Chemistry 12 Solutions Manual Part A Unit 1 Organic Chemistry Answers to Unit 1 Preparation Questions (Student textbook pages 4-5) 1. e 2. e 3. In addition to the equipment listed, include location of main gas shut-off valve, fume hood (if equipped), exits to hallway, location of lab benches or other work area. 4. Student answer will include • Fire extinguisher type (A, B, C, D, ABC). • Face the fire with a clear path to an exit available behind you. • A fire extinguisher lasts for about 30 s. If the fire cannot be extinguished in this time, leave the area and activate a fire alarm. • Pull the pin from the top of the extinguisher to release the tamper seal, activating the extinguisher. • Aim the nozzle or nose of the extinguisher toward the base or bottom of the fire. You want to attack the fire at the source. Remember, this is one time you want to aim low. • Squeeze the handle down toward the extinguisher. Depressing the handle releases the extinguishing element. • Sweep across the fire in a side to side motion until the fire appears to be out. • Watch the fire closely. If there seem to be any signs of the fire reigniting, repeat the last 4 steps. 5. Emphasize possibility of spills and splashing of chemicals onto hands and clothing. Also the possibility of losing track of the identity of the contents in a beaker or flask and the mixing, by mistake, of clear, colourless solutions (such as vinegar and solution of baking soda) that will produce a gas, causing splattering. Also, some common kitchen chemicals such as oven cleaners and drain cleaners are dangerous and safety gear should be used at home. 6. Mixing of paper waste can cover broken glass which presents a danger to the person disposing of this waste, risking possible cuts and exposure to infection. 7. d 8. a. Wear protective eyewear, apron, thermal gloves; know location of fire extinguisher, fire blanket, tie back long hair, do not wear loose clothing. b. Read label on the cylinder; be aware of reading on pressure gauge, hold cylinder with both hands, pointing the outlet away from your body; open valve slowly. c. Wear protective eyewear, apron, and protective gloves. d. Wear protective eyewear, apron, and protective gloves. Know the location of eyewash station, tie back long hair, do not wear loose clothing. e. Wear protective eyewear, apron, protective gloves, tie back long hair, do not wear loose clothing. 9. a. poisonous material causing immediate and serious toxic effects b. flammable and combustible c. corrosive d. compressed gas 10. a. The attraction between two atoms that results from the sharing of electrons. b. A compound in which the atoms are held together by covalent bonds. c. The electrostatic attraction between a negatively charged ion and a positively charged ion. d. The temperature at which a pure substance changes from the solid state to the liquid state. e. The temperature at which a pure substance changes from the liquid state to the gaseous state. 11. b 12. d 13. Melting involves separating molecules from their fixed position in the solid state. Polar molecules have a definite shape with areas of fixed negative and positive charge. The electrical attraction between these oppositely charged areas on different molecules (dipole-dipole) must be overcome for melting to occur. This takes more energy than that which is needed to overcome relatively weak attractions (dispersion forces) between non-polar molecules. 14. Cl2, non-polar covalent molecule < CH3OH, polar covalent molecule < K2O, ionic compound Unit 1 Part A • MHR 1 adopting the symmetrical, tetrahedral arrangement of its bonds. 15. Heat and light are given off 16. No. Hazardous (causing injury to health) products come from combustion of a hydrocarbon is CO(g), which does not form with excess O2. CH3 5. H2C 17. hydrocarbon and oxygen 18. a. Incomplete combustion occurs when there is insufficient oxygen to react with all of the reactants (such as hydrocarbons). Products other than carbon dioxide and water are carbon (soot) and carbon monoxide. Less heat is given off, and it is less efficient than complete combustion. b. Carbon monoxide is clear, colourless, and odourless. It can accumulate and overcome a person, causing death. (Student textbook page 11) 1. Up to and including the 1800s, the term organic was used to describe matter that came from living organisms that contained a “vital energy,” and inorganic was used to describe matter that came from non-living material. The laboratory synthesis of compounds once thought to be produced only by living organisms led to the modern definition of an organic compound as one in which carbon atoms are bonded to each other, to hydrogen atoms, and sometimes to a few specific elements, usually oxygen, nitrogen, sulfur, or phosphorus. 2. The key to carbon’s ability to bond with several atoms is found in its atomic structure. A carbon atom has four valence electrons, and a half-filled outer shell of electrons. It has an intermediate electronegativity and is much more likely to share electrons than to gain or lose enough electrons to form ions. Its four valence electrons can be shared with up to four other atoms. This leads to the potential for the formation of a wide variety of molecules. 3. Any molecule that contains C–C or C–H are considered organic, and molecules or ions such as CO2 and CO32– that contain no C–C or C–H bonds are considered inorganic. 4. Atomic systems arrange themselves to minimize their potential energy. For methane, this occurs if the four bonds are as far apart as possible (because the electron pairs repel each other), which the molecule achieves by 2 MHR • Chemistry 12 Solutions Manual 978-0-07-106042-4 CH2 CH3 CH2 CH2 CH2 CH2 CH3 6. There are nine constitutional isomers of heptane. H H H H H H H H C C C C C C C H H H H H H H H H H H H Chapter 1 Structure and Physical Properties of Organic Compounds Answers to Learning Check Questions CH3 H H C H H H H H C C C C C C H H H H H H H C H H H H H C C C C C C H H H H H H C H H H H C C C C C H H H H H H C H H H C H H H C C H H H H C C H H H H C C C C H H C H H H H H H H C C H H C C C H H H C H H H H H H H H H H H H H H H H H H H H H C H H H C H H H H C C C C C H H H H H H H H H H C C C C H H H C H H H H H H C H H H H H C H H C C C C H H H H H C H H (Student textbook page 19) 7. Examples include methane (CH4) found in natural gas to heat homes, propane (C3H8) used in barbeques and as a heating fuel,c12_techart_c1-lc_ans6 butane (C4H8) found in lighters and portable burners, octane (C8H18) found in gasoline, Art is) too wide to fit in column width. waxes (C20H 42 found in candles, and tars (C40H82) used in paving. 8. In a saturated hydrocarbon, each carbon atom is bonded to as many other atoms as possible. Unsaturated hydrocarbons have at least one multiple bond and are therefore not bonded to as many other atoms as possible, or they are not completely saturated with hydrogen atoms. 9. A homologous series is a set of molecules in which each member differs from the next by an additional specific structural unit. The alkane series can be represented by a general formula, CnH2n+2. Ethane, C2H6, differs from the next member of the series, propane, C3H8, by –CH2. 10. 3 carbon atoms: C3H8; 7 carbon atoms: C7H16; 9 carbon atoms: C9H20; 12 carbon atoms: C12H26 11. All reasonable answers should show that an atom or group of atoms on an alkane has been substituted in place of a hydrogen atom on the parent chain of carbons. 15. a. Alkanes that are liquids at room temperature have between 5 and 16 carbon atoms inclusive. b. Alkanes that are gases at room temperature have between 1 and 4 carbon atoms inclusive. 16. CnH2n 17. They are similar in that they have the same number and sequence of carbon atoms as the corresponding alkane. They are different in that there are fewer hydrogen atoms in an alkene, there is a double bond in an alkene, and the shape is different. 18. For example H H H H H C C C H H H H H H C C C H H C H H H3C CH CH H2C CH CH2 CH3 CH3 CH3 H H3C C CH2 (Student textbook page 32) 19. H3C CH CH CH2 CH2 CH3 H2C CH H3C CH2 CH CH CH2 CH3 H3C C CH2 CH2 CH2 CH3 H Substituent group EmpericalHformula 12. The root is pent-, the prefix is 2-methyl, and the suffix is C4H -ane. 10 Condensed structural formula (Student textbook page 24) Emperical formula 13. Empirical formula H3C CH2 CH2 Emperical formula C4HC4H 10 H3C C CH2 CH CH3 H3C CH3 H3C CH CH2 CH CH2 H3C LineLine structural H H formula Hformula H structural Expanded Structural formula Expanded Structural formula CH3CH2CH2CH3 14. They are insoluble in water but soluble in non-polar CH3CH2CH2CH3 solvents. CH C CH2 10 Structural H Hformula H Hformula Expanded Structural H C H C H C H H H C CH3CH2CH2CH3 H H C H C H C H C H CH2 CH3 CH CH CH3 H3C H3C CH3 Expanded molecular formula C4H 10 Structural formula structural formula CHCondensed 3CH2CH2CH3 H Hstructural H H formula Condensed Condensed structural H3C CH CHformula CH3 2 2 H C C C C H H3C CH2 CH2 CH3 H H H H Structural formula Structural formula CH2 CH2 HC CH3 CH3 H3C H3C C C CH3 CH3 CH3 H3C C CH CH2 CH3 20. alkenes < alkanes < alkynes 21. The linear structure of alkynes and the nature of the triple bond allow them to attract one another more strongly than corresponding alkanes and alkenes. 22. Testosterone and estrogen are two examples of steroid hormones containing cyclic hydrocarbons. 23. Straight-chain alkanes have the general formula CnH2n+2. Cyclic alkanes have the general formula CnH2n. Alkenes have the general formula CnH2n. Alkynes have the general formula CnH2n-2. 24. At least three carbon atoms are necessary and the molecular formula is C3H6. Line structural formula Line structural formula Unit 1 Part A • MHR 3 (Student textbook page 36) 25. Cyclic hydrocarbons have higher boiling points and melting points than straight-chain hydrocarbons. There is a greater difference in terms of melting point. 26. Aromatic hydrocarbons contain a benzene ring; aliphatic hydrocarbons do not contain a benzene ring. 27. Benzene is more stable than cyclohexene (therefore, less reactive), and it has fewer hydrogen atoms. 28. All the bonds in benzene are identical and have an intermediate length compared with single and double bonds. Answers to Section 1.1 Review Questions (Student textbook page 14) 1. An organic compound is one in which carbon atoms are bonded to one another, to hydrogen and a few other non-metal elements (O, N, S P, halogens) 2. The carbon atom is bound only to oxygen atoms. There are no C–C or C–H bonds. 3. If the bond angle around carbon atoms was 90o, there would be fewer possible compounds because of greater repulsion between pairs of electrons. Also biological compounds would be restricted sheet or cubic shapes. 29. Electrons in the “double bonds” of a benzene ring are in fact shared by all six carbon atoms. They are not “localized” to a bond between two carbon atoms. H 4 MHR • Chemistry 12 Solutions Manual 978-0-07-106042-4 C H H H H benzene ring Figure 1.10 (Student textbook page 13): Triple bonds are linear and rigid and each carbon atom has only one atom attached. Figure 1.13 (Student textbook page 15): They all contain only carbon and hydrogen atoms. All contain only single bonds. Except for methane, the carbon atoms are bonded to other carbon atoms. Each compound has one more CH2 unit than the one before. Figure 1.15 (Student textbook page 22): The compound on the left is unsaturated because the carbon atoms are not bonded to the maximum number of atoms possible, owing to the double bond. The compound on the right is saturated because the carbon atoms are bonded to the maximum number of atoms; all of the bonds are single bonds. Figure 1.16 (Student textbook page 22): These two alkenes are isomers. The double bond can join an end carbon atom to another carbon atom, or the double bond can join the two middle carbon atoms. Figure 1.25 (Student textbook page 46): Possible response: The CFCs act as catalysts and thus are not used up in the reactions. The CFCs take a long time to naturally degrade in the atmosphere. Also, older products, such as old refrigerators, may still emit CFCs. Figure 1.36 (Student textbook page 70): The citric acid protonates the amines in the fish. That is, the acid adds a hydrogen ion to the amine, making it a soluble salt which is not volatile. Figure 1.43 (Student textbook page 80): It is all three. Glucosamine contains hydroxyl side groups, an amino side group, and a formyl side group. H C 30. Answers to Caption Questions H H Lewis Structure 4. a. H H C C H HH C C H H H H H C C H H C C H H H H H C H H H C C H C H H H H H H C H C C C H H H H b. C2H2Cl2 Cl H Cl C C Cl H C C Cl H H H Cl H C C 5. a. Rotation occurs around a single bond and a trans “isomer” could easily rotate into a cis “isomer” for the same molecule F H H C C H Cl H H H Cl C C F H H b. Each carbon atom in a triple bond is attached to only one other atom 180o to each other. Cl C C F 6. In the list of words, “trans” means across the nation, continent, or Atlantic respectively. The attached identical atoms or groups in the trans form are across the double bond from one another. Cl 7. The wrist, the thumb side, the fingers and flat edge on the baby finger side. 8. Venn diagram should show: Diastereomers only: • carbon atoms joined by double bond • non-mirror images, no free rotation about the double bond • cis and trans forms have different physical properties Diastereomers and enantiomers: • carbon atoms Enantiomers only: • mirror images of one another • single bonds • four different atoms bonded to carbon • same physical properties 9. The physical properties would be similar as their basic structure is the same except for the rotation of plane polarized light. Their chemical properties would also be similar. However, in living systems, the enzymes that catalyze chemical reactions recognize and bind to only one of the two enantiomers. 10. Looking at the two carbon atoms in the double bond, the one on the left is bonded to two identical CH3 groups. The groups must differ in order to form cis or trans isomers. 11. a. The ring structure of the pentane causes the carbon atoms to form a rigid plane. Notice that, in the cis isomer, the two fluorine atoms are above the plane of the cyclic carbon atoms and in the trans isomer, the two fluorine atoms are on opposite sides of the plane. cis- 1, 2 difluoropentane H H H H C trans- 1, 2 difluoropentane H C F H F C C C H H H F C C H H H C C C F H H H H b. In the linear structures, a double bond prevents rotation around the bond, thus preventing the atoms attached to the carbons atoms of the bond. In the ring structure, the ring itself prevents rotation around the single bonds, preventing an attached atom from moving from one side of the ring to the other. 12. The boiling point depends upon the intermolecular attractions between molecules. This is affected by the surface area of each isomer. The more spherical the shape of the isomer, the less surface area is in contact between molecules and less energy is required to separate them. These isomers will have a lower boiling point than the more linear shaped isomers. The difference in chemical reactivity may be less notable for hydrocarbons since the bond strengths will be much the same regardless of their configuration. For constitutional isomers having functional groups attached, there can be a drastic difference in chemical reactivity. 13. + H H N H O C N – H Answers to Section 1.2 Review Questions (Student textbook page 41) 1. A homologous series is a specific series of compounds in which each member differs from the next by an additional specific structural unit. For example, C2H6 and C3H8 differ by CH2 2. ethane C2H6 H H C H H C H H 3. prefix: 2-methyl; root: hept; suffix: ane Each name has three parts, the prefix, the root, and the suffix. The root indicates the number of carbon atoms in the longest continuous chain of carbon atoms. The prefix indicates the position(s) and name(s) of any branches attached to the main chain. The suffix indicates the series to which the compound belongs. 4. a. CnH2n+2 b. CnH2n c. CnH2n–2 5. Examples are: • octane, major component of gasoline, CH3CH2CH2CH2CH2CH2CH2CH3 • butane, lighter fluid, CH3CH2CH2CH3 • nonane, component of camp stove fuel, CH3CH2CH2CH2CH2CH2CH2CH2CH3 • toluene, used in paint thinner, C6H5(CH3) Unit 1 Part A • MHR 5 6. Both groups are made up of the elements carbon and hydrogen. Saturated hydrocarbons have single bonds between carbon atoms so that each carbon is bonded to four atoms, the maximum number for carbon. Unsaturated hydrocarbons have at least one double bond or triple bond between two carbon atoms. Comparing the boiling points of alkanes, alkenes and alkynes with similar number of carbon atoms, the alkenes have the lowest and the alkynes the highest. 7. a. 3-methylheptane b. 2-methylpropene c. 2,3-dimethylcyclohexene d. 2-ethyl-1,3-dimethylbenzene 8. a. CH C CH CH CH 3 3 CH3 b. HC H3CH2C C C CH3 CH3 CH2CH2CH3 CH C H3C c. CH2 CH2CH3 CH3 CH CH CH2 CH3 CH3 CH3 CH2 CH3 CH CH2 CH CH2 Answers to Section 1.3 Review Questions (Student textbook page 82) 1. Alcohols can be used for solvents, antifreezes, fuels, antiseptics. Only one, ethanol, can be used in beverages. They can also be used as starting materials for the synthesis of industrial compounds. CH3 CH3 d. 12. a. Hormones such as estrogen and testosterone have cyclic rings. b. Flavours such as vanilla are aromatics. 13 a. There is only one spot for the triple bond which is between carbons one and two because carbon atoms are always numbered so that the double bond is nearest C1. b. There is only one double bond and multiple bonds in cyclic compounds always begin at the number one carbon. 14. The electrons in the second bond of double bonds are shared equally among all the carbon atoms and are termed delocalized. If there were alternating single and double bonds, the molecule would have unequal bond lengths. The lengths of all of the bonds in benzene are all the same and between the lengths of typical single and double bonds. CH2 CH2 CH3 9. a. 2. Unlike propane, which would be a gas at room temperature, propan-1-ol would be a liquid at room temperature and would only combust with the oxygen in the air on the surface of the liquid. 3. Ethanol is more polar than tetrachloroethene and would not dissolve non-polar molecules as well. Ethanol would not evaporate as well and would therefore take more energy to recover. 4. Comparing Aldehydes and Ketones Aldehydes Ketones Structure formyl group at end of carbon chain carbonyl group on a nonterminal carbon atom Naming root: indicates number of carbon atoms in longest chain suffix: –al root: indicates number of carbon atoms in longest chain suffix: position number of carbonyl group, –one Physical properties • small – soluble in water • polar • < 15 carbon atoms – liquid • > 15 carbon atoms – waxy solids • small – soluble in water • polar • < 15 carbon atoms – liquid • > 15 carbon atoms – waxy solids b. c. d. 10. Test their boiling points: hex-1-ene < hexane < hex-1-yne < cyclohexane 11. CnH2n; The alkenes with one double bond also have this general formula. 6 MHR • Chemistry 12 Solutions Manual 978-0-07-106042-4 5. Butter, cheese, and vomit may contain partially digested fats. 6. The carboxyl group, –COOH, found in carboxylic acids would conduct electric current and turn litmus red. 7. a. Propan-1-ol and ethanoic acid b. Ethanol and propan-1-amine 8. a. One would expect alcohols, primary and secondary amines, carboxylic acids, and primary and secondary amides to form hydrogen bonds with identical molecules. b. They would be more soluble in polar solvents such as water and have higher melting and boiling points as compared to similar sized molecules with other functional groups. 9. a. Three ethers could have this formula: 1-methoxypropane, ethoxyethane, 2-methoxypropane. Ethers have the general formula R–O–R’. b. Three alcohols could have this formula: butan-1-ol, butan-2-ol and 2-methylpropan-1-ol. c. The ethers would have lower melting points and boiling points than the alcohols. The alcohols would be more soluble in polar solvents such as water. 10 a. hexan–3–ol b. 3-methylpentane-2,2-diol c. 1-2-dichloro-1-fluoro-2-methylpropane 11 a. OH b. OH HO c. Answers to Practice Problems For full solutions to Practice Problems, see Part B of this Solutions Manual. (Student textbook page 19) 1. 2-methylpropane 2. 2,2-dimethylpentane 3. 5-ethyl-3,4-dimethylnonane 4. 3,3,5-trimethylheptane 5. 2,2,5-trimethylhexane 6. 2-methylbutane 7. dimethylpropane 8. 2,2,4,4-tetramethylhexane 9. pentane 10. 2,3-dimethylpentane 11. 3,3-dimethylheptane (Student textbook page 21) 12. CH3 H3C 13. H3C CH2 C CH2 CH2 CH3 CH3 14. CH3 C CH CH2 CH2 CH2 CH2 CH3 CH3 CH2 CH2 O O e. CH3 H2C OH d. CH2 CH3 CH3 O HC CH3 15. (12) NH2 (13) (14) Unit 1 Part A • MHR 7 16. pentane 17. 4-ethyloctane (Student textbook page 27) 35. H3C CH CH CH2 18. 3,3-diethyl-4-methylhexane 36. 19. H H HH C HH H C C C C H H H H CH2 CH2 H3C CH C CH3 CH2 37. H CH3 CH2 CH2 CH3 CH3 H3C CH C CH CH2 CH3 H3C 20. H H H C H C H H C H C C C H H H H H H H H C C C C C C H H H H H H C HH C H H H C HH C H C 21. H H C 38. H H H C H H H C H H H H H H H C C C C C C C C H H H C H H H C H H H H H H H H C C H3C H CH3 CH3 CH CH CH C CH2 H2C CH3 CH CH CH3 CH2 CH CH CH2 39. 22. 4-ethyl-4-propylheptane (Student textbook page 26) 23. pent-2-ene c12_techart_c1-pp_ans21 24. 3-methylbut-1-ene 25. 4,4-dimethylhex-2-ene 26. 2-ethylpent-1-ene 27. 3,4-diethylhex-2-ene 28. but-1-ene 29. 5,6-dimethylhept-3-ene 30. 4-ethyl-3-methylhex-2-ene 40. hex-2-ene H3C CH2 41. 5-ethyloct-2-ene H3C CH2 33. 4-methylpent-2-ene 34. 2-ethyl-3-methylpent-1-ene 8 MHR • Chemistry 12 Solutions Manual 978-0-07-106042-4 HC CH2 42. 2-methylbut-2- ene CH3 31. 2,5-dimethyloct-3-ene 32. propene CH2 H3C CH C CH3 CH2 CH3 CH3 CH3 43. a. H H C HH H C C H b. H C d. H C C H H 52. but-1-yne 53. 4-methylpent-2-yne H H H C H HH C HH H C C C H H C H C 51. but-1-yne H 54. 3-ethyl-5-methyl-3-propylhex-1-yne (Student textbook page 34) 55. cyclopentane H H C H C HH H H 56. 1-ethyl-3-methylcyclobutane 57. 4-methylcycloheptene 58. 3-methyl-5-propylcyclopentene c12_techart_c1-pp_ans50d 59. 3-cyclopentyloctane 44. 3-ethyl-3-propyl-4-methylhex-1-ene 60. CH3 61. CH3 CH3 (Student textbook page 30) 45. hex-3-yne 62. CH3 46. 4-methylpent-1-yne 63. 47. 5-ethyloct-2-yne 48. 4,4,5-trimethylhex-1-yne 49. a. H3C C C b. CH3 CH3 HC C CH2 CH 64. CH C C C CH2 d. H3C CH3 HC CH2 C C CH CH2 c. CH2 CH2 CH3 68. 2,4-diphenyloctane HC 69. CH2 CH3 H3C 50. a. b. CH 67. 1-ethyl-3-propylbenzene CH3 CH2 CH3 66. 1,2,4-trimethylbenzene CH3 CH3 CH3 CH2 (Student textbook page 38) 65. methylbenzene, historically known as toluene CH3 CH3 H2C CH3 CH3 CH3 c. CH2 CH3 CH2 70. CH2 CH3 CH2 CH2 CH3 CH3 H3C CH3 Unit 1 Part A • MHR 9 71. H3C CH2 CH2 84. CH3 OH CH2 72. CH2 CH3 H2C CH3 (Student textbook page 49) 85. 2-fluorobutane CH2 CH3 86. 3-bromo-3-methylpentane H3C 87. 3-chloro-5-methylhexane CH3 73. CH3 CH2 CH3 H2C CH CH2 CH2 CH3 88. 1,3-dichloro-2-fluorobutane 89. 1,3-dibromo-2-chlorocyclohexane 90. CH2 CH2 CH H2C CH2 CH3 l 91. CH2 CH3 74. 1-ethyl-4-methylbenzene H2C CH2 F Cl 92. CH3 Br CH3 CH3 C CH CH2 CH3 CH3 93. H2C Cl CH3 H3C (Student textbook page 45) 75. butan-2-ol CH HC CH Br Br 94. 1,4-difluoro-2-propylcycloheptane 76. pentane-2,3-diol F 77. propan-2-ol 78. 3-methylbutane-1,3-diol 79. 6-phenyl-2-propylheptan-1-ol 80. 81. F OH H2C 95. a. 2-chlorobutane b. 3-bromo-4-chlorohexane c. 1,3-dichlorocyclopentane d. 2-chloro-3,3-dimethylbutane CH3 OH H2C CH2 CH3 82. (Student textbook page 52) 96. propanal OH HO CH2 83. CH2 H3C H3C CH2 CH CH2 HC CH3 CH3 OH CH HC 97. 2-methylbutanal 98. 3-ethyl-4-methylhexanal CH3 10 MHR • Chemistry 12 Solutions Manual 978-0-07-106042-4 99. 2,4-dibromopentanal CH3 100. C CH2 H 101. 110. CH3 O CH CH O 3 H3C CH3 H C CH3 O C CH2 111. C H3C O H 102. O CH3 H3C HC C CH3 112. The ketone group lies on a carbon attached to two other carbons H3and C therefore C CH2would never have a numerical assignment of 1. This compound does not exist. O H 103. CH2 113. The correct name CH3 is pentan-2-one. Numbering of the longest carbon chain gives the ketone group the H3number. C C CH2 lowest Cl H2C C O H 104. CH2 H3C CH2 CH3 C CH2 H2C CH3 H CH2 C O 105. a. The correct name is ethanal. The aldehyde group should be placed on the number 1 carbon (unless there are other higher priority functional groups also present such as carboxylic acids). It is not necessary to include a number in this case as it is assumed the aldehyde is on the first carbon. b. The correct name is 5-methylheptanal. The longest chain would include the ethyl group, and the methyl group would be a side branch. c. Since carbon only forms four bonds, an aldehyde could not be inside a cyclic hydrocarbon as well as having hydrogen and double-bonded oxygen. Therefore, this compound does not exist. d. Since the terminal carbon would need to have a hydrogen and a double-bonded oxygen, and be joined to the hydrocarbon chain, there would be no room for a fluorine to bond. This compound does not exist. 114. The correct name is 5-methyloctane-3,4-dione. Numbering should begin with giving the ketone 3 groups the lowest possible numbers. TheCH longest continuous chain containing these H3groups C C is eight CH2 carbons long. 115. Since carbon forms only four bonds and the linkage between carbons in the benzene ring is considered the intermediate of a single and double bond, the carbon atom with the ketone group would not be able to form a double bond with oxygen. This compound does not exist. (Student textbook page 61) 116. propanoic acid 117. 4-ethylhexanoic acid 118. O CH2 H3C 119. HO CH2 C CH2 C CH2 CH2 HC OH CH3 CH2 CH2 CH2 CH3 O 120. (Student textbook page 56) 106. butan-2-one CH3 O C CH2 CH C CH2 CH2 CH CH2 CH3 HO 107. 2-methylpentan-3-one 108. 3-ethyl-4-methyl-hexan-2-one 109. O 121. OH HO O CH2 C O Unit 1 Part A • MHR 11 122. The correct name is hexanoic acid. The carboxylic acid gets the lowest number on the longest hydrocarbon and is assumed to be on carbon 1. 123. Owing to carbon only being able to form four bonds, a carboxylic acid functional group would always be at the end of a hydrocarbon chain. This compound does not exist. 124. The correct name is 3-ethylheptanoic acid. Numbering should begin with giving the carboxylic acid groups the lowest possible numbers. The longest continuous chain containing these groups is seven carbons long. 125. Since carbon forms only four bonds, a carboxylic acid group could never be inside a cyclic hydrocarbon. This compound does not exist. (Student textbook page 69) 136. 1-ethoxypropane 137. 2-ethoxypropane 138. ethoxycyclohexane 139. H3C O CH2 CH3 140. CH3 H3C CH2 CH2 141. HC O CH2 H3C CH2 O HC CH2 CH3 CH3 CH CH2 CH3 CH3 142. (Student textbook page 65) 126. methylethanoate CH3 O HC CH2 CH2 CH2 CH2 CH3 127. ethylmethanoate 143. The correct name is methoxyethane. The root name should be the longest hydrocarbon chain. 128. butyl 3-chlorobutanoate 129. O CH2 H3C 130. O C CH3 CH2 CH3 O H3C CH2 O 131. C CH2 O CH2 O H3C 132. CH2 CH2 HC C CH3 O O 133. 146. The correct name is ethoxybenzene. It is assumed that the R′ group is first attached to the number 1 carbon of the benzene ring and it is not necessary to number it. 148. pentan-3-amine O 149. N-ethylbutan-2-amine F 150. N-methyl-N-propylhexan-2-amine 151. O H3C NH2 152. O 135. 145. The correct name is 2-methoxypentane. The numbering of the root name should be made to give the longest possible chain to which the R′ group is attached. (Student textbook page 74) 147. ethanamine O 134. 144. The correct name is 2-propoxybutane. The numbering of the root name should give the ether linkage the lowest number possible on its hydrocarbon chain. H3C O 153. O 12 MHR • Chemistry 12 Solutions Manual 978-0-07-106042-4 CH2 H2C NH2 CH2 CH2 NH CH2 CH2 CH2 CH2 HC CH2 CH3 NH2 CH3 Answers to Chapter 1 Review Questions 154. H3C CH2 CH2 155. CH2 CH H3C N CH2 CH2 CH3 CH3 (Student textbook pages 87-91) 1. b 2. c NH2 3. a 4. d 156. 5. e NH 6. d 7. b 157. 8. d N 9. e 10. e 158. 11. a N 12. c 13. e 14. b (Student textbook page 79) 159. methanamide 15. Carbon can form four bonds as it has four unpaired electrons. It also has intermediate electronegativity which prevents it from forming singular ions. This allows it forms covalent bonds which can continue in chains. 160. 3-ethylhexanamide 161. N-propylpentanamide 162. N,N-dimethylbutanamide 163. H 3C O 16. Isomers are molecules with the same molecular formula but their atoms are in a different arrangement NH2 17. Stereoisomers have the same molecular formula and connectivity but different three-dimensional arrangement of their atoms in space. Constitutional isomers are molecules that have the same molecular formula but have different connections between the atoms. C 164. O H3C CH C NH2 H3C 165. O H3C CH2 CH2 CH2 CH2 C N H3C CH2 CH3 CH2 166. O H3C CH2 CH CH3 C N CH2 H2C CH3 167. propanamide 168. N-propyl-2,2-dimethylbutanamide 169. N,N-dimethyl-2-propylhexanamide CH2 CH3 18. Molecules with two different atoms or groups on both sides of a double bond can form cis/trans isomers. Cycloalkanes with two side-groups can also form cis/trans isomers. 19. Enantiomers have identical structures. Their physical and chemical properties are essentially the same. However they do affect plane polarized light differently and may react with certain other enantiomeric molecules differently. As well, enzymes are specific for one form of the isomer. 20. Saturated hydrocarbons have each carbon atom bonded to as many other atoms as possible. Unsaturated hydrocarbons contain at least one double or one triple bond so each carbon atom has less than the maximum atoms bonded to it. Unit 1 Part A • MHR 13 21. a. CnH2n+2 b. CnH2n c. CnH2n-2 d. CnH2n 22. They are all non-polar and therefore do not dissolve well in polar solvents such as water. 23. They are similar in that they are six-carbon rings. The difference is that the six carbons in cyclohexane are single bonded, whereas the carbons in benzene have bonds that are intermediate between single and double. The formula for cyclohexane is C6H12 whereas the formula for benzene is C6H6. 24. Ethanol dissolves in polar solvents; ethane is soluble in polar solvents. Ethanol has higher melting and boiling points compared to ethane. At room temperature, ethanol is a liquid and ethane is a gas. 25. Both aldehydes and ketones have carbon atoms double bonded to an oxygen atom (carbonyl groups). In aldehydes the carbon in the C=O bond is the terminal carbon of a chain and, therefore, has a formyl group, whereas in ketones the C=O is in the main carbon chain with a carbon atom bonded to it on each side 32. Boiling points could distinguish the two as C2H6 would be a gas at room temperature whereas C8H18 would be a liquid. 33. a. correct name is 3-ethyl-2-methylpentane b. correct name is 3-ethylhex-1-ene 34. The formula for hexane is C6H14, cyclohexane is C6H12 and benzene is C6H6 35. Some examples could be: paradichlorbenzene, C6H5Cl2, used as a moth repellant, phenylacetone, C6H5CH2 –CO–CH3, used to make amphetamines, benzyl alcohol, C6H5CH2OH, used to make perfumes, paints epoxy resins. 36. There are five constitutional isomers of C4H4 as shown below. Constitutional isomers can have single, double, or triple bonds as long as the number of atoms present allow for them. The but-2-ene could have diastereoiosmers but they are not constitutional isomers. H2C H2C CH CH3 H2C CH2 H2C CH2 CH3 CH CH 27. An amide is the product of a reaction between a carboxyl group, –COOH, and an amine, –NH2. CH2 CH CH2 28. These aromatic compounds were found in naturally occurring plants and the original names were often taken from those sources. CH2 26. An ester is the product of the reaction between carboxyl, –COOH, and hydroxyl, –OH, functional groups. 29. a. CH4 — A carbon atom cannot bond to more than ­­ four atoms. b. C2H6 — Alkanes must have 2n+2 hydrogen atoms. c. hexane C6H14, or cyclohexane C6H12 As above. d. CH4 — Pure alkanes do not contain oxygen atoms. 30. Enantiomers, or optical isomers, are nonsuperimposable mirror images of each other. Four different atoms or functional groups must be bonded to the central carbon atom to form enantiomers. The mirror images of CH2BrF would be superimposable 31. CH2Br2 can form cis/trans isomers if the two bromine atoms are not on the same carbon atom. The molecule C2H2Br2Cl2 would have single bonds between the carbon atoms that can rotate freely. The molecule C2HI would have a triple bond between the carbons and would have a linear arrangement, with the H and I atoms 180° to one another. 14 MHR • Chemistry 12 Solutions Manual 978-0-07-106042-4 CH3 CH3 CH3 C CH3 37. a. Volatile organic compounds are organic compounds that have a vapour pressure high enough to evaporate and produce part per billion levels in the atmosphere. b. There are many beneficial uses: fuels, solvents, refrigerants, anaesthetics, etc. Their drawbacks include: contributing to global warming, creation of smog, destroying the ozone layer, and they are often are toxic at elevated levels. c. Examples of naturally occurring VOC’s are natural gas, methane, emitted from decomposition of animals as well isoprene, 2-methylbuta-1,3-diene emitted from forests. 2-methylbuta-1,3-diene CH2=C(CH3)–CH=CH2 Examples of anthropogenic sources are tetrachlorethane, low molecular weight petroleum derivatives (eg. hexanes, octanes) and formaldehyde (methanal). 38. The molecule can form an enantiomer. There are four different groups (methyl, hydroxyl, carboxyl, and hydrogen) around the second carbon atom and can therefore form a different mirror image. 39. Design an experiment to determine the boiling point of each compound. Ethane would have low boiling point, be a gas at room temperature and be poorly soluble in a polar solvent such as water as ethane is non-polar. Ethanol would have a higher boiling point, be a liquid at room temperature at be soluble in water due to the polar alcohol group. Ethanoic acid would be soluble in water and have an even higher boiling point than ethanol due to the two very electronegative oxygen atoms in the carboxyl functional group. Ethanoic acid could also conduct electric current. 40. a. hexane-3,4-diol b. 2-chloro-3,4-dimethylpentane c. 3-ethyl-6-methyldecan-2-one d. 3,3-dimethylpentan-2-one 41. Report should follow the guidelines for report writing, using proper grammar, and spelling, and identification of sources of information. Some inorganic greenhouse gases are CO2, N2O (nitrous oxide), water, and O3 (ozone). Examples of organic greenhouse gases are CH4 (methane), trichlorofluoromethane and dichlorodifluoroethane. Inorganic molecules such as carbon dioxide and water are much more abundant in the atmosphere and the production of CO2 by humans is much more prevalent. 42. a. Boiling Point vs Number of Carbon Atoms Boiling Point (°C) 200 100 Decane Nonane Hexane Pentane 0 –100 –200 Octane Heptane c. It should be mainly soluble in non-polar solvents due to the long hydrocarbon chain and insoluble in water. d. It should form constitutional (structural) as well as cis/trans diastereomers. There is no chiral centre (carbon atom bonded to four different atoms or groups) for enantiomers (optical isomers) 44. a. 2-methylbutanoic acid b. 7-methyl-7-phenylnonan-3-one c. ethylpentanoate d. N-methyl-N-propylbutanamine 45. a. From lowest to highest boiling points the molecules would be: ethane (-89°C), methoxymethane (-23°C), ethanamine (17°C), ethanoic acid (118oC), ethanamide (222°C). b. The molecules of these four compounds are about the same size and the amount of dispersion forces between molecules will be about the same. All except ethane are polar molecules and will experience dipole-dipole attractions between molecules. The greatest factor affecting the boiling point would be the amount of hydrogen bonding between molecules. Methoxymethane does not form hydrogen bonds and has the lowest boiling point. Ethanamine can form hydrogen bonds between molecules however nitrogen is not as electronegative as the oxygen atoms in ethanoic acid so the degree of hydrogen bonding is less in ethanamine. Ethanamine has a lower boiling point than ethanoic acid. Ethanamide has both electronegative oxygen and nitrogen atoms and the highest amount of hydrogen bonding would be expected between molecules of this compound. c. Ethanoic acid and ethanamide are liquids at room temperature and the other are gases. Butane Propane Ethane Methane b. C11H24 about 200°C; C12H26 about 215°C 43. a. Aromatic (phenyl), alkene and alcohol. b. It should have a high boiling point (eg. over 400°C) due to the long hydrocarbon chain and polar alcohol groups. It c12_techart_c1-cr_ans42a would be a liquid due to the unsaturation. Unit 1 Part A • MHR 15 46. Name Structure Saccharin Functional Groups O OH O HO OH Mannitol 300X sweeter than sucrose bitter; USDA has removed carcinogen warnings haloalkane, alcohol, ethers 600x sweeter than sucrose; stable at hot and cold temperatures; good for baking non-cited alcohols doesn’t cause tooth decay; does not affect insulin levels; can be extracted from plant products; medicinal uses; not hygroscopic amino group, ester linkage, amide linkage, carboxyl group 160 - 220 times sweeter than sucrose; does not cause tooth decay; does not affect insulin levels; is metabolized like other amino acids O O Cl Cl Cl O O OH OH OH OH OH OH OH OH Aspartame 47. a. H H H H C H H3C C H CH2 C Drawbacks (Cons) ketone, aromatic, amine, (sulfoxyl) NH S Sucralose Benefits (Pros) H C O C H harmful to people with rare genetic disease, PKU (phenylketoneurea) 48. a. NOTE: The name is invalid and should be 3,4-dimethylheptane 3, 4-dimethylheptane H H CH CH2 CH b. OH OH b. Several constitutional isomers can form by changing the location of the double bond and the hydroxyl group. Many more could be formed because it could form carboxylic acids, ketones, and aldehydes. The double bond allows for the formation of diasteriomers. O O O NH OH NH2 O 16 MHR • Chemistry 12 Solutions Manual 978-0-07-106042-4 c. 49. a. 1,3-dichloro-2-fluoro-2-methylpentane b. butanal c. 3-amino-3-hydroxybutan-2-one 50. a. methanal b. methylbenzene c. 1,2-dimethylbenzene d. phenylamine e. trichloromethane 51. Answers should include the key terms and concepts shown on page 86. Graphic organizer could be a main idea web, a spider map, or a concept map. 52. a. Herbicides are used to kill unwanted plants for aesthetic purposes and to increase crop yields in agriculture. b. The molecule shown is glyophosate or N-phosphonomethyl amino acetic acid. Reasons would be that it has no chlorine substituents expected in the name of 2,4-D and the presence of amino and carboxylic acid groups (as well as a phosphorus atom) present in the IUPAC name for glyophosate. c. General consensus would be that glyophosates would be less harmful to the environment due shorter persistence and fewer medical side effects to this date. d. Some alternatives around the home are to use mulch, plant native plants that would compete better with weeds, pull weeds by hand and use less controversial household chemicals such as acetic acid (vinegar), boiling water, rubbing alcohol or corn gluten to remove undesirable plants. Other reasonable alternatives are possible. 53. a. Putrescine would have the name butan-1,4-diamine and cadaverine would be pentan-1,5-diamine. b. Rotting flesh smells putrid and another term for an animal corpse is a cadaver. The suffix “ine” indicates an amino group. c. Substances such as citric acid found in citric fruits or other carboxylic acids would react with the slightly basic amine group and form salts which are nonvolatile. 54. a. N,N-diethyl-3-methylbenzamide b. The common name, DEET, comes from the letters “dee” to represent diethyl, and the “t” in toluene. It is simpler for everyday use. c. It would dissolve in non-polar or slightly polar solvents. d. WHMIS symbols would poisonous and infectious causing other toxic effects (if inhaled or long time exposure); poisonous and infectious with immediate side effects (if ingested). It is also flammable. e. Risks Benefits Poisonous if taken internally Personal comfort by preventing painful and distracting parasites from biting When sold as an aerosol, must be used with caution and disposed of in a safe manner. Controls insects that carry disease Insects can develop immunity to the compound. Persists in the environment affecting non-harmful, beneficial insects f. Possible alternatives would be: wearing light clothing, covering exposed skin, restricting outdoor activities during peak insect hours, removing environments that breed insects (standing water) or attract certain insects (CO2, certain perfumes), using naturally derived insect repellents (e.g., cinnamon), 55. Reduce fuel spillage, take public transit, have automobiles tuned up and emissions systems in good working order, reduce leaks of heating, cooking and transportation fuels, reduce unnecessary mechanized travel. 56. a. The difference in boiling point is due to the difference in the intermolecular attraction between molecules. The –OH group in methanol is very polar, which allows for the formation of hydrogen bonds with neighbouring molecules. Methanal is slightly polar and can form dipoledipole interactions but has no hydrogen bonding. Since there is less attraction between molecules of methanal, this compound has a lower boiling point. b. Formaldehyde is an aqueous solution of methanal. 57. a. Saturated fats have higher melting points than unsaturated and are therefore solids at room temperature whereas unsaturated fats are usually liquid. Unit 1 Part A • MHR 17 b. Cis fats are unsaturated and have the hydrocarbon chains on the same side of the double bonds whereas trans unsaturated fats have them on opposite sides. cis form Answers to Chapter 1 Self-Assessment Questions (Student textbook pages 92-3) 1. a 2. c 3. e 4. e 5. d 6. c trans form 7. a c. The unsaturated fats are softer and less likely to form a hard layer lining the arteries which leads to strokes and heart attacks. Also the sites of double bonds in unsaturated fats are more reactive than the single bonds between carbons in the saturated fats. 58. a. adrenaline: C9H13NO3; amphetamine: C9H13N b. Both have a phenyl group, C6H5, and an amine, NH2 group, adrenaline has –OH groups that are not c12_techart_c1-cr_ans57 present in amphetamines. c. Epinephrine (adrenaline) constricts blood vessels and dilates air passages, which reverses the effects of an anaphylactic shock. d. Amphetamines increase alertness and concentration. 8. c 9. c 10. e 11. The molecules are not constitutional isomers as they are the same molecule just rotated and drawn differently. 12. Two pairs are possible cis-hex-2-ene 59. a. trans-hex-2-ene and Limonene cis-hex-3-ene CH3 HC H2C H H2C C C C CH2 CH2 chiral/optical centre carbon CH3 b. One would expect it to be found in citrus fruits. c. The R-(+) limonene smells of oranges and the S-(–) limonene smells of lemony turpentine. d. It can be used as an industrial solvent because it is less volatile and non-toxic than chlorofluorocarbons and methyl ethyl ketone. e. As it can be extracted from orange peels and is thus a renewable resource. It is also biodegradable. 18 MHR • Chemistry 12 Solutions Manual 978-0-07-106042-4 trans-hex-3-ene 13. a. The root must be the longest continuous chain. The correct name is 2-methylbutane. b. Numbering of the carbon atoms in the main chain of an alkane must begin at the end that will give the side groups the lowest possible numbers. The correct name is 2,3-dimethylpentane. c. This molecule is named correctly. d. The numbering of the carbon atoms in the main chain of an alkene must begin at the end nearest the double bond. The correct name is 5-ethyl-6methylhept-3-ene. 14. a. Solid alkanes could be found in waxes, asphalt and greases. The molecules would be over 18 carbon atoms long. b. Liquid alkanes could be found in gasoline, lubricating oils and heating fuels such as kerosene. The molecules would be between 5–22 carbon atoms long. c. Gaseous alkanes could be found in natural gas, propane and butane used for heating and cooking. The molecules would be 1–4 carbon atoms long. b. CH3 CH3 eg. cyclohexane 3-methylpent-1-yne c. Example:eg.3-methylpent-1-yne; C6H10 d. cyclohexane d. Example: cyclohexene; C6H10 e. benzene C H e. Example: benzene; 6 6 16. Benzene is not an alkane because the carbon atoms are bonded to only three other atoms. Each carbon atom is bonded to only one hydrogen atom. The ring in the centre of the benzene diagram represents the six-delocalized electrons that are shared equally among atoms. This resonance hybrid has equal bond lengths halfway between a single and double bond. 17. a. 3-methylbutanoic acid b. N,N-dimethylpropan-2-amine 18. a. CH2 c. CH3 C NH CH CH2 CH3 CH2 CH3 CH2 CH3 CH2 CH2 CH3 19. Both esters and amides have a carbonyl group (C=O) but esters have an extra oxygen bonded to this carbon whereas amides have a nitrogen. They both can be thought of as the product between a carboxylic acid with another molecule. The other molecule needed to form an ester is an alcohol whereas the other molecule needed to form an amide is an amine. The alkyl group that was derived from the carboxylic acid would get the prefix and the alcohol and amine derivatives would get the suffix. Esters end in “oate” and amides end in “amide.” Primary and secondary amides will have high melting and boiling points and will often be solids because they can hydrogen bond with one another. Esters are polar but no hydrogen bonding can occur. The melting points are therefore lower than the amides of similar size. At room temperature many are liquids. The longer chain esters may be waxy solids. 20. a. They IUPAC name would be ethanedioic acid. b. It would be a solid at room temperature due to its ability to form multiple hydrogen bonds with other oxalic acid molecules. c. It would be soluble in polar solvents such as water due to its ability to form hydrogen bonds with the solvent 21. propan-1-ol propan-2-ol methoxyethane O O C O O HO CH3 CH CH3 eg. 2-methylpentane 15. a. Example: 2-methylpentane; C6H14 b. Example: cyclohexane; C6H12 CH2 22. No. Cyclopentane has the chemical formula C5H10 while pentane has the chemical formula C5H12. 23. Use BLM A-32 Presentation Rubric or BLM A-36 Multimedia Presentation to assess answers. 24. a. OH CH3 CH CH3 Unit 1 Part A • MHR 19 b. The –OH group in the alcohol can hydrogen bond with the water whereas the non-polar propyl group can join with the non-polar molecules c. Keeping the gas tank as full as possible and having a proper gas cap will prevent humid air from entering the tank. 25. a. The source for most of the hydrocarbons we use are from fossil fuels such as crude oil, natural gas and coal. b. Some problems associated with the source are oil spills, acid rain, explosions and the fact that it is non-renewable, accumulation of CO2 which is a greenhouse gas associated with global warming. c. Other sources could be using plants and bacteria to produce biodiesel and ethanol. (Student textbook page 107) 7. A substitution reaction occurs when the reactants are an alkane with a substituent of a halogen or a hydroxyl group, and the other reactant is H−X, or OH−. A condensation reaction can occur when the reactants are a carboxylic acid and an ammonia or amine. An esterification reaction occurs when the reactants are a carboxylic acid and an alcohol. 8. condensation reactions two molecules combine to form one larger molecule and one very small molecule which is usually water esterification reaction Chapter 2 Reactions of Organic Compounds a special case of a condensation reaction in which one reactant is an alcohol and the other is a carboxylic acid and the products are an ester and a water molecule Answers to Learning Check Questions (Student textbook page 102) 1. Both are examples of reactions of organic compounds. In an addition reaction, atoms are added to an organic compound at the site of a double or triple bond. In elimination reactions, atoms are removed from an organic molecule and a double bond is formed. Elimination reactions are the opposite of addition reactions. 2. They act as catalysts. 3. a. More than one product is possible with an asymmetric molecule. b. The major product occurs when the hydrogen atom is removed from the carbon atom that has the most carbon-carbon bonds. 4. The hydrogen atoms of the small molecule will attach to the carbon of a double bond that is already bonded to the most hydrogen atoms. The rule is used when two products can be formed from an addition reaction. 5. No, if there is a limited amount of X–X, then a substituted alkene will be produced. 6. Carbons can only have up to four bonds, and alkanes are already fully saturated. Therefore, the carbons cannot accept any more bonding partners. Alkenes and alkynes are unsaturated and can break a double or triple bond in order to bond with another element/ compound. 20 MHR • Chemistry 12 Solutions Manual 978-0-07-106042-4 9. They are reactions that form large biomolecules such as proteins, which are essential to living things. 10. acetylsalicylic acid, artificial flavours, and artificial aromas 11. Nine esters: Each alcohol will react with each of the carboxylic acids. The ester names are methyl methanoate, methyl ethanoate, methyl propanoate, ethyl methanoate, ethyl ethanoate, ethyl propanoate, propyl methanoate, propyl ethanoate, and propyl propanoate. 12. a. Esterification: The product is an ester. b. condensation: The product is an amide. c. substitution: A halogen could replace an hydroxyl group on the alcohol. (Student textbook page 120) 13. A polymer is a large, long-chain molecule with repeating units of small molecules called monomers. Some uses are plastics, adhesives, and chewing gum. 14. • Addition polymerization only—Monomers are combined by addition reactions. For example, the monomers could be alkenes. In the polymer, the former double bonds have become single bonds. • Addition and condensation polymerization—In both types of reactions, small molecules link to form long chains of very large molecules. • Condensation polymerization—Monomers have two functional groups which can undergo condensation reactions with groups on the other monomers. For example, the monomers might have both a carboxyl group of one end and an alcohol group on the other end. The carboxyl group of one monomer reacts with the alcohol group on another monomer to form an ester linkage. The result is a polyester. 15. polyurethane 16. Addition polymer: There are fewer double bonds in the polymer than in the monomers. No molecules, other than the polymer, are formed. Answers to Caption Questions Figure 2.3 (Student textbook page 97): The carbon atoms in the product are bonded to more atoms than the carbon atoms in the organic reactant. Figure 2.14 (Student textbook page 116): Possible responses: train cars linked together to form a long train, linking building blocks together Answers to Section 2.1 Review Questions (Student textbook page 115) 1. a. oxidation b. esterification c. elimination NB: First product should be CH2=CH2. 17. amino acids 2. a. ethylhexanoate + water b. methanoic acid c. 2-bromopropane + water d. bromobenzene + hydrobromic acid e. methanoic acid 18. A polymer containing cross-links is stronger and less flexible than a straight chain polymer. 3. Substitution reaction: haloalkane + OH− → alcohol + halide ion Condensation polymer: A small molecule (usually water) is released with the formation of each monomer-monomer linkage. (Student textbook page 124) 19. The petroleum is separated into classes of hydrocarbons according to size in a process called fractional distillation. A variety of organic reactions are used to convert the hydrocarbons into compounds needed as starting materials for the production of compounds that are useful such as plastics. 20. The petrochemicals are very useful in industry. 21. Ethene is reacted with chlorine to make dichloroethane. This is then cracked to produce HCl and chloroethene. Chloroethene is reacted in an addition polymerization reaction to make PVC. 22. Advantages: PVC is very useful for industrial products such as windows, piping, and doors. Disadvantage: The monomer, vinyl chloride, is a carcinogen. 23. Dioxins are chlorinated aromatic hydrocarbons that are toxic by-products from the production and disposal by incineration of PVC. 24. Recycle, Reduce usage, Reuse plastics; purchase degradable plastics Oxidation reaction: alcohol + [O] → aldehyde Oxidation reaction: aldehyde + [O] → carboxylic acid 4. Addition reactions and elimination reactions can result in more than one product if the reactants are asymmetric. In addition reactions, the H atom will bond to the carbon with the most H atoms already bonded to it. In elimination reactions, the H atom will be removed from the carbon with the most carboncarbon bonds. 5. a. C3H8(g) + 5O2(g) → 3CO2(g) + 4H2O(ℓ) b. 2C4H10(ℓ) + 13O2(g) → 8CO2(g) + 10H2O(ℓ) c. C13H28(ℓ) + 20O2(g) → 13CO2(g) + 14H2O(ℓ) 6. a. CH2=CH2−CH3 + H2O b. CH3− HC(Cl)−HC(Cl)−CH3 c. major product CH3−CH(Br)−CH3 minor product CH2(Br) −CH2−CH3 7. It is a hydrolysis reaction. CH3− CH(CH3)−CH2−COOH + HO−CH2−CH3 8. a. CH3OH b. CH3−CO−CH3 Unit 1 Part A • MHR 21 9. major product: 2-methyl-2-bromooctane, H3C−C(Br)(CH3)−CH2−(CH2)4−CH3 5. a. polyamide O minor product: 2-methyl-3-bromooctane, H3C−CH(CH3)−CH2(Br) −(CH2)4−CH3 HO (Student textbook page 127) 1. a. Natural polymers are found in living things whereas synthetic polymers are manufactured by chemical processes outside of living things. Both are long chains made up of similar or identical monomer units. b. Three examples of naturally occurring polymers are starch (a polysaccharide), proteins, and DNA. Three examples of synthetic polymers are polystyrene, polyvinylchloride, polyethylene. c. The starch monomer is glucose. Protein monomers are amino acids. DNA monomers are nucleotides, which consist of a nitrogen base, a five-carbon sugar, and a phosphate group. The polystyrene monomer is styrene (phenylethene). The monomer of polyvinyl chloride is vinyl chloride (chloroethene). The monomer of polyethylene is ethylene (ethene). 2. Addition and condensation reactions. 3. a. The hydroxyl group (−OH) of an alcohol and the carboxyl group (−COOH) group of a carboxylic acid react to form an ester bond. b. The carboxyl group (−COOH) of a carboxylic acid and an amino group (−NH2) of an amine react to form an amide bond. 4. a. (i) During the production of synthetic polymers, harmful by-products are often produced. (ii) Many synthetic polymers remain in the environment for long periods of time. (iii) The incineration of many synthetic polymers produces harmful, toxic products. b. Synthetic polymers are used to mass produce a wide variety of items that are durable and long lasting and things that could not be made from natural reactants. c. Possible answer: Yes. Our technological society has become dependent on many of the synthetic polymers for variety of applications. However, we need to find ways to minimize risks. 22 MHR • Chemistry 12 Solutions Manual 978-0-07-106042-4 (CH2)4 C C OH H2N (CH2)6 NH2 CH NH2 b. polyamide 10. Carbon monoxide, is an odourless, colourless, poisonous gas, is a product of incomplete combustion. Answers to Section 2.2 Review Questions O O C HO O CH2 C OH H2N CH2 CH2 c. polyester O HO CH2 CH2 OH HO O C CH2 OH C 6. a. addition ... CH2 CH2 CH2 CH2 ... CH2 b. addition ... CH2 CH CH2 CH CH2 ... CH c. condensation O ... C O (CH2)3 C O NH CH NH C O (CH2)3 C NH CH3 CH NH ... CH3 d. esterification ...O O O C C O CH2 O O O C C 7. Example: crude oil fractional distillation ethane ethene polymerization polyethylene O CH2 cracking at 800ºC Answers to Practice Problems For full solutions to Practice Problems, see Part B of this Solutions Manual. (Student textbook pages 99-100) 1. H3C—CH2—CH2—CH3 2. a. H3C−CH2 −C(Br)=C(Br)−CH3 b. H3C−CH2 −C(Br)2−C(Br)2−CH3 3. The product is iodoethane. Only one product is possible because if iodine (I) is added to carbon 1 or carbon 2, the same product is formed. 4. CH3−CH(Cl)−CH(Cl)−CH2−CH3 ... 5. most abundant 11. methylcyclohexene + hydrobromic → acid CH CH2 OH CH CH3 CH3 CH CH 3 CH2 CH CH3 (Student textbook page 102) OH 12. CH3 CH CH2 CH2 OH CH2 CH3 CH CH 3 CH2 CH2 CH2 CH3 CH3 CH CH CH2 CH3 CH3 Br CH3 CH CH2 CH CH3 CH3 7. a. Br H C C C H H H H + HOCH2CH3 + NaCl 14. In addition to the HOCH2CH3 and NaBr which will always be products, the original 3-bromo-2methylpentane could form three different products. These products are 2-methylpent-2-ene, cis-2methylpent-3-ene, and trans-2-methylpent-3-ene. 15. Water will always be a product. The reactant, 2-methylpentan-3-ol can be converted to any or the three products, 2-methylpent-2-ene, cis-2-methylpent3-ene, or trans-2-methylpent-3-ene. 16. Sodium bromide and ethanol will always be products. The reactant, 3-methyl-2-iodibutane can be converted into 2-methylbut-2-ene or 3-methylbut-1-ene. b. most abundant 17. The major product will be 2,4-dimethylcyclohexene. CH3 ICH3 18. The major product will be 1-ethylcyclopentene. I 19. The possible reactants are butan-1-ol or butan -2-ol. least abundant CH3 20. The possible reactants are CH3 CH3 I I 8. a. CH2 + H2O 13. 6. neither is preferred over the other CH3 C CH3 H Br Br → CH3 CH3 least abundant CH CH x CH3 or OH CH2 CH2 CH3 x CH3 CH2 C CH2 CH2 CH3 CH3 b. CH2 Cl CH3 9. a. H2C=CH—CH2—CH3, or H3C—CH=CH—CH3, or HC≡C—CH2—CH3, or H3C—C≡C—CH3 b. CH2=CH—CH2—CH3 10. HBr + OH CH3 CH O CH2 CH3 X represents one of four possible elements: F, Cl, Br, or I. 21. The major product would be cyclobutene. 22. Note: NaOH should be deleted; reactant should be + NaOCH2CH3. The final products would be but-1-yne, HC≡C−CH2CH3, and but-2-yne, H3C−C≡C−CH3. SO3H Unit 1 Part A • MHR 23 (Student textbook page 104) 23. This reaction is not specific and, depending on the amount of chlorine present, a chlorine atom could replace any or all of the hydrogen atoms. 40. methanol and salicylic acid CH3 24. There are nine possible products. 25. CH3 CH O CH3 CH3 CH2 CH2 C CH2 OH + HO C CH2 CH3 + Cl− CH3 OH A base such as NaOCH2CH3 would give an elimination reaction but a hydroxide ion results in a substitution reaction. H23C CHC2 CH CCH2OH + HO CH2 CH2 (Student textbook page 113) 43. oxidation 44. reduction 45. reduction 30. Note: FeBr2 should be FeBr3 46. oxidation 47. addition and reduction 48. esterification and condensation 31. CH3CH2CH3 + Br2 49. CH4 + 2OCH 2 → CO2 + 2H2O + energy 32. 3 CH3 CH 50. C4H8 + 6O2 → 4CO2 + 4H2O + energy H3C C CH2 51. C3H8 + 5O2 → 3CO2 + 4H2O + energy CH2Cl + OH− CH3 52. C6H12O6 + 6O2 →6CO2 + 6H2O + energy (Student textbook page 108-9) 33. condensation reaction (Student textbook page 121) 53. addition 34. esterification reaction 54. addition 35. esterification reaction 55. condensation 36. esterification reaction 56. polyamide 37. condensation reaction H2N 38. ethanoic acid and octanol O CH3 C OH + HO CH2 (CH2)6 CH3 CH2 C HO CH2 NH2 CH3 O C 2)C6 C H3(CH CH2 OH C 57. polyester O CH2 CH2 O 39. butanoic acid and methanol CH3 CH CH3 42. butanoic acid + propan-1-ol CH3 O 28. 2-hydroxypropane + Cl− CH CH2 OH CH3 27. bromobenzene + HBr CH2 H H3C C CH2 acid + propan-1,2-diol 41. 3,3-dimethylheptanoic CH3 + H2O 26. bromobenzene + H2O CH3 C OH + HO CH3 Cl 29. OH O HO OH + HO CH3 C CH2 CH3 OH O H3C C CH2 O HO 24 MHR • Chemistry 12 Solutions Manual 978-0-07-106042-4 CH2 CH2 C OH CH2 CH3 58. polyester 13. e HO 14. a OH O O HO 15. a. CH2 C C OH C C CH2BrCH3 + NaOCH2CH3 → NaBr + HOCH2CH3 + CH2=CH2 n CH2=CH2 → - - - —CH2—CH2—CH2—CH2— - - - 60. CH2 O O C C O O C C O O CH2 CH2 O O CH2 CH2 O Z C C C ... CH2 CH CH2 CN CH CH2 CN CH ... 62. O ... O CH2 C O O CH2 C CH2 C R C (Student textbook pages 137-41) 1. c 2. d 3. a OH + H N R ammonia or amine C N Z + HOH amide O ... R Answers to Chapter 2 Review Questions Y water Look for an amide and water molecule as products. e. O O + O carboxylic acid CN C CH2 O C O CH2 Two compounds react to form two different compounds and the carbon atoms are bonded to the same number of atoms in the product and reactant. d. C O 61. C The carbon atoms in the organic product are bonded to fewer atoms than were the carbon atoms in the organic reactant. c. Y Z → C Z + A CO Y + A carry out addition polymerization on the ethene. O Y + Z The carbon atoms in the products are bonded to more atoms than the carbon atoms in the reactants. b. Y Z 59. First, treat the 1-bromoethane with NaOCH2CH3 to eliminate the bromine atom and a hydrogen atom resulting in ethene. Then C Y O C H2SO4 OH + HO carboxylic acid R alcohol C O + HOH ester water Look for an ester and water molecule as products. f. OH C O H + [O] C 4. d 5. d 6. a 7. c 8. b 9. b 10. b 11. a alcohol oxidizing agent O C aldehyde aldehyde or ketone O + H [O] oxidizing agent C OH carboxylic acid Look for carbon having more bonds to oxygen or fewer CHEM12_2.052A bonds to hydrogen. 12. d Unit 1 Part A • MHR 25 g. OH O C + aldehyde or ketone C C alkene [H] reducing agent + [H] reducing agent C H alcohol H H C C alkane Look for carbon having fewer bonds to oxygen or more bonds to hydrogen. h. hydrocarbon + O2 → CO2 + water + energy. Look for a hydrocarbon chain reacting with oxygen to form carbon dioxide and water. 16. Addition and elimination reactions are the opposite of each other. In addition reaction a double or triple bond between carbon atoms is lost and two new single carbon bonds with new atoms are formed. With elimination reactions two single bonds are lost CHEM12_2.069A and a double or triple bond between carbon atoms are formed while two atoms are eliminated from the reactant. 17. During an addition reaction use Markovnikov’s rule and add the hydrogen atom to the carbon atom already bonded to the most hydrogen atoms. During an elimination reaction remove the hydrogen from the carbon with the most bonds to other carbon atoms. 18. The reactions result in a large mixture of products. There are other ways to obtain the desired product. 19. Both reactions involve two large molecules coming together to form a large molecule and a small molecule (water). The difference is that esterification reactions always occur between an alcohol and a carboxylic acid. An esterification reaction is a special case of a more general condensation reaction. 20. A molecule is broken apart by adding the hydroxyl group from a water molecule to one side of a bond and the hydrogen atom of the water molecule to the other side of the bond. 21. When naming polymers add poly in front of the name of the monomer unit. In this case the monomer is called propylene (propene). 22. Polymers are long-chain molecules made with repeating units of small molecules and these natural molecules contain repeating units of small molecules. For example, proteins have repeating units of amino acids 26 MHR • Chemistry 12 Solutions Manual 978-0-07-106042-4 23. a. substitution b. elimination c. addition d. substitution e. addition f. elimination 24. a. oxidation, b. reduction, c. oxidation 25. a. esterification, b. condensation, c. hydrolysis 26. polyvinylacetate 27. polyesters – polymers in which the monomers are connected by ester bonds. Typically, one reactant monomer has an alcohol group on both ends and the other reactant monomer has a carboxyl group on both ends. polyesters and polyamides – Both are made through condensation polymerization reactions using two different monomers. Both use a carboxylic acid monomer as a reactant. Both reactions also produce a small molecule such as H2O. Both are durable products. polyamides – polymers in which the monomers are connected by amide linkages. One of the reactant monomers has an amine group on both ends and the other has a carboxyl group of both ends. 28. a. addition, b. condensation, c. addition 29. a. elimination, b. addition, c. combustion, d. substitution 30. a. butan-2-ol b. major product: 2-bromo-2-methylbutane minor product: 2-bromo-3-methylbutane c. propene d. major product: 3-methylpent-2-ene minor product: 3-methylpent-1-ene 31. a. propan-1-ol b. N-ethylpropanamide 32. a. Both of the compounds have an amine group and a carboxyl group. Any two molecules could react to form an amide bond. Therefore, although they are shown to alternate in the figure below, the two compounds will not necessarily alternate in the polymer. O O ... N ... N N N H H N. O O . .N O O . .. O b. N H N ... ... O ... ... O F F ... F F F F F F C C C C C C C C F F F F F F F F F F F C C C C C FC F F F F F F F c. O ... N F ... O O O .C. . NH CCH2 ... C 33. a. O CH2 HO CH2 C C NH O O O C 2 C C CH CH3 b. CH2 CH CH2 CH3 b. Br2(aq) WHMIS: Corrosive. Harmful if inhaled. Causes respiratory tract irritation and possible burns. Causes eye and skin irritation and possible burns. Wear gloves when making the bromine water. Work in a fume hood. c. addition d. H3C–CH(Br)−CH(Br)−CH3 37. • heat an alcohol in the presence of H2SO4 • react a haloalkane with a strong base such as sodium ethoxide NaOCH2CH3 38. a. hex-3-ene + HCl F F F F b. 3-methylbutanoic acid + propan-2-ol . . . C C c. 2-methylpropan-2-ol + HCl ... C C d. 2,5,-dimethylhex-2,4-diene F F F F e. methane + chlorine f. 2,3-dimethybutan-2-ol → 2,3-dimethylbutanal O O O 39. O O ... C NH CH CH NH • monomer CH3−CH=CH−CH3 ... C C NH CH2 CH2 NH CH2 NH CH2 NH ... C• polybutene −[−CH(CH C NH CH NH CH2 CH2 NH CH NH 2 2 )−CH(CH )−] − 3 3 n • solvent alkylethers, tertiary alcohols OH • acid catalyst WHMIS: 2-butene is a gas at room temperature, highly flammable, explosive with air mixture, inhalation can cause dizziness and unconsciousness, evaporation from skin can lead to frostbite, used face shield 2 40. Major product: 2-bromopropane, CH3—CHBr—CH3 c. O NH2 CH2 CH NH2 + HO C Minor product: 1-bromopropane, CH2Br—CH2—CH3 O CH2 C OH CH 34. A polyamide because the functional groups that react to form proteins are a carboxyl group and an amino group which form amide linkages. 35. a. 2C2H6 + 7O2 → 4CO2 + 6H2O b. 2C2H5OH + 6O2 →4CO2 + 6H2O 36. a. • use 2 fats and 2 oils • add equal portions of each fat and oil to separate test tubes • added a measured volume of bromine water to each test tube • shake gently or warm in a water bath while looking for a decrease in the intensity of the reddish colour of bromine water. 41. The product, 1-bromopropane, gives the impression that the reaction is a substitution reaction because a bromine atom is seen in place of a hydrogen atom. However, if it was a properly written equation, there would have to be an HBr in the products. Also, this method of substitution with alkanes is nonspecific and there would also be many other products. 42. 2 glucose → maltose + water 43. a. 2-phenylacetic acid + ethanol b. butyric acid + ethanol c. ethanoic acid + ethanol 44. Without the alcohol present, the esterification reaction shown will slow down and the reverse hydrolysis reaction will be favoured. 45. Degradable plastics are good because they break down over time when exposed to environmental conditions. It may be difficult to use across the world due to cost of manufacturing Unit 1 Part A • MHR 27 46. Hex-1-ene + HBr → 2-bromohexane + 1-bromohexane proteins – monomers are amino acids joined through Brcondensation reactions with amide linkages between Br the amino acids; include various functions of proteins CHCH 2 2 CH 2 2 CH 2 2 CH 2 2 CH 3 + 3 3 CH 2 2 CH 2 2 CH 2 2 CH 3 3 CH CHCH CH CH CH HBr→ →CHCH CH CH CH CH CH 3 +HBr in theCH human body such as building of muscle tissue, Br Br Br Br forming enzymes, hormones. DNA—monomers are → CH CH2 2 CH CH3 3 ++ HBr HBr → CH3 3 CH CH CH nucleotides, forms through condensation reactions CH2 2 CH CH2 2 CH CH2 2 CH CH 3 CH + 3+ CH CH CHCH 2 2 CH 2 the 2 2 CH 2 found 2 in 3nuclei, CH CH CH CH 2 CH 2 CH 2 cell 3 of nucleotides, codes for Br → 3-bromohexane hex-3-ene +Br HBr CH2 2 CH amino acid sequence to make a protein, controls cell development. Br Br CH2 2 CH CH2 2 CH CH2 2 CH CH2 2 CH CH2 2 CH CH3 3 ++CH 51. The wax candle is made up of very large alkanes. CHCH 3 3 CH 2 2 CH 2 2 CH 3 + 3 3 CH 2 2 CH 2 2 CH 2 2 CH 3 3 CH CH CHCH CHCH CH HBr→ →CHCH CH CH CHCH CH CH 3 +HBr Incomplete combustion of these alkanes results in Br Br the formation of the black soot. The black residue on the watch glass is soot which consists of incompletely → CH CH3 3 ++ HBr HBr → CH3 3 CH CH2 2 CH CH CH CH2 2 CH CH2 2 CH CH3 3 CH burned hydrocarbons. When HBr is added to hex-1-ene the Br can be added 52. to either carbon 1 or 2. Carbon 2 is preferred because it • PET is polyethylene terephthalate, a thermoplastic, is bonded to the most carbon atoms. polyester When HBr is added to hex-3-ene the Br can be added • monomer is ethylene terephthalate made from an to either carbon 3 or 4. However, because the molecule esterification reaction between ethylene glycol and is symmetrical, and carbon atoms are always numbered terephthalic acid such that the substituent has the lowest number, • repeating unit in the polymer is C10H8O4 adding to either carbon 3 or 4 results in the same • modification of product is accomplished through product, 3-bromohexane. a copolymerization reaction e.g. if cyclohexane 47. Some reactions can be categorized as two different dimethanol replaces ethylene glycol or if isophthalic reaction names because they fit both descriptions. For acid replaces terephthalatic acid, a softer product is example, the reduction of an alkene to an alkane can obtained also be thought of as an addition reaction (hydrogen 53. a. One estimate is 400 years. adding across the double bond) b. Plastic bags are not part of curbside recycling 48. The concept map should include the following types programs likely because of expense to get rid them. of reactions, with an example of each: addition, Individuals are reusing more and more. elimination, substitution, condensation, esterification, c. Much less plastic waste goes into landfill. It is also hydrolysis, oxidation, reduction, combustion (complete more economical. and incomplete), as well as addition and condensation d. Cleanliness and contamination can be a problem polymerization. The students should create categories especially if the bag is used for carrying food. such as “opposites” with examples of hydrolysis and condensation, or oxidation and reduction. They could group reactions with respect to the functional groups involved. 49. Answer can focus on such information as: plastics are made up of long chains so they are flexible so they can be molded into a variety of shapes but may also be hard and rigid and have uses where durability is important. They are used for many everyday products such as water bottles and plastic shopping bags, piping, conduit and their low density and high durability leads to many industrial and construction uses. 50. Refer to Appendix A page 712 SE format for Spider Organizer. The central concept should be the fact that both are polymers found in living systems. Other ideas from brainstorming would include: 28 MHR • Chemistry 12 Solutions Manual 978-0-07-106042-4 54. Answers can include: recycling of plastic bottles and other plastics in cafeteria; use of dishes rather than use plastics plates when possible; reuse plastic garbage bags; refrigerate left overs in reusable containers rather than covering with plastic wrap, use refillable bottle for water; …and more 55. Students should consult Appendix A, pages 712-14 if they are unsure of which organizer to choose. Alternatively, they could prepare a short audio report, animation, or other type of electronic presentation that covers the topics outlined on page 136 of the student textbook. 56. OH + n n HO 61. O CH3 CH3 Cl CH3 O Cl •R eact the 2-methylprop-1-ene-1,3-diol with HBr to produce 2-bromo-2-methylpropan-1,2-diol, as shown below. There will also be some 1-bromo2-methylpropan-1,2-diol which will have to be removed. • React carbonic acid with the 2-bromo-2methylpropan-1,2-diol to get the final product, also shown below. The second reaction is shown with the compounds shaped so it is clear that the two OH groups on the carbonic acid will react with the two alcohol groups on the 2-bromo-2-methylpropan-1,2diol. 2n HCl O O CH3 n BPA mimics human hormones and can have negative neurological effects especially if ingested at a young age. BPA is useful because it makes Polycarbonate plastic, which is clear and nearly shatter-proof. 57. Note: Assume that the starting material is bromomethane and the product is methyl octanoate. HO CH C Convert bromomethane to methanol through a substitution reaction. Oxidize octan-1-ol to an aldehyde then to the carboxylic acid, octanoic acid. Esterification reaction between methanol and octanoic acid will produce methyl octanoate C O HO CH3OH + C7H15COOH → HO H2O + CH3-O–CO−C7H15 •C arry out an elimination reaction by treating bromoethane with NaOCH2CH3 to produce ethene. • Carry out a reduction reaction on propan-2-one to produce propan-2-ol. • Carry out an elimination reaction by treating propan-2-ol with with sulfuric acid to produce propene. • Carry out an addition polymerization with the ethene and propene. 60. a. As the particles become small enough, animals including fish and birds can ingest the plastic. This cannot be digested and can interfere with normal functions in their bodies. Death can result from this or from blockage of airways. Also, further degradation can release harmful chemicals. b. Reduce, Reuse, Recycle. CH2 CH2 OH Br C7H15CH=O + [O] → C7H15COOH 59. → CH3 HO C8H17OH + [O] → C7H15CH=O → + [O] → C7H15COOH 58. There is cross linking between strands specifically the formation of hydrogen bonds between N−H and O=C As well there is strength from the aromatic stacking interactions. OH + HBr CH3 CH3−Br + OH− → CH3OH + Br− CH2 C OH + CH2 CH3 O OH C → 2H2O + CH2 O C + CH2 CH3 C O CH2 Br Br 62. You can use the alcohol of the carboxylic acid you need with the same R group and then oxidize it with an oxidizing agent. You could also find an alkene with a C1–C2 double bond and perform an addition reaction to make it into an alcohol which you can then oxidize 63. For example: alanine phenylalanine O H N CH H CH3 C serine O N CH H CH2 C O N CH H CH2 C OH OH 64. • O xidize the original oct-6-ene-1-ol to oct-6-eneoic acid • Carry out an addition reaction with water to convert the oct-6-eneoicacid to 6-hydroxyoctanoic acid. Unit 1 Part A • MHR 29 • Carry out a condensation polymerization reaction to product the poly-6-hydroxyoctanoic acid. OH O + [O] → OH O + H2O OH OH O n 12. a. 2-methylpropan-2-yl 2,2-dimethylbutanoate + water, b. N-propyl-3-chlorobutanamide + water O OH 13. cycloheptene + H2O → cycloheptanol + [O] → cycloheptanone OH → nH2O + 14. a. addition polymer CH2=CH—C≡N b. condensation polymer OH O ... 11. Amino acids would be found in muscle-building supplements because they are the monomers of proteins which help athletes build muscle. (In reality, only exercise can build muscle.) O O O O O ... 65. Use different coloured paper clips. For example nylon 6,6. The monomers are adipyl chloride and hexamethylene diamine can be represented by different colours or sizes of paper clips. 66. a. H H H H H H H H H C C C C C C C C H H H H H H H H H b. 2C8H18(ℓ) + 25O2(g) → 16CO2(g) + 18H2O(ℓ) c. CO2, a major greenhouse gas that is linked to global warming and acid precipitation, is constantly added to the environment. Combustion is usually incomplete, thus adding soot and carbon monoxide to the atmosphere. Also, the octane has additives that can further pollute the air. Answers to Chapter 2 Self-Assessment Questions (Student textbook pages 142-3) 1. d 2. c 3. b 4. d 5. a 6. e 7. b 8. d 9. b 10. c 30 MHR • Chemistry 12 Solutions Manual 978-0-07-106042-4 O HO O OH HO HO 15. Both cellulose and starch are polymers with glucose as the monomer. However they differ in how the glucose monomers are linked together. Cellulose has beta linkages and starch has alpha linkages. Because of the beta linkages humans cannot digest cellulose; we do not have the enzymes that recognize beta linkages. Cellulose fibers are used to compose wood, paper, cotton and flax. Starch is used as an energy storage unit for plants. 16. • reduce the carboxylic acid to an aldehyde •reduce the aldehyde to an alcohol • an elimination reaction of the alcohol to make an alkene • add the alkene to itself to perform an addition polymerization reaction 17. a. 2-chloroheptane and 3-chloroheptane; In the reactant, the two carbon atoms involved in the double bond are bonded to an equal number of H atoms and an equal number of C atoms. Therefore, neither product will be preferred. b. 2-methylhept-3-ene and 6-methylhept-3-ene Carbon atoms 3 and 5 are bonded to the same number of other carbon atoms as well as the same number of hydrogen atoms. Therefore, neither product is preferred. 18. Essay can focus on common uses such as furniture, cooking utensils, car parts, fabrics, toys, footwear, bags, phones, or computers. If we depended on natural materials for these uses, many applications would not be possible. Also there would not be enough natural products to make items to support the world population. 19. (CH3)2 CHCH=CHCH3 + 9O2 → 6CO2 + 6H2O 20. Polyamide. The −COOH of one amino acid reacts with NH2 of another amino acid to form amide linkages. 21. The number of C−O bonds decrease or the number of C−H bonds increase 22. a. CH3CH2C(Cl)=CH(Cl) and CH3CH2C(Cl)2–CH(Cl)2, b. cyclopentene + water c. HO-CH2CH2CH3 + Cl23. butanone + [H] → butan-2-ol butan-2-ol + HCl → 2-chlorobutane + water 24. a. hexyl propanoate + water, b. cyclobutanol 25. HOOC−CH2−CH2−CH2−CH2−OH with H2SO4 as a catalyst The −OH group on one end of the molecule will react with the −COOH group on the other end to form the cyclic compound. Answers to Unit 1 Review Questions (Student textbook pages 147-53) 1. c 2. c 3. b 4. b 5. a 6. d 7. b 8. c 9. b 10. e 11. a 12. e 13. a 14. c 15. a. alkene b. alkane c. alkene or cycloalkane d. alkyne 16 a. These are not constitutional (structural) isomers but the same molecule rotated 180 degrees. b. These are constitutional (structural) isomers, as the longest chain containing the double bond is five carbons long, whereas the second has the longest chain containing the double bond is only four carbons long. 17. Both types of stereoisomers have their atoms bonded in the same sequence on the carbon chain. Cis/trans (Z/E) diastereomers (geometric isomers) have two unique atoms or groups arranged on the same side (cis/Z) or on opposite sides (trans/E) of the double bonds. They have different physical but similar chemical properties. Enantiomers (optical isomers) are non-superimposable mirror images of each other and don’t require a double bond. They have essentially the same physical and chemical properties except how the rotate plane-polarized light and react with other enantiomers and with enzymes. 18 a. substitution b. addition c. condensation d. hydrolysis e. elimination f. combustion 19. A polymer is a long-chained molecule made up of repeating units. A monomer is the unit which repeats in a polymer. Glucose is a monomer and starch is one of its polymers. 20. Primary amides would be expected to be more soluble in water as they have the greatest number of N–H bonds that allows for hydrogen bonding with H2O. 21. They are both made through condensation polymerization reactions. Polyamides contain amide linkages, –CO–NH– while polyesters contain ester linkages, –CO–O–. 22. The reactant in an addition reaction is an alkene which must contain a double bond between two carbon atoms. When a small molecule such as HX is added to an asymmetric alkene, two products can form because the X could be added to either of the carbon atoms involved in the double bond. Markovnikov’s rule is used to predict which product is more abundant. Also, two different products can form when each double bond has two different atoms or groups of atoms single bonded to it. The products will be cis and trans isomers. 23. Petrochemicals are products derived from petroleum. Basic hydrocarbons, such as ethene and propene, are converted into plastics and other synthetic materials. 24. a. chloroprene, b. methyl methacrylate Unit 1 Part A • MHR 31 low solubility in water. Propan-1-ol would both be soluble in water because both can enter into hydrogen bonding. The –COOH group in propanoic acid makes this molecule more polar than the corresponding alcohol and it will have the higher boiling point will be higher than the alcohol. Propanoic acid will turn litmus red. 25. condensation polymerization 26. a. addition b. condensation c. combustion 27. a. oxidation b. reduction 28. a. hydrolysis b. esterification and condensation 33. Esterification (cyclic) and polymerization O 29. a. N-butylethanamide b. cyclopentylbutanoate 30. a. The longest carbon chain is five carbon atoms long. The correct name is pentane. b. Numbering of the side groups should give the lowest places on the longest chain for alkanes. The correct name would be 2,3-dimethylpentane. c. Side groups on an alkane should be placed in alphabetic order excluding multiplying prefixes. The correct name would be 3-ethyl-2,2-dimethylnonane. d. The benzene group has the greatest number of carbon atoms and therefore would receive the root name. The correct name would be 1-pentylbenzene. 31. a. Aldehydes are always at the end of a carbon chain. The molecule would be a ketone and have the name propanone. b. Numbering of a cycloalkane would place the halogens in alphabetic order giving the first in the alphabet the lowest number. The correct name would be 1-bromo-2-chlorocyclobutane. c. The alcohol group would receive the lowest number in the longest chain. The longest carbon chain that does not contain multiple bonds is nine carbons long. The correct name would be 7-methylnonan-3ol. d. The longest carbon chain in an ether gets the root name. The correct name would be ethoxybutane. e. The longest unsaturated chain receives the root name. Numbering gives the multiple bond the lowest number. The correct name is 2-ethylpent-1ene. f. The longest carbon chain in the root name is five carbons long. The correct name would be methyl-3methylpentanoate 32. Use difference in their boiling points, solubility in water and reaction to litmus to distinguish between these molecules. Propyne would have the weakest intermolecular forces (dispersion forces) between molecules and therefore the lowest boiling point and be a gas at room temperature. The gas would have a 32 MHR • Chemistry 12 Solutions Manual 978-0-07-106042-4 O H2SO4 OH HO C CH2 CH2 CH2 CH2 O n O H2SO4 OH HO + H2O CH2 n H2O + O ... O C CH2 CH2 CH2 CH2 CH2 O O C CH2 CH2 CH2 CH2 CH2 ... 34. Convert ethane to ethene by cracking. CH3—CH3 800PtºC CH2=CH2 + H2 Convert ethene into ethanol by addition of H2O. CH2=CH2 + H2O → CH3—CH2OH Convert ethanol to ethoxy ethane by dehydration. This reaction requires strong sulfuric acid as a catalyst and high temperatures. H SO 2CH3—CH2OH heat CH3—CH2—O—CH2—CH3 + H2O 35. a. propan-1-ol + ethanol b. 3-chloro-2,2-dimethylpentane c. N-methyl-N-(2-methylpropyl)ethanamide • • • 2 4 36. a. A is ethane; C is ethanol; B is ethyl ethanoate ; D is ethanoic acid b. ethane CH3—CH3; ethanol CH3—CH2—OH; ethyl ethanoate CH3—CH2—CO—O—CH2—CH3; ethanoic acid CH3— COOH 37. a. Both molecules have aromatic (benzene) rings and halogens. b. Both names contain the name phenyl which is benzene ring, the prefix bi- which indicates that there are two benzene rings, and the name of a halogen. c. The molecules would be expected to be liquids or solids due to the large number of carbon atoms and highly electronegative halogen atoms there would be significant dispersion forces between molecules. d. These molecules would not be soluble in water but be soluble in non-polar substances such as hydrocarbons (oils & fats for example). e. They would be expected to have other similar physical properties such as melting point boiling point density. They may have similar physiological effects since they can dissolve and accumulate in fat tissue 38. an ether 39. Carry out a substitution reaction of benzene with bromine. benzene + 2Br2 →1,3-dibromobenzene + HBr 40. a. 7-methylocta-2,6-dien-1-ol b. It would be a volatile liquid at room temperature. It would be slightly soluble in polar solvents and very soluble in non-polar solvents. c. Ethanol would be a suitable solvent as it would evaporate quickly allowing the geraniol to slowly volatilize. 41 a. Amino acids have both amino, –NH2, and carboxyl, –COOH, functional groups. b. Glycine would be named 2-aminoethanoic acid and alanine would be 2-amino-propanoic acid. c. Glycine would be more soluble in water than alanine as it has fewer alkyl groups. 42. a. O b. It should be a gas at room temperature, be soluble in non-polar solvents and of low solubility in water. c. Its extreme flammability would be one of the reasons for not being used in operating rooms. 43. • monomer CH3—CH=CH—CH3 • polybutene –[—CH(CH3)—CH(CH3)—]n – • solvent alkylethers, tertiary alcohols • acid catalyst WHMIS: 2-butene is a gas at room temperature, highly flammable, explosive with air mixture, inhalation can cause dizziness and unconsciousness, evaporation from skin can lead to frostbite, use face shield 44. a. butanal, butanoic acid b. 4-methylhexan-3-ol 45. a. poly-1,1-dichloroethene; ... CH2 CCl2 CH2 CCl2 CCl2 CH2 CH2 ... CCl2 b. trade name is Dacron ... O O O C C O CH2 CH2 O O O C C O CH2 CH2 ... 46. a. • use 2 fats and 2 oils • a dd equal portions of each fat and oil to separate test tubes • a dded a measured volume of bromine water to each test tube • s hake gently or warm in a water bath while looking for a decrease in the intensity of the reddish colour of bromine water. b. Br2(aq) WHMIS: Corrosive. Harmful if inhaled. Causes respiratory tract irritation and possible burns. Causes eye and skin irritation and possible burns. Wear gloves when making the bromine water. Work in a fume hood. c. addition d. H3C—CH(Br)—CH(Br)—CH3 47. Ethanol is the only one of the three that will mix with water. Adding water to each will indicate which one is ethanol. Hex-2-ene can be separated from benzene by the addition of Br2(aq). The bromine water will discolour as it reacts with the hex-2-ene but will not react with benzene. 48. a. 3-hydroxypropanoic acid b. 4-aminobutanal 49. butane; 3-methylpentane; 2-chloropentane; 2-iodopentane; 1-bromohexane 50. • Oxidize the ethanol all the way to ethanoic acid. • Carry out an addition reaction using HCl with the non-1-en-5-amine to form 2-chloronon-5-amine. • Carry out a condensation reaction between the ethanoic acid with the 2-chloronon-5-amine in the presence of an acid catalyst to form the amide bond. 51. The teacher might suggest to the students that they start this question early and carry a list of the classes of compounds for several days or a week. As they are in different locations, they can look for examples. It would be interesting for them to look for a certain category of used (e.g. foods, medications, cleaning solutions) that a particular hydrocarbon or derivative fits into. Unit 1 Part A • MHR 33 ‑52. 58. Students have 58 terms to consider and link; organization will most likely reflect the section organization of the two chapters. Answers should include additional explanatory words to show meaningful relationships between the words and clusters of words. H C H Cl H The chlorine atom is above the plane of the paper, one hydrogen atom is below and two hydrogen atoms are in the plane of the paper. 59. Some ideas to expand on: The disposal of items and products made of plastic leads to very large amounts of waste that is harmful to the environment. Since they take a very long time to degrade, they take up space in land disposal sites. No one wants garbage sites near where they live so there are not many places to put this waste. There is a large mass of garbage in the ocean which is mostly made up of plastics. This interferes with marine life and can cause the death of animal life in the ocean. Reuse and recycling are part of the solution to this problem. 53. The simplest hydrocarbon that can form cis and trans isomers is 2-butene. H H HH 3C C C HCH3 C C cis-2-butene CH3 H3C Cl 54. Br Cl C F Br CCH3F CH3 CH3 H C H3H C H3C C H3 CH C -2-butene C trans H Cl F ClC F Br 60. All aspects of our everyday life have uses of organic compounds. The answer should cover a wide variety of uses and abuses of e.g. pharmaceuticals, plastics, food additives, fuels. CCH3Br CH3 The diagrams show that 1-bromo-1-chloro-1fluoroethane can form non-superimposable mirror images of each other. Therefore, there can be enantiomers of 1-bromo-1-chloro-1-fluoroethane. 55. Sample answer: Cotton requires large amounts of water to grow and a large amount of pesticides are used on the plant. Polyester uses 10 times more energy than cotton during production and produces 4 times more carbon dioxide 61. One possible flowchart is: Organic compounds Addition Elimination Substitution Esterification 56. • complete combustion – excess of O2(g) available; products of complete combustion of hydrocarbons are only carbon dioxide and water. • complete and incomplete combustion - starting material is a hydrocarbon; CO2 and H2O are always produced • incomplete combustion – insufficient O2(g) available; less heat given off; in addition to CO2 and H2O, CO and C are also products. Incomplete combustion is dangerous because CO is poisonous, colourless, odourless, gas that is undetectable to our senses. 57. Life in the 1800s would centre around providing necessities rather than conveniences. Discuss availability of choices in modes of travel, clothing, furniture, type of work. 34 MHR • Chemistry 12 Solutions Manual 978-0-07-106042-4 Functional groups Reactions between organic compounds and the resulting products are controlled by the types of functional groups present. Reactions of organic compounds Synthetic polymers Petrochemicals Organic compounds are defined by the funtional group(s) that they contain. Polymerization reactions(addition and condensation) produce very large molecules Natural polymers Biological molecules and their functions 62. One possible flowchart is illustrated below: Crude Oil Fractional distillation Cracking and reforming Ethene (ethylene) oxidation by addition of oxygen gas with a silver catalyst Ethylene oxide Xylene oxidation by addition of potassium permanganate Terephthalic acid Polymerization reactions (addition and condensation) produce very large molecules Ethylene glycol condensation polymerization Terephthalic acid 63. With respect to solubility, the statement is too general to agree with. The general statement that matches this is that “like dissolves like” Non-polar solvents dissolve non-polar compounds and polar solvents dissolve polar compounds. Water is a polar solvent. Hydrocarbons are non-polar and have low solubility in water while organic compounds with a polar part on the molecule will dissolve in water. The ability to conduct an electric current depends on the presence of ions. Few organic compounds will form ions in solution; even carboxylic acids ionize only slightly. The statement is generally true regarding conductivity. 64. a. Formic acid is the simplest of the carboxylic acids, HCOOH. The IUPAC name is methanoic acid. b. Human use is to use formic acid as an antibacterial agent and preservative with animal feed; it can be reduced to formaldehyde, a preservative for animal specimens, it can act as a reducing agent to reduce metals from their solutions; it is used in the tanning industry; it is used to synthesize esters. c. Stinging insects such as bees and beetles will secrete formic acid. d. It is a defense mechanism to ward off predators. 65. a. Teflon has a very low coefficient of friction and the Teflon polymer is non-reactive to compounds found in foods. b. At high temperatures, above 240oC, it is known that Teflon breaks down and gives off toxic particles and gases. c. A safety note should be included cautioning users to not heat this pan above normal temperatures used for cooking. Do not place in an oven or on a barbeque. 66. a. Any molecule that has a large hydrocarbon chain with polar groups such as alcohols or carboxylic acids on the end would suffice. b. Emulsifiers make heterogeneous mixtures such with oil and water appear to be homogeneous. For example lecithin in egg yolks helps to prevent the separation of oil and vinegar mixtures in certain salad dressings. 67. Some examples would be pharmacist, medical doctor, researchers in the cosmetics, pesticides and polymer industries, food and drug analyst, petrochemical engineers, hazardous waste handlers as well as a myriad of others. Training for most of these programs would involve a four year undergraduate degree as well as possible post graduate degrees. To become a medical doctor would require at least six years. Only certain schools would offer pharmacy and medical programs 68. H3C CH2 CH2 CH2 O CH2 CH2 OH b. One would expect them to be considered flammable and possibly toxic in large doses. c. The sorbitan molecule contains alcohol, ether, ester and large alkyl functional groups. This combination would make one end of the molecule soluble in water and the other end soluble in the oil. d. Skimmers recapture the oil which could be reused but require much energy and effort. Burning removes it from the ecosystem but creates greenhouse gases and harms organisms on the surface. The dispersants reduce the concentration of the oil but just spread it and when used underwater may damage the ecosystem deeper than just on the surface. Other benefits and repercussions are possible. Unit 1 Part A • MHR 35 e. Reduce one’s use of fossil fuels such as using public transit, recycling plastics, encouraging governments companies to have safeguards in place are just some of the many answers students could give. 69. The chains of this polymer have –NH2 and –C=O groups attached, which allows hydrogen bonding to occur. This increases the strength. 70. The greater the intermolecular attractions between molecules the greater the boiling point. The boiling points of benzene and cyclohexane are higher than for hexane because the structure of these two compounds gives a greater surface area. This results in greater intermolecular attractions between their molecules. 71. (1) It is similar to a condensation reaction (2) reduction, (3) polymerization 72. The tar-like substance is most likely a long chain carbon compound that is non-polar. Vegetable oil would likely be the best since it has fairly long carbon chains and the esters that make it up are only slightly polar. 73. This is oxidation because a carbon atom in the product is bonded to fewer hydrogen atoms. 77. a. With so many organic compounds widely used, solvents have become specific for various classes of compounds. The advantage is that there are no organic compounds for which a solvent cannot be found so that any compound can be cleaned of a surface. The disadvantage is that many organic solvents are volatile and are hazardous to our health if inhaled. Disposal of solvents is another problem since they can persist in the environment for long periods of time. b. Research should focus on absorption of solvents through the skin and inhalation. c. Results can be organized, for example, with respect type of health effect, seriousness of health effect, type of solvent d. Greater care could be taken to avoid using more of the solvent than necessary. Research the type of solvent that will dissolve a particular compound and use the one that has the least effect on health and the environment. Answers to Unit 1 Self-Assessment Questions (Student textbook pages 154-5) 1. b 74 a. Ethanol or grain alcohol, C2H5OH, is the alcohol present in wine, spirits and beer. b. Due to their ability to form hydrogen bonds, alcohols would be liquids or solids at room temperature. c. Due to the toxic and combustible nature one would expect the WHMIS symbols for poison and flammable to be on containers used in the workplace 2. e 75. Rusting is an oxidation of a metal. The oxidation and reduction discussed in this chapter have organic compounds as reactants. 9. b 76. Student answers will likely include some of the following points. The public often believes that “natural” is safer and better than “synthetic,” even if the compounds are identical. This is evident in natural and artificial flavourings, and with natural and artificial sweeteners. The public is prepared to pay a premium for “organic” or “natural” products, without knowing or understanding the differences between them. In order for consumers to make informed product choices, they have to thoroughly research the differences between the products. Many manufactured products have strict guidelines around labelling, while there are few if any guidelines around “natural” products. 36 MHR • Chemistry 12 Solutions Manual 978-0-07-106042-4 3. b 4. b 5. e 6. b 7. d 8. b 10. a 11. There are five structural isomers, one of which has two diasteroisomers. H H H H H C C C C H H cis or trans H H H H H H C C C C H 14. a. Vitamin C could form enantiomers as it has two carbon atoms that are bonded to four different atoms or groups. These two carbon atoms are circled in the figure below. H H H H H C C H H C C H H H HO HO HO H C H C C C H H 12. a. CH 2 H H C H C C C H H H CH H b. O CH2 CH2 CH3 CH3 c. O CH3 CH2 CH2 CH CH2 C OH CH2 CH2 CH3 e. CH3 alcohol to carboxylic acid: oxidation O C H C C H CH3 H O C C C H O H H CH2 CH2 H H H C C H C C 16. a. fuels b. beverages, antiseptics c. pharmaceuticals d. sour tasting foods such as vinegar e. artificial and natural flavourings These are just some examples of the many places students may find these substances haloalkane to alcohol: substitution H O H OH 17. alkane to haloalkane: substitution CH3 d. O 15 a. 3-ethyl-2,2-dimethyloctane b. 1-ethyl-2-fluorobenzene c. butan-2-ol d. 3-phenylnonane CH CH O b. Due to the large number of hydroxyl groups and oxygen atoms, which could hydrogen bond with other molecules, it would have a high melting point and be a solid at room temperature. Due to the large number of polar hydroxyl groups it would be soluble in water. c. Yes as fats are non-polar and vitamin C molecules polar, the vitamin C would not dissolve in the fats. It is water soluble and would be quickly eliminated from the body. H H H H H H H 13. Some benefits would be better medicines, dyes, foods, cosmetics, transportation, and agricultural yields. Some drawbacks would be increased reliance on hydrocarbons with the resulting environmental effects such as oil spills and emission of VOCs and ozone destroying CFCs. The release of toxins such as dioxins as well as drugs and pesticides that have had negative side effects on humans and the environment could also be mentioned CH2 CH2 CH3 Unit 1 Part A • MHR 37 C H 18. Molecules must have double bonds to undergo addition polymerization or they must have two functional groups which can react to combine and release a small molecule to undergo condensation polymerization. 19. The first polymer is an addition polymer and the second is a condensation polymer (polyamide). The polyamide would be stronger because its chains can hydrogen bond to each other. 20. Recycle bags, have a no plastic bag rule, buy degradable garbage bags. Have recycle containers available for soft drink and water bottles. 21. a. 3-methylpentan-2-ol + HCl b. 3-methylpentan-3-ol and H2SO4 as a catalyst 22. O O HO HO OH CH2 CH2 OH 38 MHR • Chemistry 12 Solutions Manual 978-0-07-106042-4 23. • Oxidize the ethanol first to ethanal and then to ethanoic acid. • Carry out an addition reaction to add water to the double bond of the but-3-en-2-amine producing 3-aminobutan-2-ol. • Combine the ethanoic acid and the 3-aminobutan2-ol and use sulfuric acid as a catalyst to carry out condensation reactions. The carboxyl group of one molecule of ethanoic acid will react with the amino group of the 3-aminobutan-2-ol, and the carboxyl group of a second molecule of ethanoic acid will react with the alcohol group on the other end of the 3-aminobutan-2-ol to form the desired compound. 24. a. major product: 3-bromo-3-methylpentane minor product: 2-bromo-3-methylpentane b. 3-methylbutanoic acid and ethanol c. 2-methylpentan-3-one 25. Small carbon chains ignite too early and explode instead of burn, causing incomplete combustion. This is also damaging to the engine. Carbon chains with more than 12 carbon atoms would not vaporize well enough and would therefore not undergo complete combustion. Soot would build up in the engine and cause damage.