Download getting started 3.1 hydrocarbons

GETTING STARTED
REFLECT ON YOUR LEARNING
(Page 178)
1. (Sample response) Organic compounds are similar in structure, similar in types of atoms, similar in size, and similar
in chemical reactivity.
2. Solubility: “like dissolves like;” compounds that have large nonpolar components tend to be soluble in nonpolar
solvents; and compounds that have small nonpolar components and polar groups such as C=O, OH, or NH groups
tend to be soluble in polar solvents
Melting and boiling points: compounds with strong intermolecular attractions tend to have higher melting and
boiling points because more energy is required to separate the molecules.
3. (Sample response) “Organic” means made by plants or animals; compounds that contain carbon atoms; grown
without use of synthetic materials.
TRY THIS ACTIVITY: KEEPING BABY DRY WITH POLYMERS
(Page 179)
(a) The addition of table salt causes some of the water to come out of the gel because the presence of sodium ions
reduces the attraction of water to the polymer, and thus reduces absorbency. The addition of sucrose or calcium
chloride does not produce any change because no sodium ions are added.
(b) Determine the mass of a dry diaper. Add a few millilitres of water to the absorbent surface of the diaper, then hold
the diaper vertically and note whether any leakage occurs. Repeat until the first sign of leakage of water occurs.
Determine the mass of the wet diaper. Subtract the mass of the dry diaper from the mass of the wet diaper to obtain
the mass of water absorbed. Calculate the volume of water absorbed, using the density of water (1.0 g/mL).
3.1 HYDROCARBONS
TRY THIS ACTIVITY: HYDROCARBONS ARE MADE OF…
(Page 180)
(a) The black powder formed is soot: pure carbon.
PRACTICE
(Page 183)
1. (a)
(b)
(c)
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(d)
2. (a) nonane, C9H20
(b) heptane, C7H16
PRACTICE
(Page 186)
3. (a)
(b)
(c)
(d)
(e)
(f)
4. (a) 1-pentene, C5H10
(b) 1-butyne, C4H6
(c) 2-heptene, C7H14
PRACTICE
(Page 188)
5. (a)
(b)
(c)
(d)
126
CH4 + 2 O2(g) → CO2(g) + 2 H2O(g)
2 CH3CH3 + 7 O2(g) → 4 CO2(g) + 6 H2O(g)
HC≡CCH3 + 4 O2(g) → 3 CO2(g) + 2 H2O(g)
CH3CH2CH=CHCH2CH3 + 9 O2(g) → 6 CO2(g) + 6 H2O(g)
Unit 3 Student Book Solutions
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TRY THIS ACTIVITY: TESTING FATS AND OILS
(Page 189)
(a) The samples that contained only saturated carbon chains (i.e., no unsaturated bonds) do not turn potassium
permanganate solution brown. All of these samples were oils (liquids at room temperature).
(b) Experimentally, the samples that turn potassium permanganate brown contain unsaturated carbon chains. Generally,
the fats (solids at room temperature) contain saturated carbon chains.
(c) The more solid the sample is at room temperature, the more likely it is that the sample contains saturated carbon
chains; the more liquid the sample is at room temperature, the more likely it is that the sample contains unsaturated
carbon chains.
PRACTICE
(Page 190)
6. (a)
(b)
(c)
(d)
7. 1-heptene, 2-heptene, and 3-heptene
SECTION 3.1 QUESTIONS
(Pages 190–191)
Understanding Concepts
1. (i) Carbon atoms can share electrons to form covalent bonds. (ii) Carbon atoms can form four bonds. (iii) Carbon
atoms can form covalent bonds with other carbon atoms. Therefore, they can join other carbon atoms to form
straight chains, branched chains, or ring structures.
Example: decane
2. (a) Alkenes contain one or more carbon−carbon double bonds.
(b) Alkynes contain one or more carbon−carbon triple bonds.
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3. Double and triple bonds are readily converted to single bonds. Thus, the presence of double or triple bonds in alkenes
and alkynes makes them more reactive than alkanes, which have only single bonds.
4. saturated hydrocarbon:
unsaturated hydrocarbon:
5. Since a single carbon atom cannot form a carbon−carbon double bond, no alkene with a single carbon exists. The
smallest alkene is therefore ethene, which contains two carbon atoms.
6.
7. There is no ambiguity in the location of the double bond: in ethene, the double bond can only be between the two
carbon atoms; and in propene, the double bond is between the middle carbon atom and one of the carbon atoms on
either side. In both cases, the structure is the same.
8. The correct name is 2-pentene because the carbon chain is numbered so that the lowest number indicates the location
of the double bond. The carbon chain of this molecule should be numbered in the opposite direction.
9. 2 C8H18 + 25 O2 → 16 CO2 + 18 H2O
10.
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11.
12. Student answers for the examples will vary.
Front:
Family name and
general formula
Examples
IUPAC name
Common name
Alkanes
CnHn+2
butane
lighter fluid
Alkenes
CnHn
propene
propylene
Alkynes
CnHn−2
ethyne
acetylene
Structural formula
Back:
Family
Characteristic properties
Characteristic
functional groups
Intermolecular forces
Alkanes
smaller molecules are gases at room
temperature, larger molecules tend to
be liquids or soft solids; soluble in
nonpolar solvents; generally unreactive
no functional groups; all
C−C bonds are
saturated
van der Waals forces
Alkenes
smaller molecules are gases at room
temperature, larger molecules tend to
be liquids or soft solids; soluble in
nonpolar solvents; undergo addition
reactions
C=C
van der Waals forces
Alkynes
smaller molecules are gases at room
temperature, larger molecules tend to
be liquids or soft solids; soluble in
nonpolar solvents; undergo addition
reactions
C≡C
van der Waals forces
Making Connections
13.
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Common name
Use
ethene
ethylene
reactant in the manufacture of
antifreeze
propene
propylene
raw material in making plastic
ethyne
acetylene
fuel for welding torches
Section 3.1 Student Book Solutions
129
14. Methane is a major component of natural gas, and is used as fuel in homes for cooking and heating, and in schools
for gas burners. Ethane is also a component of natural gas. Propane is a fuel used in gas barbecues. Butane is a fuel
used in cigarette lighters. Pentane and hexane are used in dry-cleaning solvents, naphtha gas, and camping fuel.
Pentane–decane are components of gasoline for cars. These alkanes are suitable for use as fuels because they all
combust readily and their combustion reactions are highly exothermic.
15. Global warming refers to an observed increase in average global temperatures. Some scientists suggest that this
effect is caused by the increase in concentrations of carbon dioxide in the atmosphere. Carbon dioxide gas seems to
trap infrared radiation emitted and reflected by Earth. The cause of the increase in carbon dioxide levels may be the
combustion of hydrocarbons, producing carbon dioxide and water.
16. When the lighter is “flicked,” the spark wheel rubs against the piece of flint, creating a spark. The spark ignites the
butane gas coming out of the gas tank through the flame nozzle. The lighter cap must be open to have a flame. If the
cap is closed, the flame is extinguished.
Extension
17. Student answers may vary. Hydrocarbons may form ring structures of several carbon atoms, some with double
bonds. Two examples are 1,3-dimethylcyclopentane
and methylbenzene (more commonly called toluene), in which a methyl group is attached to a six-carbon ring
structure with a unique arrangement of double bonds.
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3.2 ACTIVITY: BUILDING MOLECULAR MODELS
(Page 192)
Observations
Sample Observation Table
Procedural step
Name
Formula
2.
butane
C4H10
3.
1-butene
C4H8
Structural formula
2-butene
4.
1-butyne
C4H6
2-butyne
1,2-butadiene
1,3-butadiene
[Students are not expected to be able to name the alkenes with two double bonds because this nomenclature was not
taught in the section.]
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Section 3.2 Student Book Solutions
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Synthesis
(c) (i) one (ii) three (iii) three
(d) (i) There is no functional group for which we need to indicate a location.
(ii) The carbon chain should be numbered in the opposite direction to give the lowest number: 2-hexene.
(iii) There can be no triple bond formed by a single carbon atom.
(e) A wooden stick is used to form the first bond in a multiple bond; the second or third bonds are formed by a spring,
which more readily comes undone.
Extension
(f)
Isomer: 1-hexene
3.3 FRACTIONAL DISTILLATION AND CRACKING
TRY THIS ACTIVITY: THE GREAT MARBLE RACE
(Page 193)
(a) The marbles travelled more slowly in the oils designed for summer, and more quickly in the oils designed for winter.
We could conclude that the “summer” oils are thicker (more viscous) than the “winter” oils. When each oil was
cooled in the ice bath, the marbles travelled more slowly in them than before cooling. Similarly, the marbles
travelled more quickly in the warmed oils. Cooler oils appear to be more viscous than warmer oils.
An explanation for these observations is that the forces of attraction between the molecules in the summer oils
were stronger than the forces of attraction between molecules in the winter oils. Also, when cooled, the molecules
moved more slowly and were closer together, with stronger forces of attraction. The reverse is true for the warmed
oils.
(b) In cold winter temperatures, motor oils become more viscous. Therefore, a less viscous oil is needed in winter in
order to have the same viscosity as the summer oils.
SECTION 3.3 QUESTIONS
(Page 196)
Understanding Concepts
1. Petroleum is a complex mixture of hydrocarbon molecules, formed from prehistoric plants and animals. This mixture
contains gases, liquids, and dissolved solids composed of many different hydrocarbon molecules, some of which
may be up to 40 carbon atoms long. Some components are used as fuels for heat and cooking, dry-cleaning solvents,
gasoline, kerosene and diesel fuel, furnace oil, heavy greases, waxes, cosmetics, polishes, and asphalt and tar for
roofs and roads.
2. (a) The small hydrocarbons molecules, such as methane, ethane, propane, and butane, exist as gases. Larger
hydrocarbons are liquids, and the largest molecules, with boiling points over 400°C, exist as solids. The smaller
the molecule is, the lower the boiling point it has.
(b) In fractional distillation, the entire mixture of hydrocarbons is first heated to very high temperatureshigh
enough to evaporate nearly all of the hydrocarbons, small and large. Then, the hot gases are allowed to rise
in a tall fractionation tower. The upper parts of the tower are cooler than the lower parts. Each gas condenses
at its own boiling point. As the hot gases travel up through the lower, warmer sections, the larger molecules
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3.
4.
5.
6.
condense. As the gases ascend higher, the smaller molecules also condense. As each fraction condenses, the
liquid formed is collected on trays.
This fraction boils at 10°C; that is, it is a liquid below 10°C because it has not yet boiled, and is a gas above 10°C
because it has already boiled. Therefore, it is a gas at 20°C.
Cracking is the process used to convert large straight-chain hydrocarbons into smaller branched-chain hydrocarbons,
usually by heating with a catalyst. This process is important because one of the most valuable and profitable
petroleum products is high-octane gasoline, which contains highly branched alkanes.
The approximate boiling point of propane is under 30°C, while waxes boil at over 450°C. The difference is due to
intermolecular forces. As the length of the hydrocarbon molecules increases, the strength of the van der Waals forces
between molecules increases as well, so more heat is required to pull the molecules apart. Therefore, higher
temperatures are required to pull the molecules far enough apart to change the substance to a gas.
Student answer will vary.
(a) propane in a gas barbecue; butane in a lighter
(b) kerosene in a camping stove or lamp; lubricating oil for a bicycle chain
(c) wax in candles; asphalt on roads
Applying Inquiry Skills
7.
The mixture can be separated by distillation, using the apparatus shown. The distillation column allows the
evaporated gases to rise; the thermometer reads the temperature of the gases; the condenser, cooled by cold water,
condenses the evaporated gases. The mixture is placed in the round-bottom flask and heated gently. The hydrocarbon
with the lower boiling point will evaporate first, condense, and be collected. The temperature of the column will then
rise until the boiling point of the other hydrocarbon is reached. At that point, the hydrocarbon with the higher boiling
point will evaporate and be collected.
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Section 3.3 Student Book Solutions
133
Making Connections
8. Canada exports approximately 60% of its crude oilmainly heavy crude oil from western Canada to the United
States. Canada also imports light crude oil from the United States by pipeline, or from abroad by tankers. Canada’s
northern territoriesYukon, Northwest Territories, and Nunavuthave large resources of crude oil. Exploration for
crude oil also began in Atlantic Canada about 50 years ago, in Nova Scotia, Newfoundland, New Brunswick, and
Prince Edward Island. Alberta remains the focus of the petroleum industry in Canada, producing 70% of the
country’s crude oil. Crude oil is fractionated, and the collected components are used for fuel such as gasoline, jet
fuel, kerosene, diesel oil, and for other purposes, such as lubricating oils, waxes, and asphalt.
9. Motor oils may contain viscosity improvers, anti-wear additives, anti-oxidants, anti-foam agents, and detergents to
maintain engine cleanliness. 5W30 and 10W30 are the most commonly used motor oils. They are thin enough for
cranking at low temperatures, and thick enough to lubricate satisfactorily at high temperatures. In warmer seasons,
use more viscous motor oils (higher numbers). In colder seasons, use less viscous motor oils (lower numbers). The
following motor oils are recommended for the lowest expected temperatures listed:
Lowest expected
temperature
Type of motor oil
Brand
Cost
0°C
5W20, 5W30, 10W30,
10W40, 20W50
Under $4/L
–18°C
5W20, 5W30, 10W30,
10W40
Under $4/L
Below –18°C
5W20, 5W30
Under $4/L
10. In Canada, fossil fuels provide over 85% of our total energy use. These fuels, which include coal, crude oil, and
natural gas, are formed over millions of years from long-dead plant and animal material. That is why they are called
fossil fuels. There is a concern about their use because they are non-renewable: when we have exhausted the existing
supply, there will be no more fossil fuels available. Another concern about the use of fossil fuels is that, when
burned, these hydrocarbons produce carbon dioxidea product that may be partly responsible for global warming.
11. Student answers will vary. Possible answers include: home heating (service technician, furnace maintenance, air
conditioning installation); furniture stripping and refinishing (repairs and restoration); hobby shopsplastic model
cars and airplanes (salesperson); painting service (home painting and renovations); hot tubs and spas (service
technician and installer); insulation contractors (installers and maintenance technicians); lamination products and
services (service personnel); lawn maintenance (fertilizer application); automotive industry (oil changes and
lubrication services); packaging services (materials supplier); plastic patio furniture supplier (retail staff); driveway
sealing (asphalt sealing); photo finishing (film developing); pipe fabricating (factory staff); plastics (moulders);
plumbing contractors (installers); recording services (sound and video technicians); refrigerators and freezers
(technicians)
3.4 INVESTIGATION: SEPARATING A MIXTURE BY DISTILLATION
(Pages 197–198)
Prediction
(a) Substances with the lowest boiling point will be recovered first. Components will be recovered in the following order
(from first to last): hexane, 2-methyl-2-propanol, and paraffin wax. The reasons for this order are that propanol
contains an –OH group, which causes hydrogen bonding between molecules. Hydrogen bonds are stronger
intermolecular forces than the van der Waals forces that exist between hexane molecules. Paraffin wax consists of
much longer molecules than either hexane or propanol, and thus has stronger van der Waals forces than the other two
hydrocarbons.
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(b) Boiling points:
hexane: 67.8°C
2-methyl-2-propanol: 82°C
paraffin wax: 169°C
Analysis
(c) to (e)
The temperature remains at the boiling point of the first fraction until it has completely boiled off (arrow 1); then the
temperature rises again.
Bracket 2, over the second plateau, indicates the time over which the 2-methyl-2-propanol was boiling off and being
collected. During this time, the temperature of the mixture remained constant.
(f) The boiling points are the temperature readings at the first and second plateaus: 68°C and 82°C.
Evaluation
(g) There may be a lag in time from the temperature readings graphed and the fractions collected in the flask because it
may take time for the vapour to condense and to travel down the condenser. The graph may not show clear plateaus
because the difference in boiling points may not be sufficient for a sharp separation. Suggested improvements
include gentler, more even heating, and using a longer distillation column.
(h) Student answer may vary. Discrepancies may be due to impurities in the mixture, heating too rapidly, and suboptimal apparatus (e.g., insufficient length of column).
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3.5 FUNCTIONAL GROUPS
TRY THIS ACTIVITY: BENDING WATER
(Page 200)
(a) hexaneno functional groups
alcoholhydroxyl group, –OH
diethyl etheran oxygen atom bonded to two alkyl groups
acetonea carbonyl group, C=O
(b) A stream of hexane does not bend because it has no polar groups that are attracted to (or repelled by) a charged
object. The stream of alcohol bends because the –OH group is polar and is strongly attracted to (or repelled by) the
charged object. The stream of diethyl ether does not bend, or only very slightly, because the oxygen atom bonded to
two alkyl groups is only slightly polar, and thus is only slightly affected, if at all, by a charged object. The carbonyl
group in acetone is a polar group and thus causes the acetone molecules to be attracted to (or repelled by) the charged
object, so the stream of liquid bends.
SECTION 3.5 QUESTIONS
(Page 201)
Understanding Concepts
1. A functional group is a structural arrangement of atoms that, because of their electronegativity and bonding type,
imparts particular characteristics to the molecule.
2. C=C and C)C bonds are more reactive than C–C bonds because the second and third bonds formed are weaker than
the single bonds formed, and are thus more easily broken, making the multiple bonds more reactive.
3. In general, polar molecules have higher boiling points than less polar molecules because polar molecules have
stronger intermolecular attractions that require more energy (higher temperatures) to overcome. Very large nonpolar
molecules are affected by London dispersion forces that may cause their boiling points to be comparable to those of
smaller polar molecules.
4. Functional groups can contain carbon–carbon multiple bonds, which are more reactive than single C–C bonds; single
bonds between carbon and more electronegative atoms (e.g., O, N, or a halogen atom), which result in polar bonds
and hydrogen bonding; and carbon double-bonded to oxygen, a highly polar bond.
5. (a) The –OH or –NH functional group raises the melting and boiling points of a compound because the increased
polarity of the molecule increases intermolecular forces of attraction, requiring more energy to separate the
molecules.
(b) The functional group increases the solubility in polar solvents because –OH and –NH groups allow increased
hydrogen bonding with polar solvents.
6. (a) –OH group; high solubility in water
(b) carbon–carbon double bond; low solubility in water
(c) carbonyl group, C=O; high solubility in water
(d) –OH group and carbonyl group, C=O; high solubility in water
7. (a) H2O, NH3, CH4
(b) Water and ammonia are mutually soluble, but methane is not soluble in the other two compounds. The
electronegativities of O, N, C, and H are 3.5, 3.0, 2.5, and 2.1, respectively. Thus, the O–H and N–H bonds in
water and in ammonia are more polar than the C–H bonds in methane. The polar bonds in water and ammonia
allow them to form hydrogen bonds. Thus, they are soluble in each other.
(c) All three compounds may be considered organic because they are produced by living organisms (e.g., water by
animals and plants, ammonia and methane by bacteria). According to the chemical definition of “organic,” that
is, containing carbon, only methane is organic.
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3.6 EXPLORE AN ISSUE: THE COST OF YOUR COLD DRINK
Understanding the Issue
(Page 203)
1.
2.
3.
4.
5.
A coolant repeatedly evaporates and condenses in the cooling coils. The coolant absorbs heat when it evaporates.
This heat is extracted from the foods and drinks in the fridge, thus cooling them.
Ammonia, methyl chloride, and sulfur dioxide were used in the later 1800s. These substances are toxic. Freon was
used in the 1920s. It is nontoxic and unreactive, but causes damage to the ozone layer in the upper atmosphere. Since
the 1970s, HCFCs and HFCs have been used. Switching to these compounds may reduce environmental damage.
Propane (C3H8), butane (C4H10); since they do not contain halogens, they do not affect the ozone layer.
North American consumers prefer larger refrigerators and additional features, such as automatic defrost, that require
much larger quantities of coolant. North American manufacturers are also reluctant to abandon older technology in
which they have invested time and money.
[Sample answer] Consumers can influence manufacturers’ decisions by writing to manufacturers, offering concerns
and suggestions; organizing information sessions and inviting representatives from manufacturers; writing letters to
newspapers; contacting politicians, such as government environmental agencies; informing retail outlets of their
preference; and not buying products that do not meet consumers’ expectations.
Role Play: Choosing a Refrigerant
(Page 203)
(a) [Sample answer] One other way of measuring cost is the political cost. Local politicians have to think about what is
best for their constituents, and what will help them get re-elected. Union reps must consider the political cost, for
their union, of supporting one type of coolant over another. If choosing one type of coolant results in fewer fridges
being sold, and therefore fewer being ordered and manufactured, the union members might be unhappy with the
union reps who chose this course of action, and withdraw their support. If union reps support the most
environmentally friendly option, union members might applaud their ethical stand, and support them politically.
(b) [Sample answer] As the local MP, I would be very anxious to bring well-paying jobs to my community. I would
probably back the technology that would result in the most jobs, and ensure some stability for those jobs. If we could
get a Greenfreeze research lab built in the area, as well as the manufacturing facility, we would have even more jobs.
I would win support for helping to preserve the ozone layer. However, I would have to be confident that the
Greenfreeze refrigerators would sell well, otherwise my constituents would be laid off from the factory. My
popularity would decline and I might lose me my seat in office.
(d) [Sample answer] Points in favour of HFCs and HCFCs: proven technology, minimal changes for manufacturers to
production lines, an improvement on the old CFCs, refrigerators are likely to be cheaper and to sell well, HFCs and
HCFCs are nontoxic and inert, unlike the butane in Greenfreeze.
Points in favour of Greenfreeze: even more ozone-friendly than HFCs and HCFCs, long-term health could improve,
the technology already exists in Europe, North Americans would have environmentally friendly options when
choosing a refrigerator, the publicity of introducing a new technology would help sales.
3.7 ALCOHOLS AND ETHERS
PRACTICE
(Page 206)
1. (a)
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Section 3.7 Student Book Solutions
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(b)
(c)
(d)
2. (a) 3-pentanol
(b) 3-heptanol
TRY THIS ACTIVITY: BURNING PAPER
(Page 207)
(a) The paper remains unchanged, possibly because any heat generated by the burning alcohol is absorbed by the water
and the alcohol as it evaporates. The paper never becomes hot enough to burn. The alcohol burns off, leaving only
water, which extinguishes the flame.
CAREER CONNECTON: PHARMACY TECHNICIAN
(Page 207)
(i) Job description: responsible for preparing and packaging medications; maintains dispensing records for medications,
supplies, and equipment; inspects medical areas; maintains storage standards.
Qualifications: secondary school diploma; strong science background; good math skills; knowledge of pharmacy
terminology, medication names, and aseptic techniques; pharmacy technician program certification.
Salary: below-average hourly wage of about $13.67 (compared to national average of $16.91).
(ii) [Sample answer]
Human Resources Department
North-Western Hospital
Pine Valley, Ontario
Dear Sir/Madam:
I am writing in response to your advertisement for a Pharmacy Technician, posted in the Pine Valley Examiner on
Saturday, 29 February. I am very interested in that position. I have recently graduated with excellent marks from
Mohawk College’s two-year Pharmacy Technician Program. I also have good “people skills,” and enjoy working in
a team.
My resume is attached, with all my contact information.
I look forward to hearing from you to arrange an interview.
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SECTION 3.7 QUESTIONS
(Page 208)
Understanding Concepts
1. The presence of a hydroxyl group in methanol makes the molecule more polar than methane, and allows hydrogen
bonding between molecules. Hydrogen bonding results in a higher boiling point for methanol.
2. (a)
(b)
3. In 4-hexanol, the –OH group is on carbon atom 4, on a six-carbon backbone. The carbon chain should be numbered
in the opposite direction to give the lowest possible number for the functional group. The correct name is 3-hexanol.
4. butane, 1-butanol, octane, 1-octanol (lowest to highest boiling point)
5. (a) C2H5OH + 3 O2 → 2 CO2 + 3 H2O
(b) 2 CH3CH(OH)CH3 + 9 O2 → 6 CO2 + 8 H2O
6. (a) Ethoxypropane will evaporate at a lower temperature because, unlike 1-pentanol, it does not have a polar –OH
group.
(b) Ethoxypropane has a higher solubility in a nonpolar solvent because it is less polar than 1-pentanol.
7. Student answers for the examples will vary.
Front:
Family name
and general
formula
Examples
IUPAC name
Common name
Alcohols
R−OH
2-butanol
none
Ethers
R−O−R
ethoxypropane
none
Structural formula
Back:
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Family
Characteristic properties
Characteristic
functional groups
Intermolecular forces
Alcohols
soluble in water and some nonpolar
solvents; react with carboxylic acids to
form esters
hydroxyl group
hydrogen bonds, van
der Waals forces
Ethers
soluble in nonpolar solvents
oxygen atom bonded to
two alkyl groups
van der Waals forces
Section 3.7 Student Book Solutions
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8. Glycerol is an alcohol with a three-carbon chain, and a hydroxyl group on each carbon atom. The extra hydroxyl
groups form extra hydrogen bonds with water, which results in extra water molecules being held to the glycerol
molecules, keeping the water from freezing.
Making Connections
9. (a) IUPAC name: 1,2-dihydroxyethane
(b) Uses: most commonly used as an antifreeze, but also has many other product applications, including polyester
resin (PET), film and fibres, and heat transfer and hydraulic fluids.
(c) Properties: clear, colourless, odourless, viscous liquid with a sweet taste. Properties are a result of the two –OH
groups (sweetness) and the formation of hydrogen bonds (a viscous liquid with a fairly high melting point and
boiling point).
3.8 INVESTIGATION: PROPERTIES OF ALCOHOLS
PART 1: TRENDS IN PROPERTIES OF ALCOHOLS
(Pages 209–210)
Prediction
(a) Order of increasing melting points and boiling points: ethanol, 1-propanol, 1-butanol
Solubility in mineral oil (nonpolar solvent) and water (polar solvent): All three compounds are similarly soluble in
polar solvents and very slightly soluble in nonpolar solvents.
Acidity: All three alcohols are basic (blue in litmus).
Hypothesis
(b) Melting point and boiling point: Each alcohol has a single hydroxyl group, so each one has similar hydrogenbonding capabilities. The increasing size of the molecules increases the strength of the van der Waals forces, thus
increasing the melting and boiling points.
Solubility: Since each alcohol has a single hydroxyl group, each one will be similarly soluble in polar solvents. Since
they have small alkyl groups, they will be only slightly soluble, if at all, in nonpolar solvents.
Acidity: All three alcohols will also have similar basic properties due to the single hydroxyl group.
Observations
(c) and (d)
Property
Ethanol
1-Propanol
1-Butanol
melting point
–117ºC
–126ºC
–89ºC
boiling point
78ºC
97ºC
117ºC
solubility in mineral
oil
slightly soluble
slightly soluble
slightly soluble
solubility in water
soluble
soluble
soluble
colour with litmus
blue
blue
blue
structural formula
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Analysis
(e) Melting points and boiling points, from lowest to highest, are: ethanol, 1-propanol, 1-butanol
Solubility in nonpolar and polar solvents: All three alcohols are similarly soluble in polar solvents and very slightly
soluble in nonpolar solvents.
Acidity: All three alcohols turn blue in litmus.
(f) The observations agree with our predictions. Reasons are as follows:
• The increasing size of the molecules increases the strength of the van der Waals forces, thus increasing the
melting and boiling points.
• Since each alcohol has a single hydroxyl group, each will be similarly soluble in polar solvents. Since they have
small alkyl groups, they will be only slightly soluble, if at all, in nonpolar solvents.
• All three alcohols will also have similar basic properties due to the single hydroxyl group.
Synthesis
(g) Boiling points
1-butanol: 118°C
2-methyl-2-propanol: 83°C
1-hexanol: 157°C
2,2-dimethyl butanol: 121°C
Trends: the straight-chain alcohols have higher boiling points than branched-chain alcohols of similar molar mass
because there are more van der Waals forces of attraction between longer chains than between more spherically
shaped molecules of similar molar mass. Of the straight-chain alcohols, longer-chain molecules have higher boiling
points than shorter-chain alcohols because there are more van der Waals forces of attraction between longer chains
than between shorter chains.
(h) Linear molecules have more surface area, and therefore more intermolecular forces, than do spherical molecules;
therefore linear molecules have higher boiling points than spherical molecules of similar size.
PART 2: ALCOHOL AND ALKANE COMBUSTION
(Pages 210–211)
Prediction
(i) In the combustion of both ethanol and hexane, the products will be carbon dioxide and water.
Observations
(j) and (k)
Property
Ethanol
Hexane
organic family
alcohol
alkane
cobalt chloride test
positive
positive
limewater test
positive
positive
structural formula
Analysis
(l) The positive cobalt chloride test indicates that water is produced by both reactions. The positive limewater test
indicates that carbon dioxide is produced by both reactions.
C2H5OH + 3 O2 → 2 CO2 + 3 H2O
2 C6H14 + 19 O2 → 12 CO2 + 14 H2O
(m) Oxygen in the air must be allowed to enter the beaker to enable combustion to continue.
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Section 3.8 Student Book Solutions
141
Synthesis
(n) The wick burns at a higher temperature than ethanol and hexane, and thus will not burn until all the liquid has
completely burned and the heat is used to evaporate the fuel.
(o) The products in both reactions are the same. Alcohols are liquids and are more easily transported and stored than the
smaller hydrocarbons, which are generally gases. Gases must be compressed into liquids for storage. Compressed
gases are dangerous.
3.9 ALDEHYDES AND KETONES
TRY THIS ACTIVITY: WHERE’S THE CUP?
(Page 213)
(a) The bottom of the Styrofoam cup “disappears” as it is dissolved by the acetone.
(b) The IUPAC name for acetone is propanone. Acetone is polar due to its carbonyl group, and also nonpolar due to its
alkyl groups. This characteristic makes acetone miscible with both polar and nonpolar substances.
(c) Since Styrofoam dissolved in acetone, it probably has both polar and nonpolar characteristics.
SECTION 3.9 QUESTIONS
(Pages 213–214)
Understanding Concepts
1. In order of increasing boiling points: B, A, C. This order is predicted because A (1-propanone) contains a carbonyl
group (with a polar double bond), making it more polar than B (propane), which gives A a higher boiling point than
B. C (1-propanol) contains a hydroxyl group, which can hydrogen bond with other molecules, giving C a higher
boiling point than A or B.
2. In increasing order of solubility: C, A, B. C (butane) is a nonpolar hydrocarbon and is less soluble in water than A
(the ketone) and B (the alcohol). A has a polar carbonyl group, making it more soluble in water than C, but it is less
soluble than B, which has a hydroxyl group that allows it to hydrogen bond.
3. (a)
(b)
(c) Organic family
alcohol
ether
aldehyde
ketone
142
Functional group
hydroxyl group
oxygen bonded to two alkyl groups
carbonyl group at the end of the carbon chain
carbonyl group in the interior of the carbon chain
Unit 3 Student Book Solutions
NEL
4. Student answers for the examples will vary.
Front:
Family name
and general
formula
Examples
IUPAC name
Common name
Aldehydes
R−CHO
ethanal
acetaldehyde
Ketones
R-C(O)−R
propanone
acetone
Structural formula
Back:
Family
Characteristic properties
Characteristic
functional groups
Intermolecular
forces
Aldehydes
boiling points intermediate between
hydrocarbons and alcohols of similar
size; soluble in polar and nonpolar
solvents
carbonyl group at end
of carbon chain
van der Waals forces;
no hydrogen bonding
but highly polar
carbonyl group
produces strong
intermolecular forces
Ketones
boiling points intermediate between
hydrocarbons and alcohols of similar
size; soluble in polar and nonpolar
solvents
carbonyl group in
interior of carbon chain
van der Waals forces;
no hydrogen bonding
but highly polar
carbonyl group
produces strong
intermolecular forces
Making Connections
5. Examples include acetone, wood alcohol, rubbing alcohol, formaldehyde, natural gas, barbecue gas, lighter fluid, and
glycerin.
6. (a) methanal
(b) Formaldehyde is a flammable, poisonous, colourless gas with a suffocating odour. It readily polymerizes into
paraformaldehyde, a white solid that can be formed into candles and used for fumigating rooms. Formalin, the
preservative used in biological materials, is a solution of formaldehyde in water, with a small amount of
methanol added.
Other fluids used as preservatives include alcohol (the standard is 70–75% ethanol, or 40–50% 2-propanol);
Zenker’s fluid (containing mercury(II) chloride, glacial acetic acid, potassium dichromate, and sodium sulfate
in water).
7. [Sample Answer] Several chemists wanted to test the effect of pheromones on humans. They placed small samples
of male human pheromones under the chair seats of a number of chairs in a lecture hall just before the audience was
allowed in. Members of the audience were free to sit where they chose. As the chemists had predicted, each of the
“pheromone” seats was selected by a female. What are the odds of that? There are reportedly colognes and perfumes
available that contain potent concentrations of human pheromones, instead of the usual extracts of flowers and fruits,
which are better designed to attract insects and birds.
NEL
Section 3.9 Student Book Solutions
143
3.10 SAFE USE OF ORGANIC SOLVENTS
CAREER CONNECTION: FIREFIGHTERS
(Page 217)
(i) Pre-services courses are available in many communities in Ontario, mostly in community colleges (such as Northern
College in Timmins, Ontario). These courses can be taken on a part-time or full-time basis. Only after completing
this course would a candidate be considered for hiring by the various fire departments in Ontario. When hired, the
new firefighter is sent to the Ontario Fire College, in Gravenhurst, Ontario, to take the necessary courses to become a
qualified firefighter. (NOC code 6262)
(ii) The average wage for a new firefighter is $11.98 an hour (compared with the national average, for people of a
similar age, of $11.09). This wage advantage increases with experience, with a firefighter’s average hourly wage
being over $23 (national average about $17). Also, the unemployment rate for firefighters is below the national
average.
SECTION 3.10 QUESTIONS
(Page 217)
Understanding Concepts
1. Flammable liquids readily ignite and burn at normal working temperatures. Combustible liquids ignite and burn at
higher temperatures.
2. Student answers will vary.
Organic solvent
Use
Storage location
mineral spirits
paint thinners
garage
propanone (acetone)
nail polish remover
bedroom
2-propanol
rubbing alcohol
medicine cabinet in
bathroom
tetrachloroethene
(perchloroethylene), C2Cl4
stain remover
laundry room
Organic solvents should be stored away from other chemicals, in well-ventilated spaces and away from sunlight
or heat sources. They should not be stored in a basement or other below-ground locations. Organic solvents should
not be used close to heat sources or open flames, and only minimum required quantities should be transferred.
3. It means that, at –9°C, enough liquid solvent will vaporize and mix with air to form a mixture that will burn.
Applying Inquiry Skills
4. Use only the minimum amount needed. Return any unused ethanol to the proper storage container. Keep in a covered
container to reduce evaporation. Keep away from sunlight and other heat sources. Do not use near open flames or
electrical appliances that may produce a spark. Use in a well-ventilated area or in a fume hood. Avoid inhaling
vapours. Dispose of waste ethanol through hazardous waste collection.
Making Connections
5. Student answers will vary.
• No food or drink of any kind is allowed in a laboratory at any time.
• No open-toed shoes are allowed in the laboratory. Long hair and loose clothing must be tied back.
• Safety equipment, such as eye protection and lab aprons, must be worn as directed.
• Each laboratory is equipped with an eyewash station, a shower, fire extinguishers, fire blankets, and fume hood.
The locations of these items are clearly displayed.
• Material Safety Data Sheets are made available for all chemicals used or stored in the school.
• A ventilation system for the laboratory is required, and chemical storage cabinets for organic solvents and
oxidizing agents must be ventilated to the outside.
• A school emergency response team is in place to handle any hazardous situations.
• A hazardous waste disposal system is in place.
144
Unit 3 Student Book Solutions
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6. Student answers will vary, but should include the following recommendations.
• Carefully read and follow the recommendations on the MSDS for every chemical substance that you use.
• Be aware of the flammability and combustibility of solvents.
• Use organic solvents in a well-ventilated location, such as outdoors or a room with open windows, away from
ignition sources such as electrical sparks, open flames, and hot surfaces.
• Do not store organic solvents in direct sunlight, near heat sources, or in basements.
• Return any unused portions of solvents immediately to the appropriate storage containers.
• Dispose of waste solvents according to environmental restrictions; never pour them down the sink.
• Some solvents will spontaneously combust; for example, rags soaked in motor oil or linseed oil will ignite if they
are stuffed in a container such as a plastic pail. The rags should be hung outside on a clothesline, to allow any
heat that is produced to dissipate safely.
• Do not inhale any solvents.
3.11 CARBOXYLIC ACIDS
TRY THIS ACTIVITY: MAKING A BATH BOMB
(Page 219)
(a) citric acid + sodium hydrogen carbonate → sodium citrate + carbon dioxide + water
SECTION 3.11 QUESTIONS
(Page 220)
Understanding Concepts
1. (a)
(b) The hydroxyl group in this functional group is polar and can hydrogen bond, making the molecule soluble in
water. The carbonyl group is also polar and, with the hydroxyl group, increases intermolecular attractions and
thus raises the melting and boiling points of carboxylic acids.
2. Carboxylic acids contain the carboxyl group, which consists of a carbonyl group and a hydroxyl group. Both
carbonyl groups and hydroxyl groups are polar groups, resulting in carboxylic acids being polar molecules.
3. (a)
ethanoic acid
oxalic acid
(b) Oxalic acid is a solid at room temperature because, as it is polar, the van der Waals forces between the
molecules are stronger than those in ethanoic acid (vinegar). There is also more opportunity for hydrogen
bonding among molecules.
4. The gas (A) has the lowest boiling point and must be an alkane, the least polar molecule. The liquid (B) has the next
highest boiling point and must be the alcohol, which has a hydroxyl group.
NEL
Section 3.11 Student Book Solutions
145
5. Student examples will vary.
Front:
Family name and
general formula
Examples
IUPAC name
Common name
Carboxylic acids
R−COOH
ethanoic acid
acetic acid (vinegar)
Structural formula
Back:
Family
Characteristic properties
Characteristic
functional groups
Intermolecular forces
Carboxylic acids
soluble in water, turn litmus pink, react
with alcohols to form esters
carboxyl group
−COOH
hydrogen bonds, van
der Waals forces
6.
Applying Inquiry Skills
7. Melting and boiling points: The ketone is more likely a liquid at room temperature, while the carboxylic acid is more
likely a solid. The carboxyl group in the acid is polar and also can hydrogen bond, while the ketone does not contain
the hydroxyl group.
Litmus and pH test: Carboxylic acids turn litmus red, an acidic pH.
3.12 INVESTIGATION: PROPERTIES OF CARBOXYLIC ACIDS
(Pages 221–222)
Prediction
a) [Sample answer] Stearic acid has a much longer hydrocarbon chain than does acetic acid. Thus, stearic acid is more
nonpolar than acetic acid and will be less soluble in a polar solvent such as water, and more soluble in a nonpolar
solvent such as vegetable oil. Stearic acid will also have a higher melting point because its long hydrocarbon chain
allows intermolecular forces of attraction (van der Waals forces). Acetic acid will react readily with the basic
solution, but stearic acid will react less readily because it is less soluble in the aqueous solution of the base.
146
Unit 3 Student Book Solutions
NEL
Observations
(b) to (e)
Table 1 Properties of Carboxylic Acids
Property
Acetic acid
Stearic acid
molar mass
60.05 g/mol
284.50 g/mol
melting point
16.7ºC
69ºC
boiling point
118ºC
383ºC
solubility in water
soluble in water
low solubility in water
solubility in
vegetable oil
low solubility in vegetable oil
soluble in vegetable oil
reaction with
base
reacts with base
does not readily react with base
structural formula
Analysis
(f) Both acids contain the polar carboxyl group. In addition, stearic acid has a long hydrocarbon group with stronger van
der Waals attractions than in the shorter ethanoic acid. For this reason, stearic acid has a higher melting point and
boiling point than ethanoic acid.
(g) Acetic acid is more soluble in water than is stearic acid, and less soluble in oil. Stearic acid, with its long
hydrocarbon component, has a longer nonpolar component and is thus more soluble in the nonpolar oil.
(h) Acetic acid reacts with sodium hydrogen carbonate, as acids do. Stearic acid is not soluble in water and does not
show a reaction with aqueous sodium hydrogen carbonate.
Evaluation
(i) [Sample answer] Yes, the Procedure allowed the collection of appropriate evidence regarding all aspects of this
investigation, except for the reaction with sodium hydrogen carbonate. Since stearic acid was not highly soluble in
water, it is inconclusive whether it reacts with sodium hydrogen carbonate.
(j) [Sample answer] Answers obtained in the Analysis are in agreement with the Prediction. The theoretical model of
carboxylic acids helped to predict the chemical properties of these acids. The effect of the polar and nonpolar
components of each acid could be used to predict physical and chemical properties of the compounds.
3.13 ESTERS
SECTION 3.13 QUESTIONS
(Page 225)
Understanding Concepts
1. An ester contains an –OR group in place of the –OH group in the carboxylic acid. Both carboxylic acids and esters
contain a carbonyl group.
NEL
Section 3.13 Student Book Solutions
147
2. Carboxylic acids contain a carbonyl group and a hydroxyl group (together making up the carboxyl group). Esters
also contain a carbonyl group, but not the hydroxyl group. Since both groups contribute to the polarity of the
molecule, esters are less polar than are carboxylic acids, and are therefore less soluble in water.
3. In esterification, an organic acid and an alcohol react to produce an ester and water. In the reaction between the
inorganic acid HCl and the inorganic base NaOH, a salt, NaCl, and water are produced. Thus, an esterification is
similar to a neutralization reaction between inorganic acids and bases.
4. A hydrolysis reaction is a reaction in which a bond is broken by the addition of the components of water, forming
two or more products. An ester can undergo a hydrolysis reaction to form an acid and an alcohol. It may be
considered the reverse of an esterification reaction.
5. Student examples will vary.
Front:
Family name
and general
formula
Examples
IUPAC name
Common name
Esters
R–COO–R
methyl propanoate
(none)
Structural formula
Back:
Family
Characteristic properties
Characteristic
functional groups
Intermolecular
forces
Esters
less soluble in water than their
parent acids; lower melting and
boiling points than parent acids;
not acidic; often have distinctive
odours, e.g., fruity, peppermint.
R–COO–R
van der Waals
forces
Applying Inquiry Skills
6. Students should give three suggestions.
(i) Test each liquid with litmus. The carboxylic acid will turn blue litmus pink, while the ester will not.
(ii) Add water to each liquid. The carboxylic acid dissolves readily in water, while the ester dissolves less readily.
(iii) Determine the boiling point of each liquid by heating gently in a fume hood until it starts to boil. The carboxylic
acid has a higher boiling point than does the ester.
(iv) Carefully waft each liquid to detect any odour. Esters generally have distinctive odours.
Making Connections
7. (a)
148
Unit 3 Student Book Solutions
NEL
(b) Animal hides decompose quickly unless they are cured to remove the water from the skin. The hide is first
soaked in water to remove water-soluble substances. Hair is removed by soaking the hide in a mixture of lime
and water, followed by an enzyme mixture. The hair and any remaining tissue is removed by machine, and the
hide is washed and treated with tannic acid. The tannic acid displaces water from the spaces between the hide’s
protein fibres, allowing the fibres to cement together to form strong water-resistant leather.
3.14 ACTIVITY: SYNTHESIS OF ESTERS
(Pages 226–227)
Analysis
(a) Table 2 Summary of Condensation Reactions
Reaction 1
Reaction 2
Reaction 3
IUPAC name of alcohol used
ethanol
2-propanol
1-pentanol
Structural formula of alcohol used
CH3CH2OH
CH3CH(OH)CH3
CH3CH2CH2CH2CH2OH
IUPAC name of carboxylic acid used
ethanoic acid
ethanoic acid
ethanoic acid
Structural formula of
carboxylic acid used
CH3COOH
CH3COOH
CH3COOH
IUPAC name of ester produced
ethyl ethanoate
isopropyl ethanoate
pentyl ethanoate
Structural formula of ester produced
CH3COOCH2CH3
CH3COOCHCH3CH3
CH3COOCH2CH2CH2CH2CH3
Odour of ester produced
fruity
fruity
banana
(b)
Reaction in Tube #1
Reaction in Tube #2
Reaction in Tube #3
(c) The concentrated sulfuric acid acts as a catalyst.
(d) The esters are insoluble in aqueous solution because each ester formed a layer on top of the cold water in the
evaporating dish. This effect is caused by the loss of the hydroxyl group from the carboxyl group when the ester
bond is formed. Thus, the ability to hydrogen bond with water is lost.
NEL
Section 3.14 Student Book Solutions
149
3.15 AMINES AND AMIDES
SECTION 3.15 QUESTIONS
(Page 230)
Understanding Concepts
1. An –OH group is removed from the carboxylic acid and an –H is removed from the amide to produce a water
molecule.
2. Amines contain –NH groups, which are less polar than –OH groups in alcohols, and are less capable of hydrogen
bonding than are –OH groups, which accounts for the lower boiling points of amines.
3. (a) amine
(b) amide
4. (a) alcohol, amine; The –OH group in alcohols is more polar than the –NH group in amines, making alcohols less
soluble in nonpolar solvents than amines.
(b) hydrocarbon, amine; Bonds between N and C are more polar than bonds between H and C. Therefore, amines
are slightly more polar than hydrocarbons, making them less soluble in nonpolar solvents. However, if the
nonpolar groups are large, the increased attraction between nonpolar groups may make amines more soluble in
nonpolar solvents.
5. Length of nonpolar hydrocarbon component: CH3CH2CH2CH2CH3
Presence of double or triple bonds: CH2=CH2, CH3C{CCH3
–OH groups: CH3CH2OH
–NH groups: H2NCH3
C=O bonds: CH3CHO, CH3COOH
6. Student examples will vary.
Front:
Family name and
general formula
Examples
IUPAC name
Common name
Amines
1-aminopropane
(none)
Amides
ethanamide
(none)
Structural formula
Back:
150
Family
Characteristic properties
Amines
often have unpleasant odours; react
with carboxylic acids to form amides;
have higher boiling points and melting
points than similar-sized
hydrocarbons, lower boiling points and
melting points than similar-sized
alcohols; smaller amines are readily
soluble in water
Hydrogen bonds due
to any –NH groups;
van der Waals forces
due to polar C–N
bonds
Amides
generally insoluble in water
Hydrogen bonding due
to –NH groups
Unit 3 Student Book Solutions
Characteristic
functional groups
Intermolecular forces
NEL
7. (a) Each small unit must contain an amino group and a carboxyl group, so that an amide bond can form between
small units.
(b) Because they have both amino groups and carboxyl groups, amino acids are likely fairly soluble in water and
are capable of forming strong amide bonds.
Making Connections
8. The carboxylic acids, such as citric acid in lemons and acetic acid in vinegar, react with the amines responsible for
the fishy taste in fish to produce amides, thereby reducing the smell. For example,
3.16 EXPLORE AN ISSUE: REGULAR OR DIET?
Understanding the Issue
(Page 232)
1. cyclamates, saccharin, aspartame
2. (a) People who are trying to reduce their food energy intake, or who are living with diabetes, can still enjoy
sweetened drinks and foods. Also, artificially sweetened products do not contribute to tooth decay.
(b) People who use artificial sweeteners are not avoiding highly sweetened foods and drinks, so are likely to
continue to consume them, whether sweetened naturally or artificially. Consuming sweetened foods may lead to
continued weight gain and tooth decay. Furthermore, studies indicate that artificial sweeteners may be bad for
your health.
3. (a)
Maspartame = 294.34 g/mol
(b) Maspartame = 294.34 g/mol
The portion in the aspartame molecule attributable to methanol is CH3O.
mCH O = 31.04 g
3
31.04 g
× 100%
294.34 g/mol
%CH3O = 10.55%
M
(c) mCH OH = 200 mg × CH 3OH
3
Maspartame
32.05 g/mol
= 200 mg ×
294.34 g/mol
mCH OH = 21.8 mg
%CH3O =
3
NEL
Section 3.16 Student Book Solutions
151
(d) LD50(70 kg) = 0.07 g/kg u 70 kg
LD50(70 kg) = 4.9 g = 4900 mg
(e) number of cans of diet pop =
4900 mg
21.8 mg/can
= 220 cans
TAKE A STAND: HEALTH BENEFIT OR HEALTH HAZARD?
(Page 232)
(a) Student answers will vary.
Aspartame:
Reasons for its use: reducing caloric intake, to counter obesity; for sugar-reduced or sugar-free diets, e.g., for
diabetic patients; to reduce incidence of tooth-decay
(b) Student answers will vary.
Factors to consider: experimental design, e.g., use of controlled variables; type of system tested, e.g., tests done on
mice, and the information transferred to human applications; size of population tested; number of independent
research groups reporting findings; funding of the research group, e.g., whether the research is funded by the
manufacturer of the product.
(c) [Sample answer] Risks are still uncertain and debatable. In some cases, benefits outweigh the risks, as in sugar-free
diets prescribed by doctors. In other cases, any possible risk should be reduced by minimizing the daily use of
aspartame.
3.17 ACTIVITY: CLASSIFYING PLASTICS
(Pages 233–236)
Observations
(a)
Table 2 Summary of Observations and Possible SPI Codes (sample answer)
Sample
tested
Density
Flame
colour
Acetone
Melting
Possible SPI
code
1
floats in water, in alcohol
solution, and in corn oil
code 5:
PP
2
floats in water and in alcohol
solution, and sinks in corn oil
code 4:
LDPE
3
floats in water, and sinks in
alcohol solution
code 2:
HDPE
4
sinks in water
green
5
sinks in water
not green
increased softness
in acetone
6
sinks in water
not green
no increased
softness in acetone
code 3:
PVC
code 6:
PS
increased softness
in boiling water
code 1:
PETE
Analysis
(b) Part 1
In water: Samples that float may be resin codes 2, 4, or 5 (less dense than water, whose density is 1 g/mL). Samples
that sink may be resin codes 1, 3, or 6.
In alcohol solution: Samples that float may be resin codes 4 or 5 (less dense than alcohol solution). Samples that
sink may be resin code 2.
In oil: Samples that float may be resin code 5 (less dense than resins 4 and 5). Samples that sink may be resin
code 4.
Part 2
Flame test: Of possible resin codes 1, 3, or 6, resin code 3 contains chlorine atoms. The sample that produces a green
flame is resin code 3.
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Unit 3 Student Book Solutions
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Part 3
Acetone test: Of possible resin codes 1 or 6, resin code 6 softens in acetone. The samples that soften in acetone are
resin code 6. The samples that did not soften may be resin code 1.
Part 4
Melting test: This sample may have resin code 1. If the sample softens in boiling water, it has resin code 1.
Evaluation
(c) [Sample answer] Repeat the procedure using known resin samples, codes 1 to 6, to confirm test results.
Synthesis
(d) Student answers will vary.
Recycling operation at school
• Types of materials collected: paper, plastic water bottles, plastic pop bottles, glass drink bottles, aluminum cans
• Amounts: approximately four large garbage bags of paper each week, five large garbage bags of each type of
bottle and cans each week
• Participation rate: approximately 30% of students recycle
• Problems encountered: “recycling containers” do not keep bottles and cans separate, so bottles and cans need to
be sorted by hand; collection containers also contain garbage, sometimes making collected materials unusable
• Destination: collected by city recycling facility; some items are destined for sorting locally, and some items are
transported to a large city nearby
(e) Issues related to use of plastics:
• There is a growing demand for petroleum as raw materials for the manufacture of plastics.
• Petroleum, a fossil fuel, is a non-renewable resource that cannot be replaced when the source is exhausted.
• Most plastic products are non-biodegradable; that is, these products, when discarded, occupy large areas of land
for an indefinite length of time. Since they do not decompose, the atoms and molecules in plastics are not
returned to the environment to be used in other systems.
Suggestions for non-synthetic substitutes:
• cotton fibres instead of polyester
• reusable metal cutlery instead of plastic
• washable glasses instead of Styrofoam cups
• washable cloth diapers instead of disposable synthetic polymers
(f) Student answers will vary. Posters should show types of recycled products, flow charts of recycling resources,
benefits to environment, location and dates of collections.
(g) Student answers will vary.
• PET: 56% of recycled PET is made into fibre for carpet and clothing, 13% into strapping, and 14% into food or
non-food containers.
• HDPE: 29% of recycled HDPE (mostly from bottles) is made into new bottles. HDPE is also recycled into lawn
and garden products, such as flowerbed edging, and into plastic lumber for use in decks, benches, and picnic
tables.
(h) Student answers will vary, but may include one of the following careers: recycling truck driver, planner for
recycling routes, organizer of recycling facility. Other related fields include environmental enforcement, policy and
planning, community relations, and other support services.
Qualifications and training to be a waste systems manager:
• an understanding of environmental issues
• a background in environmental studies or waste management, or a degree in public administration
• courses or qualifications in finance
3.18 POLYMERS
TRY THIS ACTIVITY: SKEWERING BALLOONS
(Page 238)
(a) The intermolecular attractions between polymer chains allow the long molecules to move aside to allow the skewer
to push through without breaking, analogous to the noodles moving over each other.
NEL
Section 3.18 Student Book Solutions
153
SECTION 3.18 QUESTIONS
(Page 242)
Understanding Concepts
1. carbon–carbon double or triple bonds
2. (a) intermolecular forces: van der Waals forces, electrostatic attractions due to any substituted groups present, and,
if crosslinking occurs, covalent bonds.
(b) Properties of the plastics can be designed and controlled by the type of monomer used, and the type of bonding
present in the polymer. The polymers are stronger than the monomers, and can be moulded by various
processes, depending on the degree of crosslinking.
(c) The double bonds in the monomers are replaced by single bonds in the polymers, resulting in the polymer
having properties more similar to the less reactive alkanes than to the alkenes of the monomers.
3. The monomer must have more than one double bond for crosslinking to occur between polymer chains
(e.g., 1,3-pentadiene).
CH2=CHCH=CHCH3
4. Two functional groups that can undergo condensation reactions, e.g., a carboxyl group, and either a hydroxyl group
or an amino group, must be present in the monomer of a condensation polymer.
5. Covalent bonding occurs within a polyamide chain. Van de Waals forces, and hydrogen bonding if N–H bonds are
present, occur between polyamide chains.
6. (a) Plastics are typically flexible, lightweight, mouldable, and electrically nonconductive. Plastics also soften when
heated.
(b) Within long polymer molecules, you would expect to find covalent bonds. Intermolecular bonds are van der
Waals forces. Covalent bonds between molecules would exist if crosslinking were present.
(c) Intramolecular bonding: The prevalence of single, rather than multiple, carbon–carbon bonds makes plastics
strong and chemically unreactive. Intermolecular bonding: Intermolecular forces and crosslinking make plastics
strong, flexible, and mouldable. The more crosslinks there are, the more rigid the plastic is.
7. A polyester is linked by functional groups that form esters: carboxyl groups and hydroxyl groups (e.g., polyester).
A polyamide is linked by functional groups that form amides: carboxyl groups and amino groups (e.g., nylon).
8. (a) Covalent bonds: intrachain bonds joining C, H, O, and N atoms.
(b) Amide bonds: the linkage between the N of the amino group of the amine and the C of the carbonyl group of the
acid.
(c) Hydrogen bonds: interchain attractions between –NH groups and carbonyl groups.
Making Connections
9. (a) HOOC−CH2CH2CH2CH2−COOH + H2N−CH2CH2CH2CH2CH2CH2−NH2
→ −OC−CH2CH2CH2CH2−CONH−CH2CH2CH2CH2CH2CH2−NH−
(b) The numbers refer to the number of carbon atoms in the monomers. Nylon 6,6 refers to 6 carbon atoms in each
of the two monomers used.
Applying Inquiry Skills
10. (a) An ideal polymer would be able to absorb sufficient water to sustain a plant for several weeks, absorb nutrients
dissolved in water, would not be harmful to plants, and could be tailored to specific types of applications (e.g.,
houseplants, outdoor plants). Also, ideal polymers would degrade after several months into harmless products,
and would be inexpensive.
(b) To test for absorption, place samples of equal mass of each polymer in equal volumes of excess water and
excess water with dissolved nutrients. Determine the mass of liquid absorbed. To test for the release of liquid,
mix equal swelled masses of each polymer with equal masses of a variety of soil types, and measure the
moisture content over a test period. Store the mixture samples over several months and determine the amount of
degradation. As a safety precaution, test pH. An appropriate test period would be two weeks.
Sample answer:
(i)
154
Polymer
Mass of polymer
Mass of water
added
Mass of polymer and absorbed
water
polymer A
50.0 g
100.0 g
70.0 g
polymer B
50.0 g
100.0 g
80.0 g
Unit 3 Student Book Solutions
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(ii)
Polymer
Mass of nutrient
solution absorbed
% change in concentration of nutrients in
excess solution
polymer A
50.0 g
100.0 g
polymer B
50.0 g
100.0 g
Polymer
Mass before
degradation
Mass after degradation (8 weeks)
pH
polymer A
50.0 g
25.0 g
pH 5.5
polymer B
50.0 g
40.0 g
pH 6.5
(iii)
Analysis
Polymer A absorbed less fluid than polymer B, and did not absorb nutrients as well as polymer B. Polymer A also
degraded to produce acidic substances. Polymer B allowed all nutrients to be absorbed but did not degrade as quickly as
polymer A.
11. (a) [Sample answer] The following types of plastic products are accepted: code 1 (bottles for carbonated drinks,
containers for peanut butter, salad dressings); code 2 (milk cartons, water bottles, juice bottles, grocery bags);
code 4 (dry-cleaning and grocery bags, flexible containers and lids); code 5 (ketchup bottles, margarine
containers); code 6 (meat trays, plastic knives, spoons, forks). Code 3 is not accepted by municipal recyclings
services because these items are too large for pickup or contain medical hazards in medical tubing, etc. Some
construction pipes, siding, window frames, etc., are accepted by nonprofit environmental programs. Students
will need to check their local recycling program for specific information. Table headings: SPI resin code; Type
of products; Properties; Accepted by Municipal Recycling Organization; Accepted by Other Recycling
Organization.
(b) and (c)
Common name
of plastic
Monomer
Molecular structure
vinyl
ethene
[–CH2–CH2–CH2–CH2–]n
Saran wrap
1,1-dichloroethene
[–CH2–CCl2–CH2–CCl2–]n
acrylic
CH2=CH–CN
[–CH2–CH(CN)–CH2–C(CN)–]n
polystyrene
styrene
[–CH2–CH(Ø)–CH2–C(Ø)–]n
Polyvinylchloride
(PVC)
chloroethene
[–CH2–CHCl–CH2–CHCl–]n
12. (a) [Sample answer] Strong, flexible, chemically unreactive, insoluble in polar and nonpolar solvents, not softened
by heat, nonbiodegradable
(b) [Sample answer] Presence of F or Cl atoms, controlled degree of crosslinking to obtain desired flexibility and
strength, resistance to heat
13. Natural rubber is produced from the sap of the rubber tree, Hevea brasiliensis. The sap is collected, exposed to air,
and gently heated. Natural rubber is a polymer of 2-methyl-1,3-butadiene (isoprene), CH2=C(CH3)–CH=CH2. The
polymerization reaction is nCH2=C(CH3)–CH=CH2 → –[CH2–C(CH3)=CH–CH2]n–
Charles Goodyear developed the vulcanizing process in which rubber is heated with sulfur. This process
produced a more reactive and stable rubber and made it suitable for a wide range of products, such as cushions,
mattresses, raincoats, and shoes. Rubber is primarily used in car tires. A filler, such as carbon black, is added for
reinforcement. Synthetic rubber was developed and produced in Germany during the First World War, and demand
for materials increased research and production of new synthetic rubbers during the Second World War.
14. [Sample answers] This polymer would also be useful as a potting soil additive for moisture retention, as a filter for
removing traces of moisture from gasoline and oil, as a time-release drug delivery system, and as material for “grow
a dinosaur” type toys.
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Section 3.18 Student Book Solutions
155
3.19 TECH CONNECT: THE NICOTINE PATCH
SECTION 3.19 QUESTIONS
(Page 243)
Understanding Concepts
1. (a) Because the skin has both water-soluble (polar) and fat-soluble (nonpolar) components, any drug molecule that
travels through the skin must be a suitable size and must be soluble in both polar and nonpolar solvents.
(b) The carbon rings and the methyl group are the nonpolar components of the nicotine molecule. The nitrogen
atoms are more electronegative than the carbon atoms, and thus provide a polar portion of the molecule. Thus,
nicotine has both polar and nonpolar characteristics, and its size is sufficiently small to allow it to travel through
the skin.
Making Connections
2. [Sample answer]
Drug delivery systems, e.g., nicotine patches, estrogen patches.
Problem to be solved: Patients quitting smoking need a bridging program to relieve withdrawal from nicotine.
Patients require estrogen to relieve symptoms of menopause due to surgery.
Existing solution: nicotine gum, estrogen capsules.
Problems: Patients may forget to take medication. As well, a low but continuous dosage is most effective.
Improved solution: Polymers could be used to provide an adhesive patch on the skin, allowing the nicotine or
estrogen to be absorbed through the skin on a continuous basis.
3. Student answers will vary.
The Estrogen Skin Patch
The skin patch is used in hormone replacement therapy, to deliver the hormone estrogen to women to relieve some
of the symptoms of menopause. Estrogen can also be taken in pill form, but some studies have indicated that
estrogen pills can cause an increase in the body’s production of a substance called C-reactive protein. This protein
seems to increase the risk of heart disease. Another study indicated that the increase in C-reactive protein was twice
as high if the estrogen was taken in pill form as opposed to as a skin patch. A possible explanation for this difference
is that the active components in an estrogen pill must be metabolized by the liver before they enter the blood stream.
The skin patch delivers the estrogen in a useable form directly to the blood stream, so lower dosages are needed. The
disadvantages of the skin patch are that the adhesive and the moist conditions under the patch may, over an extended
period of use, cause skin irritations. In addition, some people may have allergic reactions to one of the components
of the patch. Other preferable methods of replacing estrogen may be from natural foods that are rich in estrogen,
such as soybean products in the form of soymilk or tofu.
3.20 ACTIVITY: MAKING POLYMERS
(Pages 244–246)
PART 1: MAKING GUAR GUM SLIME—A CROSSLINKED POLYMER
Observations
(a) The slime stretches and then returns to its original shape. It is stretchable and flexible.
(b) The slime breaks.
(c) The slime breaks with a sharp surface at the break.
(d) The slime takes on the shape of a long string.
(e) The slime softens and starts to liquefy.
Analysis
(f) (a) Crosslinking holds polymer strands together. Any deformation of the slime is restored by the crosslinks between
polymer strands.
(b) Crosslinks are broken by sharp pulling of the polymer.
(c) Sharp force on the slime breaks all the crosslinks along the line of force, leaving the slime broken with a sharp
surface.
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Unit 3 Student Book Solutions
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(d) As the slime passes gently through the hole of the funnel, some crosslinks are broken and reformed, leaving the
polymer with a new shape.
(e) The presence of an acid hydrolyzes the crosslinks, causing the slime to turn into a liquid.
Synthesis
(g)
Thickener
Source
Molecular structure
Reasons for similar
properties
Cornstarch
germ of corn kernels
polysaccharides: amylose
and amylopectin
Carrageenan
varieties of red seaweed
long-chain carbohydrate
polymer (polysaccharide)
made up of repeating sugar
units
Gelatin
beef bones and skin,
treated with bases
protein polymer made up of
amino acids
These polymers react with
water, usually when
heated, to form hydrated
crosslinked molecules
throughout the solution,
resulting in a thickening of
the solution.
PART 2: MAKING GLYPTALA POLYESTER
Observations
(h) Glyptal is a hard clear plastic. It gets marred in contact with organic solvents such as acetone because it is soluble in
acetone.
Analysis
(i) Sample properties: hard, clear, strong solid; insoluble in water but soluble in acetone (paint thinner or nail polish
remover).
Synthesis
(j) It hardens quickly to form a protective coating that is insoluble in water. It is miscible with organic solvents that may
be present in paints.
(k) This polymer could also be used in varnishes and as a substitute for glass (e.g., plastic containers, drinking glasses).
(l) The hydroxyl group on the middle carbon of glycerol provides opportunity to form ester bonds with orthophthalic
acid, forming strong crosslinks. A hard plastic is therefore formed, which does not soften when heated. The
hydrocarbon portions of the plastic molecule provide nonpolar groups, making the plastic insoluble in water, but
soluble in an organic solvent such as acetone.
3.21 CASE STUDY: CONTACT LENSES
SECTION 3.21 QUESTIONS
(Page 248)
Understanding Concepts
1. When a polymer is deformed, its polymer chains are forced out of alignment. Crosslinking pulls the polymer chains
back together, returning the lens to its original shape.
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Section 3.21 Student Book Solutions
157
Making Connections
2. [Sample answer] This statement is valid. Properties of polymers can be changed by altering the type of functional
groups and substituted groups on the monomers, and by altering the type of interchain linkages. There are numerous
organic compounds that can act as monomers because carbon atoms can form four bonds and long carbon chains.
3. (a) Hard lenses: Plastic lenses (PMMA) replaced glass lenses for comfort, but did not allow sufficient oxygen to
reach the eye. Soft lenses: PolyHEMA replaced hard contact lenses. Soft lenses are more comfortable and have
improved oxygen permeability, but they are not long-lasting because they are easily deformed. Rigid gaspermeable lenses are made of a new polymer that is gas permeable and retains its shape; however, there is an
increased risk of protein and lipid deposits on the lens.
(b) New polymers were developed for rigid gas-permeable lenses, and research is ongoing to develop new organic
compounds with desired properties for use in improving vision and eye care.
4. [Sample answers] Desirable features include lenses that are gas permeable, rigid, and easy to maintain, that can be
worn for long periods of time. Future developments depend on the design and testing of polymers with different
functional groups and substituted groups, and varying degrees of crosslinking.
5. (a) [Sample answers] Some crosslinking gives the lens elasticity and comfort for the wearer; however, elasticity is
at the expense of the lens retaining its shape for correcting vision. High water content in the lens is needed to
provide oxygen to the eye; however, increased water content decreases the refractive index of the lens and
lowers the corrective effect.
(b) [Sample answer] Some polymer molecules such as transparent plastics; some degree of crosslinking to provide
rigidity as well as flexibility, and to keep shape with body temperature; selected functional groups that allow
interaction with water but do not dissolve.
Extension
6. [Sample answer]
Drug delivery systems, e.g., nicotine patches, estrogen patches.
Problem to be solved: Patients quitting smoking need a bridging program to relieve withdrawal from nicotine;
patients requiring estrogen to relieve symptoms of menopause.
Existing solution: nicotine gum, estrogen capsules.
Problems: patients may forget to take medication. As well, a low but continuous dosage is most effective.
Improved solution: Polymers may be used to provide an adhesive patch on the skin, allowing the nicotine or estrogen
to be absorbed through the skin on a continuous basis.
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Unit 3 Student Book Solutions
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UNIT 3 SUMMARY
MAKE A SUMMARY
(Page 251)
(a)
Front:
Family name and general
formula
Examples
IUPAC name
Common name
Alkanes
CnHn+2
butane
lighter fluid
Alkenes
CnHn
propene
propylene
Alkynes
CnHn–2
ethyne
acetylene
Structural formula
Back:
Family
Characteristic properties
Alkanes
smaller molecules are gases at
no functional groups; all C−C
room temperature, larger
bonds are saturated
molecules tend to be liquids or soft
solids; soluble in nonpolar
solvents; generally unreactive
van der Waals forces
Alkenes
smaller molecules are gases at
C=C
room temperature, larger
molecules tend to be liquids or soft
solids; soluble in nonpolar
solvents; undergo addition
reactions
van der Waals forces
Alkynes
smaller molecules are gases at
C{C
room temperature, larger
molecules tend to be liquids or soft
solids; soluble in nonpolar
solvents; undergo addition
reactions
van der Waals forces
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Characteristic functional
groups
Intermolecular forces
Unit 3 Summary Student Book Solutions
159
Front:
Family name and
general formula
Examples
IUPAC name
Common name
Alcohols
R−OH
2-butanol
none
Ethers
R−O−R
ethoxypropane
none
Structural formula
Back:
Family
Characteristic properties
Characteristic
functional groups
Intermolecular forces
Alcohols
soluble in water and some nonpolar
solvents; react with carboxylic acids to
form esters
hydroxyl group
hydrogen bonds
Ethers
soluble in nonpolar solvents
oxygen atom bonded to
two alkyl groups
van der Waals forces
Front:
Family name and
general formula
Examples
IUPAC name
Common name
Aldehydes R−CHO
ethanal
acetaldehyde
Ketones
R–C(O)−R
propanone
acetone
Structural formula
Back:
Family
Characteristic properties
Characteristic
functional groups
Intermolecular forces
Aldehydes
boiling points intermediate between
hydrocarbons and alcohols of similar
size; soluble in polar and nonpolar
solvents
carbonyl group at end of
carbon chain
van der Waals forces;
no hydrogen bonding
but highly polar
carbonyl group
produces strong
intermolecular forces
Ketones
boiling points intermediate between
hydrocarbons and alcohols of similar
size; soluble in polar and nonpolar
solvents
carbonyl group in interior
of carbon chain
van der Waals forces;
no hydrogen bonding
but highly polar
carbonyl group
produces strong
intermolecular forces
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Unit 3 Student Book Solutions
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Front:
Family name and
general formula
Examples
IUPAC name
Common name
Carboxylic acids
R−COOH
ethanoic acid
acetic acid (vinegar)
Structural formula
Back:
Family
Characteristic properties
Characteristic
functional groups
Intermolecular forces
Carboxylic acids
soluble in water, turn litmus pink, react
with alcohols to form esters
carboxyl group
hydrogen bonds,
van der Waals forces
−COOH
Front:
Family name and
general formula
Examples
IUPAC name
Common name
Esters
RCOOR
methyl propanoate
(none)
Structural formula
Back:
Family
Characteristic properties
Characteristic
functional groups
Intermolecular forces
Esters
less soluble in water than their parent
acids; lower melting and boiling points
than parent acids; not acidic; often have
distinctive odours, e.g., fruity,
peppermint
R–COO–R
van der Waals forces
Front:
Family name and
general formula
Examples
IUPAC name
Common name
Amines
1-aminopropane
(none)
Amides
ethanamide
(none)
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Structural formula
Unit 3 Summary Student Book Solutions
161
Back:
Family
Characteristic properties
Characteristic
functional groups
Intermolecular forces
Amines
often have unpleasant odours; react with
carboxylic acids to form amides; have
higher boiling points and melting points
than similar-sized hydrocarbons, lower
boiling points and melting points than
similar-sized alcohols; smaller amines
are readily soluble in water
hydrogen bonds due to
any –NH groups; van
der Waals forces due to
polar C–N bonds
Amides
generally insoluble in water
hydrogen bonds due to
any –NH groups
UNIT 3 PERFORMANCE TASK: MAKING SOAP
(Pages 253–255)
Analysis
(a) The functional groups of glycerol are all hydroxyl groups, –OH. Glycerol is therefore an alcohol. It forms hydrogen
bonds in addition to van der Waals forces.
(b) The functional group of stearic acid is the carboxyl group, –COOH, made up of a carbonyl group and a hydroxyl
group. Stearic acid is a carboxylic acid. It forms hydrogen bonds in addition to van der Waals forces due to the polar
carbonyl groups. Stearic acid has low solubility in water because its long hydrocarbon chain “nullifies” the polarity
of the carboxyl group, rendering it a more nonpolar molecule that has low solubility in a polar solvent.
(c) Water is formed. Therefore, this reaction is a condensation reaction.
(d)
ethanoic acid (acetic acid)
CH3COOH(aq) + NaOH(aq) → CH3COONa(aq) + H2O(l)
Evaluation
(e) [Sample answer] The soap did not harden; it remained greasy. We perhaps need to use more NaOH(aq). The soap did
not lather very well. It is possible that using distilled water in the procedure would solve this problem.
Synthesis
(f) We would predict that glycerol has a higher boiling point than 1-propanol because glycerol has three hydroxyl
groups and 1-propanol has one. Glycerol would therefore form more hydrogen bonds than would 1-propanol, and
thus more energy is required to separate the glycerol molecules to form a gaseous state.
(g) Glycerol is probably soluble in polar solvents because of the polar hydroxyl groups. It may be slightly soluble in
nonpolar solvents because of the three-carbon backbone.
(h) Carbon dioxide and water would form as a result of the combustion of glycerol:
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Unit 3 Student Book Solutions
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(i) Use organic solvents in a well-ventilated location or fume hood, away from ignition sources such as electrical
sparks, open flames, and hot surfaces. Do not store solvents in direct sunlight or near heat sources, or in basements.
Return unused portions immediately to the appropriate storage containers. Dispose of small amounts of ethanol
(according to environmental restrictions) in the sink, followed by plenty of water.
(j) Detergents are made from long hydrocarbon chains and sulfuric acid. They are similar to soap molecules, which also
have long carbon chains and a salt group at one end. Advantages of detergents are that they do not produce an
insoluble “scum” with the calcium and magnesium ions in hard water, and they are generally less expensive than
soap. Disadvantages of detergents are that they are generally not biodegradable and may damage the environment.
They are made from non-renewable petroleum products.
UNIT 3 REVIEW
(Pages 256–259)
Understanding Concepts
1. (a) HC≡CH
(b) CH3CH(OH)CH3
(c)
(d) CH3COOH
2. (a) Fractional distillation separates the mixture of hydrocarbons in petroleum, collecting the fractions used in
gasoline. Cracking converts larger straight-chain hydrocarbons into the shorter branched-chain hydrocarbons
that are valuable in gasoline.
(b) Three other useful fuels are jet fuel, kerosene, and diesel oil.
3. C, B, D, A. The reason for this order is that more polar compounds have higher boiling points as a result of increased
intermolecular forces. C is an alkane and is nonpolar. B is more polar than C because of its carbonyl group. D is
more polar than B because of its –OH group, which is capable of hydrogen bonding. A is more polar than D because
it has an –OH group and a carbonyl group.
4. (a) acetone (propanone)
(b) acetic acid (ethanoic acid)
(c) formaldehyde (methanal)
HCHO
(d) glycerol (1,2,3-propantriol)
(e) diethyl ether (ethoxyethane)
CH3CH2—O—CH2CH3
5. (a) ethanol, 1-pentanol: Both molecules have a polar hydroxyl group, but the longer hydrocarbon chain in the
pentanol increases its intermolecular van der Waals attractions.
(b) ethoxyethane, propanone: The carbonyl group in the ketone makes it more polar. Therefore, it has stronger
intermolecular attractions.
(c) ethanal, ethanoic acid: The acid has an additional hydroxyl group that the aldehyde does not have, making it
more polar and capable of hydrogen bonding; thus, the acid has stronger intermolecular attractions.
6. (a) propane, 1-propanol: Propane does not contain any polar groups and is therefore insoluble in water. Propanol
contains a hydroxyl group, which allows hydrogen bonding and solubility in water.
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Unit 3 Review Student Book Solutions
163
(b) Methyl ethanoate, ethanoic acid: The ester is less soluble in water than is the carboxylic acid because the acid
has a carbonyl group and a hydroxyl group capable of hydrogen bonding with water, but in the ester, the
hydroxyl group is lost in the ester linkage; thus, the acid is more soluble in water.
(c) 2-butanone, 2-butanol: The ketone has a carbonyl group, but the alcohol has a hydroxyl group that can hydrogen
bond with water. Therefore, 2-butanol is more soluble in water.
7. (a) 2-butanol:
(b) ethoxyethane: CH3CH2OCH2CH3
(c) 2-butanone:
(d) ethanoic acid:
(e) methyl methanoate:
8. The solid formed is the ester. The ester has a lower melting point and solubility in aqueous solvents because it lacks
the hydroxyl group present in both alcohols and carboxylic acids, and thus does not hydrogen bond.
9. (a) triple bond in carbon chain: alkyne
(b) –OH (hydroxyl) group: alcohol
(c) –COOH (carboxyl) group: carboxylic acid
(d) terminal C=O (carbonyl) group: aldehyde
(e) oxygen bonded to two carbon atoms: ether
(f) –NH2 group: amine
(g) C=O (carbonyl) group bonded to two carbon atoms: ketone
(h) COO group: ester
(i) C=O (carbonyl) group bonded to N atom: amide
(j) C=O (carbonyl) group bonded to two carbon atoms: ketone
(k) –COOH (carboxyl) group: carboxylic acid
(l) double bond in carbon chain: alkene
(m) oxygen bonded to two carbon atoms: ether
(n) –OH (hydroxyl) group: alcohol
(o) triple bond in carbon chain: alkyne
(p) COO group: ester
(q) terminal C=O (carbonyl) group: aldehyde
(r) C=O (carbonyl) group bonded to two carbon atoms: ketone
(s) –NH2 group: amine
(t) –OH (hydroxyl) groups: alcohol
(u) C=O (carbonyl) group bonded to N atom: amide
(v) double bonds in carbon chain: alkene
10. (a)
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Unit 3 Student Book Solutions
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(b)
(c)
(d)
(e)
11. (a)
(b)
(c)
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Unit 3 Review Student Book Solutions
165
(d)
12. (a) CH3CH2OH + 3 O2 → 2 CO2 + 3 H2O
H2SO4
(b) CH2=CHCH2CH3 + H2O → CH3CH(OH)CH2CH3
(c) CH3COOH + HN(CH2CH2CH3)2 → CH3CON(CH2CH2CH3)2 + H2O
13. (a) Intermolecular bonding restores the polymer strands to their original position, after any stretching or other
deformation, which makes the polymer elastic.
(b) For intermolecular bonding to occur, a monomer must be able to form bonds other than the bonds forming the
polymer chain itself; that is, it must have an additional functional group (e.g., double bond, hydroxyl group,
carboxyl group), other than the two involved in the polymer linkages, to link with another polymer chain.
Applying Inquiry Skills
14. The three alcohols have different boiling points that increase in the following order: methanol, ethanol, and
1-pentanol. The alcohols can be separated by fractional distillation, using common laboratory equipment. Each
alcohol is collected at its boiling point and condensed. All three alcohols have hydroxyl groups capable of hydrogen
bonding. The larger alcohols have longer nonpolar hydrocarbon chains that increase the van der Waals attractions
between them.
15. Carefully read and follow the recommendations on the MSDS for every chemical substance that you use.
Be aware of the flammability and combustibility of solvents.
Use organic solvents in a well-ventilated location or in a fume hood, away from ignition sources such as electrical
sparks, open flames, and hot surfaces.
Do not store organic solvents in direct sunlight or near heat sources.
Do not use or store organic solvents in basements. Return unused solvents immediately to the appropriate storage
containers.
Organic solvents may be toxic; never eat or drink in the vicinity of organic solvents and always wash your hands
after use.
Dispose of waste solvents according to environmental restrictions. Never pour them down the sink.
16. Looking at states of matter: the alcohol is more likely to be a liquid. The short chain carboxylic acid may be a liquid
or a solid, and the long chain carboxylic acid is more likely a solid. The reason for this conclusion is that alcohols
have hydroxyl groups that allow hydrogen bonding. The carboxyl groups have a carbonyl group in addition to a
hydroxyl group, and thus have stronger intermolecular forces, and are more likely to be solids. The long-chain
carboxylic acid also has stronger van der Waals forces and is thus most likely to be a solid.
When testing solubility in polar and nonpolar solvents, the alcohol and the short-chain carboxylic acid will
likely be soluble in a polar solvent such as water because of the presence of hydroxyl groups. The long-chain
carboxylic acid may be more soluble in nonpolar solvents because of the long hydrocarbon chain.
Using the litmus test, the alcohol would not change blue litmus to pink, but the two acids would.
17. (a) ethanol, CH3CH2OH
(b) ethanoic acid (acetic acid), CH3COOH
(c) CH3COOH + CH3CH2OH → CH3COOCH2CH3 + H2O
(d) Esterification reaction (or condensation reaction)
(e) Eye protection, lab apron, test tubes, pipettes, hot water bath (large beaker of hot water), evaporating dish,
sulfuric acid
(f) Working in a fume hood, place a small volume of the ethanoic acid in a test tube, with a few drops of
concentrated sulfuric acid as a catalyst. Add a small volume of ethanol to the contents of the test tube. Heat the
test tube and contents in the hot water bath for a few minutes. Pour the contents of the test tube into some cold
water in an evaporating dish.
(g) Wear eye protection and a lab apron. Wear gloves when handling concentrated sulfuric acid. Work in a fume
hood or a well-ventilated area. Keep the ethanol away from open flames, electric sparks, and hot surfaces.
Immediately return unused materials to the proper storage containers. Waft when smelling the ester produced.
Dispose of waste solvents in proper containers.
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Unit 3 Student Book Solutions
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18. (Model-building exercise)
19. (a) The borax forms crosslinks between the molecules of glue, changing the glue from a thick liquid to a soft solid.
(b) Make several batches of slime using the same ingredients, but make each batch with a different quantity of
borax. Decreasing or increasing the amount of borax added would probably decrease or increase the elasticity of
the slime because the number of crosslinks formed would change.
Making Connections
20. (a) methyl chloride: CH3Cl
chlorofluorocarbon (CFCs, Freon) e.g., CF2Cl2
hydrochlorofluorocarbons (HCFCs) e.g., CHFCl2
hydrofluorocarbons (HFCs) e.g., CH2F2
(b) These molecules all contain carbon and some combination of hydrogen, chlorine, or fluorine. They were all
considered unreactive and safe to use and to discharge into the environment.
(c) Methyl chloride is toxic. Leakage of the coolant resulted in several deaths. Freon appears to damage the upper
ozone layer, causing ozone “holes” that leave us unprotected from harmful UV radiation. HCFCs and HFCs
cause less damage to the ozone layer, but HFCs release carbon dioxide, a major greenhouse gas.
(d) In the presence of UV light, Freon decomposes, releasing highly reactive chlorine atoms. The chlorine destroys
the ozone molecules in the stratosphere. HCFCs and HFCs readily decompose in the atmosphere and have less
time to cause damage to the ozone layer. HCFCs still contain chlorine, but HFCs contain no chlorine and are the
preferred substitute for CFCs.
21. (a) glucose
glycerol
ethylene glycol
rubbing alcohol (2-propanol)
(b) In order of increasing melting points and boiling points: rubbing alcohol, ethylene glycol, glycerol, glucose. The
reason for this order is the increasing number of hydroxyl groups (1, 2, 3, 6, respectively), which increase the
number of hydrogen bonds formed, thus increasing the amount of energy required to separate the molecules to
melt or to boil.
(c) All four substances should be soluble in water because of the number of polar hydroxyl groups that can
hydrogen bond with water. All four substances are probably not soluble in a nonpolar solvent, such as gasoline,
because they do not contain long nonpolar hydrocarbon chains.
(d) Ethylene glycol is highly toxic and has a sweet taste. Animals or young children may taste ethylene glycol spills
and drink it because of its sweetness.
(e) These four compounds seem to have increasing sweet taste as the number of hydroxyl groups per molecule
increases. This trend may support the hypothesis that taste receptors respond to functional groupsin this case,
the hydroxyl groups.
22. (a) CH3COOH + CH3CH2CH2CH2CH2OH → CH3COOCH2CH2CH2CH2CH3
(b) Student answers will vary, but should refer to the raw materials and the method of synthesis.
(c) The most commonly used natural source of vanilla flavouring is the vanillin plant, Vanilla planifolia, a member
of the orchid family. Vanillin, a glucoside, is extracted from ripe vanillin beans, using ethanol and water, under
cool temperatures to reduce flavour loss. The extract is then aged from a few days to several years.
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Synthetic vanilla flavouring contains a blend of natural vanilla and synthetic chemicals, and cannot be
legally labelled “natural.” The first synthetic vanilla was made from coniferin, and later from euganol, found in
cloves. More recently, synthetic vanilla is made from ethyl vanillin (made from coal tar), or lignin vanillin, a
byproduct of the paper industry. In the 1930s, the Ontario Paper Company solved an environmental problem by
turning their industrial waste, a sulfite liquor, into synthetic vanilla.
23.
Advantages: is relatively easy to make; has not been shown to cause cancer; is 200 times sweeter than sugar.
Disadvantages: has a shelf life of about six months, after which it loses its sweetness; breaks down at high
temperatures, so it cannot be used in baking
Advantages: is easy to make; is stable when heated; is approximately 300 times sweeter than sugar
Disadvantages: may cause cancer in rats (Some studies show that saccharin increases bladder cancer, while other
studies show that there is no correlation between the amount of saccharin and the rate of cancer in rats.)
Advantages: is stable at high temperatures; has a very long shelf life (about 3–4 years); has not been shown to cause
cancer
Disadvantages: none known
24. Desired properties of polymers for use in the dental industry include high tensile strength, durability, insolubility in
water, non-toxicity, resistance to softening at high temperatures (e.g., hot drinks).
• Dental polymers have three main components: a polymer matrix; fillers of various types, sizes, shapes; and a
phase that bonds the other two phases. Shrinkage of the polymer is a common shortfall.
• Monomers may form branched or linear polymer chains. The linear polymer chains can have a parallel alignment
and form crosslinks between chains, which allows for a crystalline structure that produces more of the desired
properties. Dental monomers form strong hydrogen bonds, influencing the polymerization process and the
network structure formed.
• The polymerization process is usually initiated by chemical reduction–oxidation reactions, or by photochemical
redox reactions. Dental fillings are generally cured using a curing lamp, a process that results in 2–3% shrinkage,
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which leads to eventual detachment of the filling from the cavity. Pulse lasers can cause numerous initiations of
the polymerization at the onset of curing, and may reduce the shrinkage of the fillings.
25. [Sample answers] paper (natural, polymer); plastic pen (synthetic, polymer); cotton and polyester shirt (natural and
synthetic, polymer); running shoes (synthetic, polymer); ketchup (natural, polymer); vinegar (natural, not polymer);
butter (natural, not polymer); gasoline (natural, not polymer); television set (synthetic, not polymer); CDs (synthetic,
polymer)
26. Students might give any three of the following:
Synthetic polymer
Use
Monomer
Type of reaction
polyethene
sheet plastic, garbage
bags
ethane
addition reaction
polypropene
rope
propene
addition reaction
polystyrene
foam cups
styrene
addition reaction
nylon
fabrics
dicarboxylic acids and
diamines
condensation reaction
Dacron
fabrics
dicarboxylic acids and
diamines
condensation reaction
27. Student answer will vary. Here are some sample points in a report on gasohol.
Ethanol and gasoline blends provide environmental benefits:
• Ethanol is clean burning, with lower carbon monoxide emissions than regular gasoline.
• Ethanol is low in reactivity and high in oxygen content, making it an effective tool in reducing ozone pollution.
• Ethanol provides a safe replacement for toxic octane enhancers in gasoline such as benzene, toluene, and xylene.
• Ethanol has a nonpolar carbon chain, making it a good solvent for the nonpolar hydrocarbons in gasoline;
however, the polar hydroxyl group renders it soluble in water, so dissolved water droplets may form ice at low
temperatures, blocking gasoline flow.
Extension
28. The solubility of organic halides in water is related to the length of the nonpolar hydrocarbon portion of the alkyl
group. If the alkyl group is small, the halide may be water-soluble and thus can be excreted by an organism as waste.
If the alkyl group is large, the molecule may be insoluble in polar solvents such as water, and soluble in nonpolar
solvents such as the fat tissue in the organism. In this case, the organic halide is not excreted and is stored in the
body. When organisms higher in the food chain eat a number of the affected organisms, the stored organic halides
accumulate to high concentrations in the consumer, reaching toxic levels.
29. (a)
(b) PABA is benzoic acid with an added NH2 group, in position 4; thus, it has an additional polar group that is
capable of hydrogen bonding. Prediction: PABA is a solid at room temperature, with a boiling point higher than
that of benzoic acid. The presence of the carboxyl group and the amino group makes the molecule highly polar
and capable of hydrogen bonding, so PABA might be soluble in water. The presence of the benzene ring
probably makes it soluble in nonpolar solvents such as alcohol and ether. With the presence of both a carboxyl
group and an amino group, PABA can undergo condensation reactions with other molecules, or undergo
condensation polymerization with other PABA molecules.
(c) [Sample answer] Sunscreens provide physical barriers to UV light (zinc oxide and titanium dioxide
compounds), or chemical barriers. PABA is a chemical sunscreen that absorbs radiation in wavelengths that are
invisible to the human eye. PABA is not soluble in water and therefore must be dissolved in alcohol for use;
however, most of the PABA derivatives are water soluble. Sunlight consists of UVA rays (that penetrate deep
into the base layer of skin) and UVB rays (burning rays). Both types of UV rays contribute to skin burning and
skin cancer. PABA provides mostly UVB coverage between 260 and 330 nm. Consumers should select a
sunscreen that screens out both UVA and UVB rays—the “broad spectrum” sunscreens.
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There are some hazards to using PABA. Although sunscreens should be used every day to prevent
premature aging and skin cancer (80% of the Sun’s ultraviolet rays pass through the clouds on a cloudy day),
sun exposure is needed for vitamin D. Thus, regular users of sunscreen may require vitamin D supplements. The
original PABA was sometimes unpopular because it stained clothing. PABA esters, such as glycerol PABA,
pentyl dimethyl PABA, and octyl dimethyl PABA, are now used. Some people are sensitive to PABA and its
esters and should use other sunscreens.
30. The surfactant in bubble bath is usually sodium lauryl sulfate (or, in more expensive or milder brands, sodium
laureth sulfate or sodium lauryl sulfoacetate). Castile soap (made from olive oil) can also be used. To help the
surfactant to form bubbles, glycerine (or sometimes coconut or olive oil) is added. The surfactant (“surface active
agent”) reduces the surface tension of water by interacting with the water molecules. With less surface tension,
bubbles of air in the water remain trapped just below the surface. The addition of glycerine or oil helps the foam to
last longer by slowing down the rate at which the bubbles’ water “skin” evaporates.
31. (a) Starch is the main method of energy storage for plants, as seeds or in tubers. Starches are polymers of glucose,
joined in branched or unbranched chains. These chains have a helical structure, and are sufficiently small to be
soluble in water, which makes the molecules mobile and transportable to different parts of the plant, an
important property for an energy source.
(b) Glycogen is a starch-like molecule produced by animals. It is stored in the muscles as a ready source of energy,
and also in the liver, where it helps to regulate the blood glucose level. Like starch, glycogen has a helical
structure, which makes it soluble in water and readily transportable to different parts of the animal for energy.
(c) Cellulose is made in plants and provides structure and support. In cellulose, the glucose monomers are joined to
form linear chains that align side by side, favouring hydrogen bonding between neighbouring polymer chains.
These interlinked chains produce a rigid structure of layered sheets, giving cellulose its exceptional strength,
and making it insoluble in water.
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