Chapter 9 REVIEW
Part 1
(Pages 406–407)
1. C
2. D
3. A
4. 1, 4, 5, 8
5. 3, 6, 9
6. 1, 4, 5, 7
7. B
8. D
9. A
10. C
11. A
12. B
13. C
14. C
15. A & C
Part 2
(Pages 407–409)
16. (a) 5-methylhept-3-ene
(b) 1,2-diethylcyclopentane
(c) 1-ethyl-2-methylbenzene
17. (a) ethylene
(b) propylene
(c) acetylene
(d) toluene
(e) xylene
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18. Carbon is one of the few elements that can form four covalent bonds and long chains. The
ability to form four bonds allows for a great variety in the way carbon atoms bond with
themselves and with other elements. Carbon atoms also have the ability to easily form almost
any combination of single, double, and triple covalent bonds (that add up to four).
19. Carbon monoxide and carbon dioxide are not considered organic compounds, despite
containing carbon. Both compounds are oxides of carbon. Other compounds containing
carbon that are not considered “organic” include:
Ɣ carbonates like calcium carbonate, CaCO3
Ɣ cyanides like sodium cyanide, NaCN
Ɣ carbides like calcium carbide, CaC2
Ɣ acetates like sodium acetate, NaC2H3O2
These compounds are ionic compounds of carbon-based ions.
20. Alkane family: methane, CH4. Natural gas, an important home heating fuel, is made up of
mainly methane.
Alkene family: ethene, C2H4. Ethene is an important starting material for the production of
plastics such as polyethylene.
Alkyne family: ethyne, C2H2. Ethyne (acetylene) is a fuel used for welding.
Aromatic family: benzene, C6H6. Benzene is commonly used as a solvent for adhesives.
21. The molecular formula of a hydrocarbon can, in most cases, be used to determine the family
to which the compound belongs. All alkanes, for example, have the general formula CnH2n+2.
All alkynes have the general formula CnH2n-2. However, both cycloalkanes and alkenes have
the general formula CnH2n.
22. Distillation and solvent extraction are both physical means of separating components in a
hydrocarbon mixture. Distillation separates components of a mixture on the basis of
differences in boiling points. Solvent extraction separates mixture components by utilizing
differences in solubility in a given solvent. During distillation, the components in a mixture
first vaporize and then condense. During solvent extraction, the desired components are first
selectively dissolved in a solvent and then separated from the solvent.
23. (a)
(b)
(c)
(d)
(e)
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337
(f)
(g)
(h)
(i)
(j)
24. (a)
(b)
(c)
(d)
(e)
(f)
(g)
(h)
(i)
(j)
25.
alkane, saturated
cycloalkane, saturated
alkyne, unsaturated
aromatic, saturated
alkane, saturated
alkane, saturated
alkene, unsaturated
aromatic, saturated
alkene, unsaturated
alkyne, unsaturated
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26. (a)
(b)
(c)
(d)
27. (a) cracking
(b) addition (hydrogenation)
(c) cracking
(d) complete combustion
(e) alkylation
(f) catalytic reforming
(g) thermal or catalytic cracking
28. (a)
(b)
(c)
(d)
(e)
29. (a)
(b)
(c)
(d)
methylbutane
pentane
2-methylpentane
dimethylpropane
2,3-dimethylbutane
pent-1-yne
pent-2-ene
3-methylbut-1-yne
2-methylbut-2-ene
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(e)
(f)
30. (a)
(b)
1-ethyl-2-methylbenzene
3-methylcyclohexane
C9H6O(s) + 10 O2(g) o 9 CO2(g) + 3 H2O(g)
C100H40O10N2S (s) + 108 O2(g) o 100 CO2(g) + 20 H2O(g) + 2 NO2(g) + SO2(g)
31. Problem
What are the boiling points of hexane, hex-1-ene, and hex-1-yne?
Prediction
According to the graphs, the boiling points are predicted, by extrapolation, to be:
hexane, 78 qC; hex-1-ene, 74 qC; and hex-1-yne, 83 qC.
Analysis
According to the CRC Handbook of Chemistry and Physics, the experimental boiling points
are:
hexane, 69 qC; hex-1-ene, 63.5 qC; hex-1-yne, 71.3 qC.
Evaluation
The predictions are judged to be acceptable because the differences are relatively small and
could be accounted for by inherent errors in the extrapolation.
32. Table 2: Some Important Hydrocarbons
IUPAC Name
propyne
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Condensed structural formula
Family/Class
alkynes
Common use
cutting/welding torch
ethene
alkenes
petrochemical feedstock
propene
alkenes
making plastics
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IUPAC Name
methylpropane
Condensed structural formula
Family/Class
alkanes
Common use
butane lighters
2,3,3trimethylpentane
heptane
alkanes
gasoline
alkanes
early anesthetic
methylbenzene
aromatics
solvent
33.
Compound
(a) methane
natural gas
Technological
applications
home heating fuel
(b) ethene
natural gas
and crude oil
feedstock for the
plastics industry
(c)ethyne
natural gas
and crude oil
crude oil
welding
gasoline
crude oil
solvent
(d) 2,2,4trimethylpentane
(e) 1,2dimethylbenzene
Structural formula
Origin
34.
[Several cyclo compounds are also possible: cyclopentane, methylcyclobutane,
1,1-dimethylcyclopropane, and 1,2-dimethylcyclopropane.]
35. (a) 2-methylbutane
(b) 4-methylcyclopentene
(c) but-1-ene
(d) 1,4-dimethylbenzene
(e) 2,2,3-trimethylpentane
(f) 1,4-dimethylcyclohexane
36. Purpose
The purpose of this investigation is to use the properties of organic and inorganic chemicals
to identify unknown chemicals.
Problem
Which of the chemicals provided is organic and which is inorganic?
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Design
Four different substances are heated in a flame to detect evidence of combustion. Organic
substances are more likely to burn than inorganic substances.
Materials
Ɣ eye protection
Ɣ sodium hydrogen carbonate, NaHCO3(s)
Ɣ sucrose (table sugar), C12H22O11(s)
Ɣ calcium carbonate, CaCO3(s)
Ɣ ethanol, C2H5OH(l)
Ɣ metal teaspoon
Ɣ barbecue lighter
Procedure
1. Place a pea-sized sample of sodium hydrogen carbonate in a metal spoon.
2. Heat the sample directly with the flame from the barbecue lighter for two seconds.
3. Examine the surface of the solid for evidence of combustion.
4. Wash the solid/residue off the spoon.
5. Repeat steps 1-4 for each of the other solids.
6. Pour half a teaspoon of ethanol into the spoon.
7. Bring a lit barbecue lighter to within 2 cm of the surface of the ethanol.
8. If the ethanol ignites, allow it to completely burn off.
37. (a) Naphtha is used because its molecules are nonpolar, like the majority of molecules in bitumen.
(b) Toluene is an effective solvent for the asphaltenes because it is a nonpolar aromatic
compound, like the asphaltenes.
(c) Water does not dissolve bitumen because water is polar and bitumen components are
nonpolar. Although water does not dissolve the sand, it does wet the sand and help
separate it from the bitumen. During separation, air is blown into the water and bitumen
mixture. The resulting bitumen froth then rises and floats on the water. This allows the
bitumen to be skimmed from the surface.
38.
Ɣ Fractionation is the physical separation of crude oil into fractions on the basis of
differences in boiling points. (Crude oil is first vaporized.) Substances with the
lowest boiling points travel higher in the distillation column before condensing.
Ɣ Solvent extraction involves adding a liquid to dissolve and remove an impurity or to
separate some useful products.
Ɣ Cracking (including thermal cracking, catalytic cracking, and hydrocracking), breaks
large hydrocarbons into smaller ones. This process helps to increase the yield of the
fractions that are in greatest demand (e.g., gasoline).
cracking example: C17H36(l) o C9H20(l) + C7H16(l) + C(s)
hydrocracking example: C17H36(l) + H2(g) o C9H20(l) + C8H18(l)
Ɣ Catalytic reforming converts aliphatic molecules to aromatics that have superior
combustion properties.
example: heptane o methylbenzene + hydrogen
Ɣ Alkylation converts straight-chain hydrocarbons into branched isomers. Branched
hydrocarbons in gasoline are desirable because they have superior combustion
properties.
example: heptane o 2,4-methylpentane
Impact of Crude Oil Refining
Ɣ Economic: Crude oil refining produces many jobs in the processing and secondary
industries. This creates wealth for workers and the provincial government.
Ɣ Ecological: Crude oil refining has a significant negative impact on the environment,
including plants, animals, and fresh water.
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Technological: Continuous improvements in refining processes produce better yields and
fewer detrimental effects.
Ɣ Social: We should not continue to obtain and process the maximum quantity of oil and
deprive future generations of this valuable resource.
39. Anadarko claims that the lands where it intends to drill for natural gas lie outside Kehewin
Cree reservation lands. Kehewin Cree band members, however, claim that gas exploration in
the area could ruin traditional aboriginal hunting grounds. However, other band members
view the current boom in oil development as a source of much-needed employment for band
members where unemployment rates are unacceptably high.
Some environmentalists are concerned that an environmentally negative resolution of the
dispute between Anadarko and the Kehewin Cree could have a negative impact on similar
negotiations across the province.
Ɣ
Extension
40. (a)
Component
methane
Mole
ratio
(%)
94.9
ethane
2.5
propane
0.2
butane
0.06
Total (natural
gas)
0.9766
Balanced reaction equation
CH4(g) + 2 O2(g) o
CO2(g) + 2 H2O(g)
C2H6(g) + 7/2 O2(g) o
2 CO2(g) + 3 H2O(g)
C3H8(g) + 5 O2(g) o
3 CO2(g) + 4 H2O(g)
C4H10(g) + 13/2 O2(g) o
4 CO2(g) + 5 H2O(g)
Chemical amount of reactants and
products per mole of natural gas
H (mol)
O
CO2
H2O
(mol)
(mol) (mol)
0.949
1.898
0.949 1.898
0.025
0.0875
0.05
0.075
0.002
0.01
0.006
0.008
0.0006
0.00039
0.0024 0.003
0.9766
1.9994
1.0074 1.984
Overall reaction equation for combustion of natural gas:
0.949 CH4(g) + 0.025 C2H6(g) + 0.002 C3H8(g) + 0.0006 C4H10(g) + 1.9994 O2(g) o
1.0074 CO2(g) + 1.984 H2O(g)
(b) First, impurities such as hydrogen sulfide gas must be removed from natural gas due to
environmental concerns. Other components of natural gas are being separated because
they have important applications that are more economically valuable than burning them.
Ethane, for example, is an important feedstock for the production of ethene, used in the
plastics industry. Propane and butane are used as portable fuels in barbecues and cigarette
lighters, respectively.
(c) Exporters of liquid natural gas (LNG) insist that natural gas not be fractionated so that it
can arrive at its final destination with the same chemical composition and properties as
those that it began with. Value-added processing is then done at its destination, bringing
jobs to that area. (In this case this means that Alberta loses jobs and facilities.)
(d) The second largest component of natural gas is ethane. Initially, ethane was not removed
from natural gas because it was costly to establish a condensation process to separate
ethane and the other heavier hydrocarbons from methane in natural gas.
41. It is estimated that over one quarter of the world’s soil carbon is trapped under the ice and
permafrost of northern ecosystems. As the global climate warms and thaws the Arctic
permafrost, the potential for the release of trapped carbon in the form of carbon dioxide and
methane increases. Increased levels of CO2 and CH4 (two important GHGs) would then create
a feedback loop, resulting in further thawing of the permafrost.
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Methane gas is released as a result of the anaerobic decomposition of organic matter.
Anaerobic decomposition occurs where there is a lack of oxygen, such as in the watersaturated soils of thawing permafrost or lake sediments. Greenhouse gases vary in their
ability to trap heat radiated off the surface of the Earth. Methane is a particularly notorious
GHG because it can absorb 21 times more heat than carbon dioxide can. Consequently, any
process that could potentially release large volumes of methane is a concern. Over the past
two centuries, methane concentrations in the atmosphere have almost tripled from 0.7 to
2.0 parts per million. Thawing permafrost could accelerate this increase to alarming levels.
42. The phrase “proven oil reserves” refers to the amount of oil that is still in the ground that has
a greater than 90% chance of being both technically and commercially producible. On the
basis of the following data, Middle East countries, collectively, have the greatest number of
proven oil reserves. However, it is interesting to note that if the reserves locked up in the oil
sands are included, Canada has the second largest proven reserves in the world. It is no
wonder then that in early 2006, US president George W. Bush announced his intention to rely
more on Canadian oil in the future in an effort to decrease US dependence on oil from
political “hot spots” like the Middle East, Nigeria, and Venezuela.
Table of Proven Oil Reserves, 2005
Rank
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Country
Saudi Arabia
Canada1
Iran
Iraq
Kuwait
United Arab Emirates
Venezuela
Russia
Libya
Nigeria
Proved reserves
(billion barrels)
261.9
178.81
125.8
115.0
101.5
97.8
77.2
60.0
39.0
35.3
1
Includes 174.5 billion barrels of oil sands reserves.
[Source: Oil & Gas Journal, Vol. 102, No. 47 (Dec. 10, 2004). From: U.S. Energy
Information Administration.http://www.eia.doe.gov/emeu/international/contents.html]
Technology and politics can have a great influence on determining oil reserves. As oil
recovery technology improves, for example, what were once considered to be non-viable oil
deposits are now being developed. For example, 25 years ago, oil exploration companies
considered drilling only in shallow coastal waters. Today, with recent advances in oil rig
technology and detection methods, exploratory drilling in deeper water is possible. The
technology used to determine oil reserves varies significantly throughout the world. Political
instability in regions such as Nigeria discourages foreign investment, which in turn
discourages the use of state-of-the-art oil exploration technologies. Consequently, any
statement of proven reserves from these regions may not be accurate.
Closer to home, technological advances in the processing of the oil sands over the
past 20 years have significantly reduced the cost of production per barrel of oil.
Geopolitical pressures have a great deal of influence on determining global reserves.
Political instability in many of the important oil-producing regions of the world resulted in a
surge in crude prices during this decade. As oil prices increase, oil deposits that were
considered uneconomical to develop suddenly became viable and were added to the proven
reserves.
43. Some of the other chemical processes that occur during catalytic reforming include:
polymerization, dehydrogenation, and isomerization.
44. (a) The report defines sustainable development as development that “meets the needs of the
present without compromising the ability of future generations to meet their own needs.”
(b) The most prominent perspectives provided are the indigenous (Aboriginal), social, and
ecological perspectives.
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