3.4 DOUBLE DISPLACEMENT REACTIONS

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1 12. The student is to use the Internet to research the composition of various steels and to choose one alloy and list its properties and its applications. The student is then to write a short infomercial advertising the benefits of this material to potential users and to include any precautions necessary for its safe use. GO TO Chemistry 11, Teacher Centre 13. The student is to use the Internet to research the applications of aluminum and its alloys and the environmental issues surrounding aluminum production. The student is to use the findings to comment on the following statement: Risks to the environment posed by mining and refining aluminum are outweighed by the technological benefits of aluminum alloys. PRACTICE (Page 135) GO TO Chemistry 11, Teacher Centre Making Connections 14. The student is to research one of the careers listed on page 135 or a related career, and write a report that: (a) provides a general description of the nature of the work and how chemical reactions are involved; (b) describes the educational background and the length of study required to obtain employment in this field; (c) gives examples of programs offered by educational institutions leading to this career; (d) forecasts employment trends for this field; and (e) describes working conditions and salary. GO TO Chemistry 11, Teacher Centre 3.4 DOUBLE DISPLACEMENT REACTIONS PRACTICE (Page 138) 1. The following monatomic ions form compounds that have high solubility in water: Group 1 monatomic ions that form compounds with Cl,Br, and I. Group 1 and Group 2 monatomic ions that form compounds with S NH + 4 is the positive polyatomic ion that forms compounds that all have high solubility in water. 3. (a) KCl (aq) (i) Fe(OH) 3(s) (b) Ca(NO 3 (j) PbSO 4(s) (c) Na 2 (k) Ca 3 (d) AgC 2 H 3 O 2(s) (l) KMnO 4(aq) (e) NH 4 Br (aq) (m) NH 4 NO 3(aq) (f) BaS (aq) (n) CoCl 2(aq) (g) PbI 2(s) (o) CaCO 3(aq) (h) Ca(OH PRACTICE (Page 141) 4. The reaction involves two ionic compounds as reactants. 5. (a) Cu(NO 3 + MgCl 2(aq) CuCl 2(s) + Mg(NO 3 (b) 3 Ba(OH + Fe 2 (SO 4 3 BaSO 4(s) + 2 Fe(OH) 3(s) (c) Mg(OH + H 2 Mg (d) (NH 4 S (aq) + Fe (NH 4 + FeS (s) Copyright 2002 Nelson Thomson Learning Chapter 3 Chemical Reactions 59

2 6. AB + CD AD + CB As the equation above shows, the ions change partners to form products. This type of reaction commonly occurs in aqueous solutions. 7. (a) KNO 3(aq) (b) CaCl 2(aq) (c) Mg(OH (d) Al 2 (SO 4 (e) PbI 2(s) (f) Ca 3 (g) (NH 4 CO 3(aq) 8. (a KCl (aq) + Cu(NO 3 (aq) 2 KNO 3(aq) + CuCl 2(s) (b) MgCl 2(aq) + Ca(OH Mg(OH + CaCl 2(aq) (c) MgCl 2(aq) + Ca(OH CaCl 2(aq) + Mg(OH (d) 3 K AlCl 3(aq) 6 KCl (aq) + Al 2 (SO 4 (e) CuI 2(s) + PbSO 4(s) Cu + PbI 2(s) (f) 3 CaI 2(aq) + Pb 3 3 PbI 2(s) + Ca 3 (g) (NH 4 S (aq) + CaCO 3(s) CaS (aq) + (NH 4 CO 3(aq) 9. (a) (b) 10. (a) Cl 2(g) + 2 NaBr (aq) 2 NaCl (aq) + Br 2(g) (b) H NaOH (aq) 2 H 2 + Na 2 (c) 3 Ca(NO Na 3 PO 4(aq) Ca NaNO 3(aq) 11. (a) Al (s) + 3 AgNO 3(aq) 3 Ag (s) + Al(NO (b) Cl 2(g) + 2 NaBr (aq) 2 NaCl (aq) + Br 2(g) (c) Zn (s) + H 2 + Zn (d AgNO 3(aq) + MgCl 2(aq) 2 AgCl (s) + Mg(NO 3 (e) Na 2 C 2 O 4(aq) + CaCl 2(aq) CaC 2 O 4(aq) + 2 NaCl (aq) (f Na (s) + 2 NaOH (aq) (g) 3 KOH (aq) + FeCl 3(aq) 3 KCl (aq) + Fe(OH) 3(s) 12. (a) Ca 3 calcium phosphate (b) 3 H 2 + Ca 3 2 H 3 PO 4(aq) + 3 CaSO 4(s) (c) The simple procedure of filtering could be employed to isolate aqueous phosphoric acid from the solid calcium phosphate. (d) If sodium phosphate is used in place of calcium phosphate as a reactant, the products of the reaction would be aqueous phosphoric acid and aqueous sodium sulfate. Sodium sulfate is highly soluble at SATP, and would pass through a simple filter. Thus the simple procedure of filtering would not be sufficient to isolate the phosphoric acid. The fertilizer manufacturer would prefer to avoid the additional costs that would be associated with a more involved process of isolating the phosphoric acid. 60 Unit 1 Matter and Chemical Bonding Copyright 2002 Nelson Thomson Learning

3 SECTIONS QUESTIONS (Page 143) 1. (a)-(e) Cl - Br - NO - 3 C 2 H 3 O 2 - PO SO OH - SO 3 2- K + KCl KBr KNO 3 KC 2 H 3 O 2 K 3 PO 4 K 2 SO 4 KOH K 2 SO 3 potassium potassium potassium potassium potassium potassium potassium potassium would not would not sdr with zinc sdr with zinc sdr with zinc sdr with zinc sdr with zinc sdr with zinc occur occur would not would not would not would not would not would not occur occur occur occur occur occur Ca 2+ CaCl 2 CaBr 2 Ca(NO 3 Ca(C 2 H 3 O 2 Ca 3 CaSO 4(s) Ca(OH CaSO 3(s) calcium calcium calcium calcium calcium calcium calcium calcium would not would not sdr with zinc sdr with zinc sdr with zinc sdr with zinc sdr with zinc sdr with zinc occur occur would not would not would not would not would not would not occur occur occur occur occur occur Al 3+ AlCl 3 AlBr 3 Al(NO 3 ) 3 Al(C 2 H 3 O 2 ) 3 AlPO 4(s) Al 2 (SO 4 ) 3 Al(OH) 3(s) Al 2 (SO 3 ) 3(s) aluminum aluminum aluminum aluminum aluminum aluminum aluminum aluminum would not would not sdr with zinc sdr with zinc sdr with zinc sdr with zinc sdr with zinc sdr with zinc occur occur would not would not would not would not would not would not occur occur occur occur occur occur Cu + CuCl CuBr CuNO 3 CuC 2 H 3 O 2 Cu 3 PO 4(s) Cu 2 SO 4 CuOH (s) Cu 2 SO 3(s) copper(i) copper(i) copper(i) copper(i) copper(i) copper(i) copper(i) copper(i) Pb 2+ PbCl 2(s) PbBr 2(s) Pb(NO 3 Pb(C 2 H 3 O 2 Pb 3 PbSO 4(s) Pb(OH PbSO 3(s) lead(ii) lead(ii) lead(ii) lead(ii) lead(ii) lead(ii) lead(ii) lead(ii) Copyright 2002 Nelson Thomson Learning Chapter 3 Chemical Reactions 61

4 Fe 3+ FeCl 3 FeBr 3 Fe(NO 3 ) 3 Fe(C 2 H 3 O 2 ) 3 FePO 4(s) Fe 2 (SO 4 ) 3 Fe(OH) 3(s) Fe 2 (SO 3 ) 3(s) iron(iii) iron(iii) iron(iii) iron(iii) iron(iii) iron(iii) iron(iii) iron(iii) Mg 2+ MgCl 2 MgBr 2 Mg(NO 3 Mg(C 2 H 3 O 2 Mg 3 MgSO 4 Mg(OH MgSO 3(s) magnesium magnesium magnesium magnesium magnesium magnesium magnesium magnesium NH + 4 NH 4 Cl NH 4 Br NH 4 NO 3 NH 4 C 2 H 3 O 2 (NH 4 ) 3 PO 4 (NH 4 SO 4 NH 4 OH (NH 4 SO 3 ammonium ammonium ammonium ammonium ammonium ammonium ammonium ammonium tertiary ionic, tertiary ionic, tertiary quaternary quaternary quaternary tertiary quaternary NOTE: All substances aqueous (aq), unless noted otherwise. sdr stands for reaction. Word and chemical equation examples: zinc + potassium chloride NR Zn (s) + KCl(aq) NR zinc + iron(iii) acetate iron + zinc acetate 3 Zn (s) + 2 Fe(C 2 H 3 O 2 2 Fe (s) + 3 Zn(C 2 H 3 O 2 62 Unit 1 Matter and Chemical Bonding Copyright 2002 Nelson Thomson Learning

5 2. 1. octane + oxygen carbon dioxide + water combustion 2 C 8 H 18(g) + 25 O 2(g) 16 CO 2(g) + 18 H 2 O (g) Rain becomes slightly acidic due to the presence of carbon dioxide, which dissolves in atmospheric moisture and reacts to form very dilute carbonic acid, H 2 CO 3(aq). Carbon dioxide gas also contributes to the greenhouse effect, which may lead to global warming and dramatic climate changes. 2. sulfur + oxygen sulfur dioxide synthesis (combustion) S (s) SO 2(g) Sulfur dioxide joins the naturally produced oxides in the atmosphere, and reacts with water vapour to form acids, and is responsible for the increased acidity of precipitation known as acid rain. 3. nitrogen + oxygen nitrogen monoxide synthesis (combustion) N 2(s) 2 NO (g) Nitrogen monoxide joins the naturally produced oxides in the atmosphere, and reacts with water vapour to form acids, and is responsible for the increased acidity of precipitation known as acid rain. 4. nitrogen monoxide + oxygen nitrogen dioxide synthesis Pt 2 NO (s) 2 NO (g) Nitrogen dioxide joins the naturally produced oxides in the atmosphere, and reacts with water vapour to form acids, and is responsible for the increased acidity of precipitation known as acid rain. 5. sulfur trioxide + water sulfuric acid synthesis SO 3(s) + H 2 H 2 Sulfur trioxide reacts with water vapour to form sulfuric acid, and is responsible for the increased acidity of precipitation known as acid rain. 6. nitrogen monoxide nitrogen + oxygen decomposition Pt/Pd 2 NO (g) N 2(g) The platinum/palladium catalytic converter built into today s automobiles catalyzes the decomposition of nitrogen monoxide which is a combustion engine exhaust pollutant into harmless nitrogen and oxygen. Applying Inquiry Skills 3. Analysis (a) Y would be highest in the activity series, followed by Z, and then X, as indicated below: Y Z X (b) Y and Z would be located higher in the activity series than hydrogen. X would be located lower in the activity series than hydrogen, unless in fact it is actually hydrogen. Using empirical evidence gathered in many experiments, scientists have been able to list the elements in order of their reactivity. The empirical evidence has shown that the more reactive element will replace the less reactive element. Since Y and Z showed evidence of reaction in water and acid - bubbles were observed - it is evident that Y and Z have reacted with the water and the acid to displace hydrogen and produce hydrogen gas. And since Y and Z displaced hydrogen, they cannot be hydrogen. The only possible choice for hydrogen would be X. Synthesis (c) X would appear higher in order than Y, as you descend the group. For metals, the lower the electronegativity value, the more reactive the metal should be. As the evidence showed Y to be more reactive than X, it would be expected to have a lower electronegativity value than X. And since electronegativity values decrease as you move down a group, it makes sense that X would appear higher in order than Y, as you descend the group. Y would appear to be further to the left in order than Z, as you move from left to right within the same period. For metals, the lower the electronegativity value, the more reactive the metal should be. As the evidence showed Y to be more reactive than Z, it would be expected to have a lower electronegativity value than Z. And since electronegativity values increase as you move from left to right within the same period, it makes sense that Y would appear further to the left in order than Z, as you move from left to right within the same period. Copyright 2002 Nelson Thomson Learning Chapter 3 Chemical Reactions 63

6 (d) Assign the following element identities: X = Li Y = Na Z = Mg 2 Li (s) + 2 LiOH (aq) 2 Li (s) + 2 HCl (aq) + 2 LiCl (aq) 2 Na (s) + 2 NaOH (aq) 2 Na (s) + 2 HCl (aq) + 2 NaCl (aq) Mg (s) + Mg(OH Mg (s) + 2 HCl (aq) + MgCl 2(aq) (e) All reactions are reactions. With respect to the reaction with water: Use a lighted splint to ignite the gas produced. A pop sound when ignited indicates hydrogen gas. The aqueous solution could be tested with ph paper to determine if it is basic. These tests would indicate that the reaction was a type, with the metal displacing hydrogen in the water (H 2 ) to produce hydrogen gas and a metal hydroxide. With respect to the reaction with acid: Use a lighted splint to ignite the gas produced. A pop sound when ignited indicates hydrogen gas. The aqueous solution could be evaporated and the remaining compound analyzed to determine if it is a metal chloride. These tests would indicate that the reaction was a type, with the metal displacing hydrogen in the acid (HCl (aq) ) to produce hydrogen gas and a metal chloride. Making Connections Pt 4. (ak (s) + BeCl 2(s) Be (s) + 2 KCl (l) (b) Beryllium chloride should be stored dry within air and water vapour tight sealed containers. The substance should only be handled in environmentally enclosed and controlled areas, and all required protective equipment such as gas masks, protective clothing, and protective gloves should be worn. 5. (a) C (s) + SiO 2(l) Si (l) + CO 2(g) Si (s) + 2 Cl 2(g) SiCl 4(l) synthesis 2 Mg (s) + SiCl 4(l) Si (s) + 2 MgCl 2(aq) (b) Emissions of carbon dioxide gas (a product of the first reaction) cause rain to become slightly acidic. Carbon dioxide gas also contributes to the greenhouse effect, which may lead to global warming and dramatic climate changes. CHAPTER 3 REVIEW (Page 146) 1. The kinetic molecular theory states that all matter is made up of particles in continuous random motion. A gas has widely separated molecules in constant, chaotic motion. The average kinetic energy of the molecules is much larger than the energy associated with the attractive forces between them. With liquids, the attractive forces between molecules have energies comparable to the kinetic energies of the molecules. The attractive forces are able to hold the molecules close to each other. However, the attractive forces are not strong enough to hold the molecules rigidly in place. In fact, molecules within a liquid are able to move in a more or less chaotic fashion, allowing liquids to be poured, and to flow to take the shape of their container. With solids, the intermolecular attractions are sufficiently strong enough to hold the molecules rigidly in place. The average kinetic energy of the molecules is much smaller than the energy associated with the attractive forces between them. The particles of a solid are not free to move. However, the molecules within a solid may undergo vibrational motion. 64 Unit 1 Matter and Chemical Bonding Copyright 2002 Nelson Thomson Learning