Hgcl2 2ki Hgi2 2kcl Net Ionic
up the melting point of CBr4. How does your predicted value compare with the reported value? Calcium and magnesium form the following compounds: CaCl2, MgCl2, CaO, MgO, Ca3N2, and Mg3N2. Predict the formula for a compound of (a) magnesium and sulfur, (b) barium and bromine.
The formulas of some hydrides of second-period repre-
sentative elements are as follows: BeH2, BH3, CH4, NH3, H2O, HF. A famous test in criminology laboratories for the presence of arsenic (As) involves the formation of arsine, the hydride of arsenic. Predict the formula of arsine.
Arsine burns to form a dark spot.
9. Distinguish between the following terms clearly and concisely, and provide specific examples of each: groups (families) of elements, and periods of elements.
10. Write names and symbols for (a) the alkaline earth metals, (b) the Group IVA elements, (c) the Group VIB elements.
11. Write names and symbols for (a) the alkali metals, (b) the noble gases, (c) the Group IIIA elements.
12. Define and illustrate the following terms clearly and concisely: (a) metals, (b) nonmetals, (c) halogens.
Aqueous Solutions
13. Define and distinguish among (a) strong electrolytes, (b) weak electrolytes, and (c) nonelectrolytes.
14. Three common classes of compounds are electrolytes. Name them, and give an example of each.
15. Define (a) acids, (b) bases, (c) salts, and (d) molecular compounds.
16. How can a salt be related to a particular acid and a particular base?
17. List the names and formulas of the common strong acids.
18. Write equations for the ionization of the following acids: (a) hydrochloric acid, (b) nitric acid, (c) chloric acid.
19. List names and formulas of five weak acids.
20. List names and formulas of the common strong bases.
21. Write equations for the ionization of the following acids.
Which ones ionize only slightly? (a) HF, (b) H2SO3, (c) CH3COOH, (d) HNO3.
22. The most common weak base is present in a common household chemical. Write the equation for the ionization of this weak base.
23. Summarize the electrical properties of strong electrolytes, weak electrolytes, and nonelectrolytes.
24. What is the difference between ionization and dissociation in aqueous solution?
25. List names and formulas of five insoluble bases.
26. Many household "chemicals" are acidic or basic. List a few of each kind.
27. What are reversible reactions? Give some examples.
28. Which of the following are strong electrolytes? Weak electrolytes? Nonelectrolytes? (a) NaNO3, (b) Ba(OH)2, (c) CH3OH, (d) HCN, (e) Al(NO3)3.
29. Classify the following as strong electrolytes, weak electrolytes, or nonelectrolytes: (a) HClO4, (b) HQO2, (c) CH3CH2OH, (d) CH3COOH, (e) HNO3.
30. Write the formulas of two soluble and two insoluble chlorides, sulfates, and hydroxides.
31. Describe an experiment for classifying each of these compounds as a strong electrolyte, a weak electrolyte, or a nonelectrolyte: Na2CO3, HCN, CH3OH, H2S, H2SO4, NH3. Predict and explain the expected results.
32. (a) W3 hich of these are acids? HI, NH3, H2SeO4, BF3, Fe(OH)3, H2S, C6H6, CsOH, H3PO3, HCN. (b) Which of these are bases? NaOH, H2Se, BCl3, NH3.
33. Classify each substance as either an electrolyte or a nonelectrolyte: NH4Cl, HBr, C6H6, Zn(CH3COO)2, Cu(NO3)2, CH3COOH, C12H22O11 (sugar), LiOH, KHCO3, CCl4, La2(SO4)3, I2.
*34. Classify each substance as either a strong or weak electrolyte, and then list (a) the strong acids, (b) the strong bases, (c) the weak acids, and (d) the weak bases. NaCl, MgSO4, HCl, H2C2O4, Ba(NO3)2, H3PO4, CsOH, HNO3, HI, Ba(OH)2, LiOH, C2H5COOH, NH3, KOH, Mg(CH3COO)2, HCN, HClO4.
35. Some chemical reactions reach an equilibrium, rather than going to completion. What is "equal" in such an equilibrium?
36. Vinegar is 5% acetic acid, an organic acid, by mass. Many organic acids occur in living systems. What conclusion can be drawn from this information as to the strengths of organic acids?
Oxidation Numbers
37. Assign oxidation numbers to the element specified in each group of compounds.
(a) N in NO, N2O3, N2O4, NH3, N2H4, NH2OH, hno2, hno3
(b) C in CO, CO2, CH2O, CH4O, C2H6O, (COOH)2, Na2CO3
38. Assign oxidation numbers to the element specified in each group of compounds.
H4P2O7, Mg3(PO4)2
(b) Cl in Cl2, HCl, HClO, HClO2, KClO3, Cl2O7, Ca(ClO4)2
39. Assign oxidation numbers to the element specified in each group of ions.
40. Assign oxidation numbers to the element specified in each group of ions.
Oxidation - Reduction Reactions
41. Define and illustrate the following terms: (a) oxidation, (b) reduction, (c) oxidizing agent, (d) reducing agent.
42. Why must oxidation and reduction always occur simultaneously in chemical reactions?
43. Determine which of the following are oxidation-reduction reactions. For those that are, identify the oxidizing and reducing agents.
44. Determine which of the following are oxidation-reduction reactions. For those that are, identify the oxidizing and reducing agents.
45. Write balanced formula unit equations for the following redox reactions:
(a) aluminum reacts with sulfuric acid, H2SO4, to produce aluminum sulfate, A^(SO4)3, and hydrogen
(b) nitrogen, N2, reacts with hydrogen, H2, to form ammonia, NH3
(c) zinc sulfide, ZnS, reacts with oxygen, O2, to form zinc oxide, ZnO, and sulfur dioxide, SO2
(d) carbon reacts with nitric acid, HNO3, to produce nitrogen dioxide, NO2, carbon dioxide, CO2, and water
(e) sulfuric acid reacts with hydrogen iodide, HI, to produce sulfur dioxide, SO2, iodine, I2, and water
46. Identify the oxidizing agents and reducing agents in the oxidation-reduction reactions given in Exercise 45.
47. Write total ionic and net ionic equations for the following redox reactions occurring in aqueous solution or in contact with water:
2MnCl2 + 2KCl + 5Cl2 + 8H2O (Note: MnCl2 is water-soluble.)
48. The air we inhale contains O2. We exhale CO2 and H2O. Does this suggest that our bodily processes involve oxidation? Why?
Combination Reactions
49. Write balanced equations that show the combination reactions of the following Group IA metals combining with the Group VILA nonmetals. (a) Li and C^, (b) K and F2, (c) Na and I2
50. Write balanced equations that show the combination reactions of the following Group IIA metals and Group VIIA nonmetals. (a) Be and F2, (b) Ca and Br2, (c) Ba and Cl2
51. Phosphorus and fluorine can react to form two compounds. Write balanced equations for these reactions. Which reaction requires excess phosphorus and which requires excess fluorine?
52. Two binary compounds contain arsenic and chlorine. What are their formulas? Under what conditions could each be formed?
In Exercises 53 and 54, some combination reactions are described by words. Write the balanced chemical equation for each, and assign oxidation numbers to elements other than H and O.
53. (a) Antimony reacts with a limited amount of chlorine to form antimony(III) chloride.
(b) Antimony(III) chloride reacts with excess chlorine to form antimony(V) chloride.
(c) Carbon burns in a limited amount of oxygen to form carbon monoxide.
54. (a) Sulfur trioxide reacts with aluminum oxide to form aluminum sulfate.
(b) Dichlorine heptoxide reacts with water to form perchloric acid.
(c) When cement "sets," the main reaction is the combination of calcium oxide with silicon dioxide to form calcium silicate, CaSiO3.
Decomposition Reactions
In Exercises 55 and 56, write balanced formula unit equations for the reactions described by words. Assign oxidation numbers to all elements.
55. (a) Hydrogen peroxide, H2O2, is used as an antiseptic. Blood causes it to decompose into water and oxygen.
(b) When heated, ammonium nitrate can decompose explosively to form nitrogen oxide and steam.
56. (a) A "classroom volcano" is made by heating solid ammo nium dichromate, (N^^C^Oy, which decomposes into nitrogen, chromium(III) oxide, and steam. (b) At high temperatures, sodium nitrate (a fertilizer) forms sodium nitrite and oxygen.
Displacement Reactions
57. Which of the following would displace hydrogen when a piece of the metal is dropped into dilute H2SO4 solution? Write balanced total ionic and net ionic equations for the reactions: Zn, Cu, Sn, Al.
58. Which of the following metals would displace copper from an aqueous solution of copper(II) sulfate? Write balanced total ionic and net ionic equations for the reactions: Hg, Zn, Fe, Pt.
59. Arrange the metals listed in Exercise 57 in order of increasing activity.
60. Arrange the metals listed in Exercise 58 in order of increasing activity.
61. Which of the following metals would displace hydrogen from cold water? Write balanced net ionic equations for the reactions: Zn, Na, Ca, Cr.
62. Arrange the metals listed in Exercise 61 in order of increasing activity.
63. What is the order of decreasing activity of the halogens?
64. Of the possible displacement reactions shown, which one(s) could occur?
65. (a) Name two common metals: one that does not displace hydrogen from water, and one that does not displace hydrogen from water or acid solutions. (b) Name two common metals: one that does displace hydrogen from water, and one that displaces hydrogen from acid solutions but not from water. Write net ionic equations for the reactions that occur.
66. Predict the products of each mixture. If a reaction occurs, write the net ionic equation. If no reaction occurs, write "no reaction."
67. Use the activity series to predict whether or not the following reactions will occur:
(d) Mg(s) + H2O(g) n MgO(s) + H2(g) 68. Repeat Exercise 67 for
Metathesis Reactions
Exercises 69 and 70 describe precipitation reactions in aqueous solutions. For each, write balanced (i) formula unit, (ii) total ionic, and (iii) net ionic equations. Refer to the solubility guidelines as necessary.
69. (a) Black-and-white photographic film contains some sil ver bromide, which can be formed by the reaction of sodium bromide with silver nitrate.
(b) Barium sulfate is used when x-rays of the gastrointestinal tract are made. Barium sulfate can be prepared by reacting barium chloride with dilute sulfuric acid.
(c) In water purification systems small solid particles are often "trapped" as aluminum hydroxide precipitates and falls to the bottom of the sedimentation pool. Aluminum sulfate reacts with calcium hydroxide (from lime) to form aluminum hydroxide and calcium sulfate.
70. (a) Our bones are mostly calcium phosphate. Calcium chloride reacts with potassium phosphate to form calcium phosphate and potassium chloride.
(b) Mercury compounds are very poisonous. Mercury(II) nitrate reacts with sodium sulfide to form mercury(II) sulfide, which is very insoluble, and sodium nitrate.
(c) Chromium(III) ions are very poisonous. They can be removed from solution by precipitating very insoluble chromium(III) hydroxide. Chromium(III) chloride reacts with calcium hydroxide to form chromium(III) hydroxide and calcium chloride.
In Exercises 71 through 74, write balanced (i) formula unit, (ii) total ionic, and (iii) net ionic equations for the reactions that occur between the acid and the base. Assume that all reactions occur in water or in contact with water.
71. (a) hydrochloric acid + calcium hydroxide
(b) dilute sulfuric acid + potassium hydroxide
(c) perchloric acid + aqueous ammonia
72. (a) acetic acid + potassium hydroxide
(b) sulfurous acid + sodium hydroxide
(c) hydrofluoric acid + lithium hydroxide *73. (a) potassium hydroxide + hydrosulfuric acid
(b) barium hydroxide + hydrosulfuric acid
(c) lead(II) hydroxide + hydrosulfuric acid
74. (a) sodium hydroxide + sulfuric acid
(b) calcium hydroxide + phosphoric acid
(c) copper(II) hydroxide + nitric acid
In Exercises 75 through 78, write balanced (i) formula unit, (ii) total ionic, and (iii) net ionic equations for the reaction of an acid and a base that will produce the indicated salts.
75. (a) sodium chloride, (b) sodium phosphate, (c) barium acetate
76. (a) calcium perchlorate, (b) ammonium sulfate, (c) cop-per(II) acetate
*77. (a) sodium carbonate, (b) barium carbonate, (c) nickel(II) nitrate
*78. (a) sodium sulfide, (b) aluminum phosphate, (c) lead(II) arsenate
79. (a) Propose a definition for salts, as a class of compounds, on the basis of how they are formed.
(b) Provide an example, in the form of a chemical reaction, to illustrate your definition of salts.
80. We can tell from the formula of a salt how it can be produced. Write a balanced chemical equation for the production of each of the following salts: (a) magnesium sulfate, (b) aluminum sulfite, (c) potassium carbonate,
(d) zinc chlorate, (e) lithium acetate.
81. Magnesium hydroxide is a gelatinous material that forms during the water purification process in some water treatment plants because of magnesium ions in the water.
(a) Write the chemical equation for the reaction of hydrochloric acid with magnesium hydroxide. (b) Explain what drives this reaction to completion.
Precipitation Reactions
82. A common test for the presence of chloride ions is the formation of a heavy, white precipitate when a solution of silver nitrate is added. (a) Write the balanced chemical equation for the production of silver chloride from silver nitrate solution and calcium chloride solution. (b) Explain why this reaction goes to completion.
83. Based on the solubility guidelines given in Table 4-8, how would you write the formulas for the following substances in a total ionic equation? (a) PbSO4, (b) Na(CH3COO),
84. Repeat Exercise 83 for the following: (a) (NH4)2SO4,
(b) NaBr, (c) Sr(OH)2, (d) Mg(OH)2, (e) Na2CO3. Refer to the solubility guidelines given in Table 4-8. Classify the compounds in Exercises 85 through 88 as soluble, moderately soluble, or insoluble in water.
86. (a) BaSO4, (b) Al(NO3)3, (c) CuS, (d) Na2S, (e) Ca(CH3COO)2
87. (a) Fe(NO,;)3, (b) Hg(CH3COO)2, (c) BeCl2, (d) CuSO4, (e) CaCO33 3 3 2 2 4
88. (a) KClO3, (b) NH4Cl, (c) NH3, (d) HNO2, (e) PbS
In Exercises 89 and 90, write balanced (i) formula unit, (ii) total ionic, and (iii) net ionic equations for the reactions that occur when aqueous solutions of the compounds are mixed.
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