product. 6.Convert to grams or volume, as required. 4.8

53 Oxidation-Reduction Reactions (Redox Reactions) Reactions in which one or more electrons are transferred. 4.9

54 Reaction of Sodium and Chlorine 4.9

55 Oxidation of Copper Metal by Nitric Acid

56 Rules for Assigning Oxidation States 1.Oxidation state of an atom in an element = 0 2.Oxidation state of monatomic element = charge 3.Oxygen =  2 in covalent compounds (except in peroxides where it =  1) 4.Hydrogen = +1 in covalent compounds 5.Fluorine =  1 in compounds 6.Sum of oxidation states = 0 in compounds 7.Sum of oxidation states = charge of the ion 4.9

57 Table 4.2 Rules for Assigning Oxidation States

58 Exercise Find the oxidation states for each of the elements in each of the following compounds: K 2 Cr 2 O 7 CO 3 2- MnO 2 PCl 5 SF 4 4.9

59 Redox Characteristics Transfer of Electrons Transfer may occur to form ions Oxidation – increase in oxidation state (loss of electrons); reducing agent Reduction – decrease in oxidation state (gain of electrons); oxidizing agent 4.9

60 Figure 4.20 A Summary of Oxidation- Reduction Process

61 Concept Check Which of the following are oxidation-reduction reactions? Identify the oxidizing agent and the reducing agent. a)Zn(s) + 2HCl(aq)  ZnCl 2 (aq) + H 2 (g) b)Cr 2 O 7 2- (aq) + 2OH - (aq)  2CrO 4 2- (aq) + H 2 O(l) c)2CuCl(aq)  CuCl 2 (aq) + Cu(s) 4.9

62 Balancing Oxidation-Reduction Reactions Cr 2 O 7 2- (aq) + SO 3 2- (aq)  Cr 3+ (aq) + SO 4 2- (aq) How can we balance this equation? First Steps: –Separate into half-reactions –Balance elements except H and O 4.10

63 The Half-Reaction Method (Acidic Solution)

64 Method of Half Reactions Cr 2 O 7 2- (aq)  2Cr 3+ (aq) SO 3 2- (aq)  SO 4 2- (aq) How many electrons are involved in each half reaction? 4.10

65 Method of Half Reactions (continued) 6e - + Cr 2 O 7 2- (aq)  2Cr 3+ (aq) SO 3 2- (aq)  + SO 4 2- (aq) + 2e - How can we balance the oxygen atoms? 4.10

66 Method of Half Reactions (continued) 6e - + Cr 2 O 7 2- (aq)  Cr 3+ (aq) + 7H 2 O H 2 O +SO 3 2- (aq)  + SO 4 2- (aq) + 2e - How can we balance the hydrogen atoms? 4.10

67 Method of Half Reactions (continued) This reaction occurs in an acidic solution. 14H + + 6e - + Cr 2 O 7 2-  2Cr H 2 O H 2 O +SO 3 2-  SO e - + 2H + How can we balance the electrons? 4.10

68 Method of Half Reactions (continued) 14H + + 6e - + Cr 2 O 7 2-  2Cr H 2 O 3[H 2 O +SO 3 2-  SO e - + 2H + ] Final Balanced Equation: Cr 2 O SO H +  2Cr SO H 2 O 4.10

69 Exercise Balance the following oxidation-reduction reaction that occurs in acidic solution. Br - (aq) + MnO 4 - (aq)  Br 2 (l)+ Mn 2+ (aq) 4.10

70 Half-Reaction Method – Balancing in Base 1.Balance as in acid. 2.Add OH  that equals H + ions (both sides!) 3.Form water by combining H +, OH . Cancel any water molecules that appear on both sides. 4.Check elements and charges for balance. 4.10

71 For Review Chemical reactions in solution are very important in everyday life. Water is a polar solvent that dissolves many ionic and polar substances. Electrolytes ˙Strong electrolyte: 100% dissociated to produce separate ions; strongly conducts an electric current ˙Weak electrolyte: Only a small percentage of dissolved molecules produce ions; weakly conducts an electric current ˙Nonelectrolyte: Dissolved substance produces no ions; does not conduct an electric current Acids and bases ˙Arrhenius model: Acid: produces H+; Base: produces OH- ˙BrØnsted-Lowry model: Acid: proton donor; Base: proton acceptor ˙Strong acid: completely dissociates into separated H+ and anions ˙Weak acid: dissociates to a slight extent Molarity ˙One way to describe solution composition ˙Moles of solute after dilution=moles of solute before dilution Types of equations that describe solution reactions ˙Formula equation: all reactants and products are written as complete formulas ˙Complete ionic equation: all reactants and products that are strong electrolytes are written as separated ions ˙Net ionic equation: only those compounds that undergo a change are written; spectator ions are not included Solubility rules ˙Based on experiment observation ˙Help predict the outcomes of precipitation reactions

72 For Review ˙Important types of solution reactions Acid-base reactions: involve a transfer of H+ ions ˙Precipitation reactions: formation of a solid occurs ˙Oxidation-reduction reactions: involve electron transfer Titrations ˙Measures the volume of a standard solution (titrant) needed to react with a substance in solution ˙Stoichiometric(equivalence)point: the point at which the required amount of titrant has been added to exactly react with the substance being analyzed ˙Endpoint: the point at which a chemical indicator changes color Oxidation-reduction reactions ˙Oxidation states are assigned using a set of rules to keep track of electron flow ˙Oxidation: increase in oxidation state (a loss of electrons) ˙Reduction: decrease in oxidation state (a gain of electrons) ˙Oxidizing agent: gains electrons (is reduced) ˙Reducing agent: loses electrons (is oxidized) ˙Equaitons for oxidation—reduction reactions are usually balanced by the half-reaction method

73 Chapter Four Types of Chemical Reactions and Solution Stoichiometry 案例 / 討論

74 Figure 4.10a-c Steps Involved in the Preparation of a Standard Aqueous Solution

75 Figure 4.11a-b Measuring Pipets and Volumetric Pipets Measure Liquid Volume

76 Figure 4.12a-c A Measuring Pipet is Used to Add Acetic Solution to a Volumetric Flask

77 Figure 4.14 a&b Reactant Solutions

78 Figure 4.15 a&b The Reaction of K 2 CrO 4 and Ba(NO 3 ) 2

79 Figure 4.19 The Reaction of Solid Sodium and Gaseous Chlorine to Form Solid Sodium Chloride

80 Figure 4.20 A Summary of Oxidation- Reduction Process

81 The Half-Reaction Method (Acidic Solution)

82 Figure 4.4a-c Electrical Conductivity of Aqueous Solutions

83 The Half-Reaction Method (Basic Solution)

84 An Aqueous Solution of Co(NO 3 ) 2.

85 Figure 4.10 Steps Involved in the Preparation of a Standard Aqueous Solution

86 Figure 4.13 Yellow Aqueous Potassium

87 Figure 4.14a-b Reactant Solutions

88 Figure 4.15c Solution Post- Reaction

89 Figure 4.16 Addition of Silver Nitrate to Aqueous Solution of Potassium Chloride

90 Figure 4.17 Reaction of KCI(aq) with AgNO 3 (aq) to form AgCI(s).

91 Lead Sulfate

92 KOH and Fe(NO 3 ) 3 Mix to Create Solid Fe(OH) 3.

93 Figure 4.18a-c The Titration of an Acid with a Base

94 Figure 4.19 The Reaction of Solid Sodium and Gaseous Chlorine to Form Solid Sodium Chloride

95 Oxidation of Copper Metal by Nitric Acid

96 Magnetite

97 Aluminum and Iodine Mix to Form Aluminum Iodide

98 When Potassium Dichromate Reacts with Ethanol, the Solution Contains Cr 3+.

99 Table 4.1 Simple Rules for the Solubility of Salts in Water

100 Table 4.2 Rules for Assigning Oxidation States

101 Chapter Four Types of Chemical Reactions and Solution Stoichiometry 問答 / 練習

102 Question Which of the following solutions contains the greatest total ion concentration? –One mole of potassium chloride dissolved in 1.0 L of solution –One mole of iron(II) nitrate dissolved in 1.0 L of solution –One mole of potassium hydroxide dissolved in 1.0 L of solution –One mole of sodium phosphate dissolved in 1.0 L of solution

103 Answer d)One mole of sodium phosphate dissolved in 1.0 L of solution Section 4.2, The Nature of Aqueous Solutions: Strong and Weak Electrolytes All of the possible answers are strong electrolytes. The one that dissociates into the most ions [KCl into 2 mol ions, Fe(NO 3 ) 2 into 3 mol ions, KOH into 2 mol ions, Na 3 PO 4 into 4 mol ions] is the answer.

104 Question Which of the following statements is true? –If a substance is soluble, it must be an electrolyte. –If a substance is an electrolyte, it must be soluble. –Weak electrolytes must be less soluble than strong electrolytes. –Nonelectrolytes are nonsoluble.

105 Answer b)If a substance is an electrolyte, it must be soluble. Section 4.2, The Nature of Aqueous Solutions: Strong and Weak Electrolytes Electrolytes are substances that dissolve into ions. Not all soluble substances are electrolytes (such as table sugar).

106 Question Consider five solutions, each of which has the same mass of solute in mL of solution. Which has the highest concentration as measured in molarity? –KCl –NaCl –Na 2 SO 4 –NaF –CaCl 2

107 Answer d)NaF Section 4.3, The Composition of Solutions The highest concentration as measured in molarity for the same volume of solution will be determined by the solute with the smallest molar mass.

108 Question Which of the following solutions contains the greatest number of ions? –400.0 mL of 0.10 M NaCl –300.0 mL of 0.10 M CaCl 2 –200.0 mL of 0.10 M FeCl 3 –800.0 mL of 0.10 M sucrose

109 Answer b)300.0 mL of 0.10 M CaCl 2. Section 4.3, The Composition of Solutions The concentrations are all the same, so we must look at the volumes and the number of ions per compound. While each molecule of FeCl 3 dissolves into four ions, and each molecule of CaCl 2 dissolves into only three ions, the greater volume of the CaCl 2 solution more than makes up for this difference.

110 Question Lead(II) nitrate reacts with sodium chloride in aqueous solution to form a precipitate. What is the net ionic equation for this reaction? –Pb 2+ (aq) + 2NO 3 – (aq)  Pb(NO 3 ) 2 (s) –Na 2+ (aq) + Cl – (aq)  NaCl(s) –Pb 2+ (aq) + 2Cl – (aq)  PbCl 2 (s) –Na + (aq) + NO 3 – (aq)  NaNO 3 (s)

111 Answer c) Pb 2+ (aq) + 2Cl – (aq)  PbCl 2 (s) Section 4.5, Precipitation Reactions; Section 4.6, Describing Reactions in Solution Both of the reactants are strong electrolytes and completely break up into ions, but the product, lead(II) chloride, is a precipitate.

112 Question Aqueous solutions of sodium sulfide and copper(II) chloride are mixed together. Which statement is correct? –Both NaCl and CuS will precipitate from solution. –No precipitate will form. –Only CuS will precipitate from solution. –Only NaCl will precipitate from solution.

113 Answer c)Only CuS will precipitate from solution. Section 4.5, Precipitation Reactions Based on the simple rules for solubility of salts in water, sodium chloride will not form a precipitate while copper(II) sulfide will.

114 Question An aqueous solution of barium nitrate reacts with an aqueous solution of sodium sulfate. Identify the solid and indicate its coefficient in the balanced equation. –NaNO 3 ; 1 –BaSO 4 ; 1 –NaNO 3 ; 2 –BaSO 4 ; 2 –None of the above

115 Answer b)BaSO 4 ; 1 Section 4.5, Precipitation Reactions Based on the simple rules for solubility of salts in water, barium sulfate will precipitate as a solid. The balanced equation is Ba(NO 3 ) 2 (aq) + Na 2 SO 4 (aq) → BaSO 4 (s) + 2NaNO 3 (aq)

116 Question You have separate aqueous solutions of NaOH and Ca(OH) 2 with the same concentrations. You wish to neutralize an aqueous solution of HCl. Which basic solution would require more volume to neutralize the acid? –The NaOH solution. –The Ca(OH) 2 solution. –More information is needed to answer this question.

117 Answer a)The NaOH solution. Section 4.8, Acid–Base Reactions The basic solution requiring the greater volume to neutralize the acid is the one with the smaller number of hydroxide ions available to react with the hydrogen ions.

118 Question For the reaction of sodium bromide with chlorine gas to form sodium chloride and bromine, what are the appropriate half- reactions? (ox = oxidation; re = reduction) –ox:Cl 2 + 2e –  2Cl – ; re: 2Br –  Br 2 + 2e – –ox:2Br –  Br 2 + 2e – ; re: Cl 2 + 2e –  2Cl – –ox:Cl + e –  Cl – ; re: Br  Br + + e – –ox:2Cl –  Cl 2 + 2e –  ; re: Na + + e –  Na

119 Answer b) ox: 2Br –  Br 2 + 2e – ; re: Cl 2 + 2e –  2Cl – Section 4.9, Oxidation–Reduction Reactions; Section 4.10, Balancing Oxidation–Reduction Equations The conversion of bromide ion to bromine represents an oxidation, with the loss of two electrons. The conversion of chlorine to chloride ion represents a reduction, requiring two electrons.

120 Question How many of the following are oxidation– reduction reactions? i.PCl 3 + Cl 2  PCl 5 ii.Cu + 2AgNO 3  Cu(NO 3 ) 2 + 2Ag iii.CO 2 + 2LiOH  Li 2 CO 3 + H 2 O iv.FeCl 2 + 2NaOH  Fe(OH) 2 + 2NaCl a) 0 b) 1 c) 2 d) 4

121 Answer c)2 Section 4.9, Oxidation–Reduction Reactions The answers include (i), where phosphorus undergoes an oxidation from +3 to +5 and chlorine undergoes a reduction from 0 to –1, and (ii), where copper undergoes an oxidation from 0 to +2 and silver undergoes a reduction from +1 to 0.

122 Question Which of the following is not an oxidation– reduction reaction? –A precipitation reaction. –A reaction in which a metal reacts with a nonmetal. –A combustion reaction. –The reaction of a metal with an acid. –All of the above are oxidation–reduction reactions.

123 Answer a)A precipitation reaction. Section 4.9, Oxidation–Reduction Reactions In a precipitation reaction, soluble ions combine to form an insoluble solid with the ions in their same oxidation states. The other possible answers involve elements (in the zero oxidation state) reacting to ions with nonzero charges.

124 Question What are the oxidation numbers of carbon in CO 2 and CO 3 2–, respectively? –+2, +6 –+4, +6 ––4, –4 ––4, –6 –+4, +4

125 Answer e)+4, +4 Section 4.9, Oxidation–Reduction Reactions If the oxidation state of oxygen in the oxide is –2, the carbon must be +4 for the resulting CO 2 to be neutral, and the carbon must be +4 for the CO 3 2– to have a –2 charge on the ion.

126 Question Identify the type of unbalanced reaction Mg + HCl  MgCl 2 + H 2 using the following choices: –Precipitation reaction –Acid–base reaction –Oxidation–reduction reaction –Combustion reaction

127 Answer c)Oxidation–reduction reaction Section 4.9, Oxidation–Reduction Reactions This particular reaction involves an element changing into an ion and an ion changing into the element, both of which result in changes in the oxidation states of the species.

128 Question Each of the following results in a chemical reaction. Which of these is not an oxidation–reduction reaction? –Methane gas is burned in air. –Iodine crystals are added to an aqueous solution of silver nitrate. –A piece of silver metal is placed in an aqueous solution of copper(II) nitrate. –Chlorine gas is bubbled through an aqueous solution of sodium bromide. –Aqueous solutions of lead(II) nitrate and sodium iodide are mixed together.

129 Answer e) Aqueous solutions of lead(II) nitrate and sodium iodide are mixed together. Section 4.9, Oxidation–Reduction Reactions Choice (e) describes a precipitation reaction. The other choices all include elements that become part of a compound.

130 Question Which of the following compounds contains nitrogen with the highest oxidation number? –NH 3 –NO 2 –NCl 3 –N 2 –NO

131 Answer b) NO 2 Section 4.9, Oxidation–Reduction Reactions The oxidation states of nitrogen are as follows: NH 3, –3; NO 2, +4; NCl 3, +3; N 2, 0; NO, +2.

132 Chemical Impact

133 Chemical Impact Arrhenius A Man with Solutions (p.132) Science is a human endeavor, subject to frailties and governed by personalities, politics, and prejudices. One of the best illustrations of the often bumpy path of The advancement of scientific knowledge is the story of Swedish chemist Svante Arrhenius. …… Such a setbakc could have ended his scientific career, but Arrhenius was a crusader; he was determined to see his theory thriumph. He promptly embarked on a political campaign, enlisted the aid of several prominent scientists, to get his theory accepted. Ultimately, the ionic theory triumphed. Arrhenius’ fame Spread, and honors heaped on him, culminating in the Nobel Prize in chemistry in Not one to rest on his laurels., Arrhenius turned to new fields, including astronomy, He formulated a new theory that the solar system may have Come into being through the collision of stars. His exceptional Versatility led him to study the use of serums to fight disease, Energy resources and conservation, and the origin of life.

134 Chemical Impact: Tiny Laboratories (p.138) Labchip by Caliper Technologies (Palo Alto, CA), showing photolithographically etched fluid channels (in red). Channels are typically 70 µm wide and 10 µm deep. Photo Courtesy Caliper Technologies.

135 Chemical Impact Iron Zeros In On Pollution (p.156) (Chlorinated organic compound)

136 Chemical Impact : Pearly White (p.159) Ca 5 (PO 4 ) 3 (OH) (Ca 10 (PO 4 ) 6 (OH) 2 because there are two molecules in a unit cell.) 瑭瓷 牙本質 牙髓 牙齦 牙骨質 Carbamide Peroxide Teeth Whiteners: 1:1 mixture of urea and hydrogen peroxide ( H 2 O 2 ), glycerin (see next page), statnnate ( SnO 4 4- ), pyrophosphate salts (P 2 O 7 4-, preservatives) and flavoring agents.

137 Glycerol (C 3 H 5 (OH) 3 ) 甘油(甘醇,丙三醇) IUPAC namePropane-1,2,3-triol Other namesglycerin glycerine propane-1,2,3-triol 1,2,3-propanetriol 1,2,3-trihydroxypropane glyceritol glycyl alcohol

138 Chemical Impact : Aging: Does It Involve Oxidation (p.160) Wrinkles, susceptibility, subsequently, activated molecules, immune system, cell membrane, detrimental, irreplaceable, fall into this category. Vitamin E (anti-oxidant), red blood cell (RBC), superoxide dismutase (SOD, anti-oxidant), gerontology, rheumatoid arthritis, muscular dystrophy.

139 Superoxide dismutase ( 超氧化歧化酶 ) The enzyme superoxide dismutase (SOD, EC ), catalyzes theEC dismutationdismutation of superoxide into oxygen and hydrogen peroxide. As such, it is an important antioxidant defense in nearly all cells exposedsuperoxideoxygenhydrogen peroxideantioxidant to oxygen. One of the exceedingly rare exceptions is Lactobacillus plantarumLactobacillus plantarum and related lactobacilli, which use alactobacilli different mechanism. The SOD-catalysed dismutation of superoxide may be written with the following half-reactions :dismutationsuperoxide M (n+1)+ − SOD + O 2− → M n+ − SOD + O 2 M n+ − SOD + O 2− + 2H + → M (n+1)+ − SOD + H 2 O 2. where M = Cu (n=1) ; Mn (n=2) ; Fe (n=2) ; Ni (n=2).CuMnFeNi In this reaction the oxidation state of the metal cation oscillates between n and n+1oxidation state

140

141 第 4 章習題涉及的分子或反應


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