CHAPTER Chemical Reactions 7 Section 7.1 Evidence for Chemical Reactions 2. (a) The water vapor is evidence for a chemical reaction. (b) The purple gas is evidence for a physical change. 4. (a) The gas bubbles are evidence for a chemical reaction. (b) The insoluble solid is evidence for a chemical reaction. 6. (a) The violet flame is evidence for a chemical reaction. (b) The gas bubbles are evidence for a chemical reaction. Section 7.2 Writing Chemical Equations 8. Fe(s) + Cl 2 (g) FeCl 2 (s) 10. Cd(HCO 3 ) 2 (s) CdCO 3 (s) + CO 2 (g) + H 2 O(g) 12. Mn(s) + Ni(NO 3 ) 2 (aq) Mn(NO 3 ) 2 (aq) + Ni(s) 14. K 2 CrO 4 (aq) + CaSO 4 (aq) CaCrO 4 (s) + K 2 SO 4 (aq) 16. HC 2 H 3 O 2 (aq) + NaOH(aq) NaC 2 H 3 O 2 (aq) + HOH(l) Section 7.3 Balancing Chemical Equations 18. (a) 4 Co(s) + 3 O 2 (g) 2 Co 2 O 3 (s) (b) 2 LiClO 3 (s) 2 LiCl(s) + 3 O 2 (g) (c) Cu(s) + 2 AgC 2 H 3 O 2 (aq) Cu(C 2 H 3 O 2 ) 2 (aq) + 2 Ag(s) (d) Pb(NO 3 ) 2 (aq) + 2 LiCl(aq) PbCl 2 (s) + 2 LiNO 3 (aq) (e) 3 H 2 SO 4 (aq) + 2 Al(OH) 3 (aq) Al 2 (SO 4 ) 3 (aq) + 6 HOH(l) 2014 Pearson Education, Inc. Chemical Reactions 39
20. (a) 2 HClO 4 (aq) + Ba(OH) 2 (aq) Ba(ClO 4 ) 2 (aq) + 2 HOH(l) (b) Co(NO 3 ) 2 (aq) + H 2 S(g) CoS(s) + 2 HNO 3 (aq) (c) 2 Fe(s) + 3 Cd(NO 3 ) 2 (aq) 2 Fe(NO 3 ) 3 (aq) + 3 Cd(s) (d) Fe 2 (CO 3 ) 3 (s) Fe 2 O 3 (s) + 3 CO 2 (g) (e) 3 Sn(s) + 2 P(s) Sn 3 P 2 (g) Section 7.4 Classifying Chemical Reactions 22. Refer to the chemical reactions in Exercise 18. (a) combination reaction (b) decomposition reaction (c) single-replacement reaction (d) double-replacement reaction (e) neutralization reaction 24. Refer to the chemical reactions in Exercise 20. (a) neutralization reaction (b) double-replacement reaction (c) single-replacement reaction (d) decomposition reaction (e) combination reaction Section 7.5 Combination Reactions General Form: A + Z AZ 26. metal + oxygen gas metal oxide (a) Sn(s) + O 2 (g) SnO 2 (s) (b) 2 Pb(s) + O 2 (g) 2 PbO(s) 28. nonmetal + oxygen gas nonmetal oxide (a) 2 N 2 (g) + 5 O 2 (g) 2 N 2 O 5 (g) (b) 2 Cl 2 (g) + 3 O 2 (g) 2 Cl 2 O 3 (g) 30. metal + nonmetal ionic compound (a) 2 Fe(s) + 3 F 2 (g) 2 FeF 3 (s) (b) 3 Pb(s) + 4 P(s) Pb 3 P 4 (s) 32. (a) S(s) + O 2 (g) SO 2 (g) (b) 2 S(s) + 3 O 2 (g) Pt 34. (a) 2 Sr + O 2 2 SrO (b) 4 Al + 3 O 2 2 Al 2 O 3 36. (a) 3 Zn + 2 P Zn 3 P 2 (b) 2 Al + 3 S Al 2 S 3 2 SO 3 (g) 40 Chapter 7 2014 Pearson Education, Inc.
Section 7.6 Decomposition Reactions General Form: AZ A + Z 38. metal hydrogen carbonate metal carbonate + water + carbon dioxide (a) 2 AgHCO 3 (s) Ag 2 CO 3 (s) + H 2 O(g) + CO 2 (g) (b) Ni(HCO 3 ) 2 (s) NiCO 3 (s) + H 2 O(g) + CO 2 (g) 40. metal carbonate metal oxide + carbon dioxide (a) Cr 2 (CO 3 ) 3 (s) Cr 2 O 3 (s) + 3 CO 2 (g) (b) Pb(CO 3 ) 2 (s) PbO 2 (s) + 2 CO 2 (g) 42. metal carbonate metal oxide + carbon dioxide (a) Li 2 CO 3 (s) Li 2 O(s) + CO 2 (g) (b) CdCO 3 (s) CdO(s) + CO 2 (g) 44. oxygen containing compounds oxygen gas (a) Sn(ClO 3 ) 2 (s) SnCl 2 (s) + 3 O 2 (g) (b) 2 PbO 2 (s) 2 PbO(s) + O 2 (g) 46. oxygen containing compounds oxygen gas (a) 2 AlPO 4 (s) 2 AlPO 3 (s) + O 2 (g) (b) 2 SnSO 4 (s) 2 SnSO 3 (s) + O 2 (g) Section 7.7 The Activity Series Concept 48. Element Solution Observation (a) Hg Cd(NO 3 ) 2 (aq) no reaction: Cd > Hg (b) Pb Cd(NO 3 ) 2 (aq) no reaction: Cd > Pb (c) Ni Cd(NO 3 ) 2 (aq) no reaction: Cd > Ni (d) Cr Cd(NO 3 ) 2 (aq) reaction: Cr > Cd 50. Element Solution Observation (a) Hg HCl(aq) no reaction: (H) > Hg (b) Pb HCl(aq) reaction: Pb > (H) (c) Ni HCl(aq) reaction: Ni > (H) (d) Cr HCl(aq) reaction: Cr > (H) 52. Element Water Observation (a) Ba H 2 O(l) reaction: Ba is an active metal (b) Mn H 2 O(l) no reaction: Mn is not an active metal (c) Sn H 2 O(l) no reaction: Sn is not an active metal (d) K H 2 O(l) reaction: K is an active metal 2014 Pearson Education, Inc. Chemical Reactions 41
Section 7.8 Single-Replacement Reactions General Form: A + BZ AZ + B or: A + BZ NR 54. metal 1 + aqueous solution 1 metal 2 + aqueous solution 2 (a) Ag(s) + Cd(NO 3 ) 2 (aq) NR (b) Cd(s) + 2 AgNO 3 (aq) 2 Ag(s) + Cd(NO 3 ) 2 (aq) 56. metal 1 + aqueous solution 1 metal 2 + aqueous solution 2 (a) Fe(s) + HgSO 4 (aq) Hg(l) + FeSO 4 (aq) (b) Hg(l) + FeSO 4 (aq) NR 58. metal + aqueous acid aqueous solution + hydrogen gas (a) Zn(s) + H 2 CO 3 (aq) ZnCO 3 (aq) + H 2 (g) (b) Cd(s) + 2 HC 2 H 3 O 2 (aq) Cd(C 2 H 3 O 2 ) 2 (s) + H 2 (g) 60. metal + water metal hydroxide + hydrogen gas (a) 2 Cs(s) + 2 H 2 O(l) 2 CsOH(aq) + H 2 (g) (b) Ra(s) + 2 H 2 O(l) Ra(OH) 2 (aq) + H 2 (g) 62. metal 1 + aqueous solution 1 metal 2 + aqueous solution 2 (a) Mg(s) + NiSO 4 (aq) MgSO 4 (aq) + Ni(s) (b) 2 Al(s) + 3 SnSO 4 (aq) Al 2 (SO 4 ) 3 (aq) + 3 Sn(s) 64. metal + aqueous acid aqueous solution + hydrogen gas (a) Mg(s) + H 2 SO 4 (aq) MgSO 4 (aq) + H 2 (g) (b) 2 Al(s) + 3 H 2 SO 4 (aq) Al 2 (SO 4 ) 3 (aq) + 3 H 2 (g) 66. metal + water metal hydroxide + hydrogen gas (a) Mg(s) + H 2 O(l) NR (b) Ca(s) + 2 H 2 O(l) Ca(OH) 2 (aq) + H 2 (g) Section 7.9 Solubility Rules 68. (a) (NH 4 ) 2 S soluble (b) ZnCO 3 insoluble (c) SnCrO 4 insoluble (d) Pb(C 2 H 3 O 2 ) 2 soluble 70. (a) SrCO 3 insoluble (b) Ca(OH) 2 soluble (c) NiS insoluble (d) HgBr 2 soluble 42 Chapter 7 2014 Pearson Education, Inc.
Section 7.10 Double-Replacement Reactions General Form: AX + BZ AZ + BX or: AX + BZ NR 72. aqueous solution 1 + aqueous solution 2 precipitate + aqueous solution 3 (a) CrI 3 (aq) + 3 NaOH(aq) Cr(OH) 3 (s) + 3 NaI(aq) (b) NiSO 4 (aq) + Hg 2 (NO 3 ) 2 (aq) Hg 2 SO 4 (s) + Ni(NO 3 ) 2 (aq) 74. aqueous solution 1 + aqueous solution 2 precipitate + aqueous solution 3 (a) MgSO 4 (aq) + BaCl 2 (aq) BaSO 4 (s) + MgCl 2 (aq) (b) 2 AlBr 3 (aq) + 3 Na 2 CO 3 (aq) Al 2 (CO 3 ) 3 (s) + 6 NaBr(aq) Section 7.11 Neutralization Reactions General Form: HX + BOH BX + HOH 76. aqueous acid + aqueous base aqueous salt + water (a) H 3 PO 4 (aq) + 3 KOH(aq) K 3 PO 4 (aq) + 3 HOH(l) (b) 2 HC 2 H 3 O 2 (aq) + Sr(OH) 2 (aq) Sr(C 2 H 3 O 2 ) 2 (aq) + 2 HOH(l) 78. aqueous acid + aqueous base aqueous salt + water (a) 2 HNO 3 (aq) + Sr(OH) 2 (aq) Sr(NO 3 ) 2 (aq) + 2 HOH(l) (b) H 2 SO 3 (aq) + 2 NaOH(aq) Na 2 SO 3 (s) + 2 HOH(l) General Exercises 80. No. Conservation of mass requires the same number of atoms of each element for reactants and products. In the following balanced equation, the coefficients are 5 and 1, respectively: 2 Fe(s) + 3 O 2 (g) Fe 2 O 3 (s). 82. (a) 3 FeO(l) + 2 Al(l) Al 2 O 3 (l) + 3 Fe(l) (b) 3 MnO 2 (l) + 4 Al(l) 2 Al 2 O 3 (l) + 3 Mn(l) 84. (a) PCl 5 (s) + 4 H 2 O(l) H 3 PO 4 (aq) + 5 HCl(aq) (b) TiCl 4 (s) + 2 H 2 O(g) TiO 2 (s) + 4 HCl(g) 86. (a) 2 CH 4 O(l) + 3 O 2 (g) 2 CO 2 (g) + 4 H 2 O(g) (b) 2 C 3 H 8 O(l) + 9 O 2 (g) 6 CO 2 (g) + 8 H 2 O(g) 2014 Pearson Education, Inc. Chemical Reactions 43
Challenge Exercises 88. Industrial Preparation of Chlorine: 4 HCl(g) + O 2 (g) 2 Cl 2 (g) + 2 H 2 O(g) Online Exercises 90. Contact Process for Manufacturing Sulfuric Acid: (1) S(s) + O 2 (g) SO 2 (g) Pt (2) 2 SO 2 (g) + O 2 (g) 2 SO 3 (g) (3) SO 3 (g) + H 2 O(l) H 2 SO 4 (aq) 44 Chapter 7 2014 Pearson Education, Inc.