Kelter P., Mosher M., Scott A. Chemistry. The Practical Science

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528 Chapter 12 Carbon

How do drugs work? Cellular processes, such as intercellular communication,

metabolism (Chapter 14), and construction of the cell structure can be disrupted

by the binding of drug molecules to speciﬁc proteins and other biomolecules

essential to those functions. The organic chemical Taxol™ is arguably one of the

most important anticancer compounds to have been found in a plant extract over

the last 50 years. Let’s brieﬂy trace the discovery of Taxol to show how drug

development occurs in industry.

Taxol

In 1962, National Cancer Institute scientists found that extracts from the bark of

the Paciﬁc yew tree (Taxus brevifolia) had the ability to kill some types of cancer.

Nine years later, the compound responsible for this promising activity,

named paclitaxel or Taxol, was isolated from the yew extract, and its struc-

ture was determined to be the one shown in Figure 12.19. Taxol acts by

tight association with cellular microtubules, which are protein assemblies

essential to cell division. The idea behind using Taxol for anticancer

chemotherapy is to stop the uncontrolled cell division responsible for

tumor growth.

Given Taxol’s importance, scientists needed large quantities of this

compound for experimental treatment of cancer patients and also for basic

research. When large amounts of a natural product are required, chemists can ei-

ther purify it in bulk from its natural source or synthesize it from readily available

materials. In the case of Taxol, neither of these two avenues alone was feasible.

At the time of its discovery, the only known source of Taxol was the bark of

mature Paciﬁc yew trees. Unfortunately, the yield of Taxol obtained from the

Paciﬁc yew is 100 mg per kilogram of bark—a very small amount. Even worse,

bark removal results in the death of the tree. The Paciﬁc yew tree is mainly found

in the Paciﬁc Northwest, and large-scale harvesting of these trees for Taxol would

quickly result in extinction of the tree species. Another way to produce Taxol was

desperately needed.

A potential solution to this problem might have been to synthesize Taxol from

scratch (an approach known as

total synthesis), therefore eliminating the threat

to the Paciﬁc yew tree. The problem is that the structure of Taxol is enormously

complex (compare the structure in Figure 12.19 to the structures of the heptane

isomers from Practice 12.1). What was needed was the development of an efﬁ-

cient total synthesis of Taxol, and synthetic organic chemists accepted the chal-

lenge. After several years of effort, total syntheses of Taxol were accomplished. Yet

even though this was a great feat for modern organic chemistry, these total syn-

theses did little to address the supply problem. All of these total syntheses were

long, technically complex, very costly, and consequently incapable of cheaply

producing large quantities of Taxol. In summary, neither isolation from the

Paciﬁc yew tree nor total synthesis was an environmentally or economically

viable method for the mass production of Taxol.

During the course of Taxol research, chemists found that a biosynthetic

intermediate of Taxol (10-deacetylbaccatin III, shown in Figure 12.20) could be

isolated from the needles of a relative of the Paciﬁc yew tree, in yields of up to 1 g

per kilogram of needles. The tree ﬁrst synthesizes the biosynthetic intermediate

10-deacetylbaccatin III and then converts it to Taxol. And crucially, harvesting

these needles for 10-deacetylbaccatin III is not fatal to the tree. Chemists could

then take advantage of this renewable resource for 10-deacetylbaccatin III by

ﬁnding a way to convert it into Taxol. This is one reason why the efforts to achieve

total synthesis were so important to Taxol production. All of the previous

total syntheses combined the “core”with the “side chain” to give the full structure

of Taxol. Pharmaceutical scientists adopted this same strategy by converting

10-deacetylbaccatin III into something synthetically useful and then attaching

FIGURE 12.19

The chemical structure of Taxol. Can you

identify each of the 11 chiral centers?

FIGURE 12.20

The structure of 10-deacetylbaccatin III.

12.15 Organic Chemistry and Modern Drug Discovery 529

10-Deacetylbaccatin III

Side chain

Core

FIGURE 12.21

The semisynthesis of Taxol.

the “side chain,” as shown in Figure 12.21. This method is called a semisynthetic

method: A portion of the structure of the desired natural product is isolated

from a natural source and then converted into the natural product via synthetic

chemistry.

In 1992, Taxol was approved for use in the United States to treat ovarian can-

cer, breast cancer, and certain types of lung cancer. Along with the drug cisplatin

(see Chapter 20), Taxol is often the ﬁrst drug used in chemotherapy against can-

cer. Today, the pharmaceutical industry uses a version of the semisynthetic

method to produce Taxol.

EXERCISE 12.8 Taxol as a Drug

One problem often associated with drugs is side effects. This problem can come

from a lack of complete speciﬁcity for the target. In treating cancer, we would like to

kill the cancer cells but leave the patients’ normal cells alone. Cancer tissue grows

very rapidly, but other than that, these cells don’t have many other unusual features

compared to normal cells. This is one of the reasons why cancer is such a difﬁcult

disease to treat. Why might Taxol have side effects?

First Thoughts

Cancer cells have acquired mutations in their genetic code that enable them to grow

uncontrollably. Despite this, all of the normal cellular machinery is still present in

cancer cells. First consider the mode of action of Taxol and then think about how

this might affect normal cells.

Solution

Taxol acts by binding to microtubules, which are proteins directly involved in cell

division. When Taxol binds to the microtubules, the cancer cells cannot divide to

give two daughter cells. This can stop the growth of tumors, which are masses of

cells that divide uncontrollably. Because it is nearly impossible to administer Taxol

so that only cancer cells in the patient’s body receive it, the drug is likely to interact

with normal cells as well and bind to their microtubules. As a result, these normal

cells cannot divide, which could result in the disruption of otherwise healthy tissue.

Further Insights

Taxol has revolutionized cancer chemotherapy, but it does have a few major prob-

lems. The ﬁrst was mentioned before: It is in very short supply. Another problem is

its poor formulation properties. Taxol is not very soluble in water, so it is difﬁcult to

administer effectively to patients. In addition, some cancers eventually develop drug

OH O

FIGURE 12.22

The chemical structure of epothilone B.

530 Chapter 12 Carbon

resistance to Taxol. These cancer cells have developed proteins that dispose of Taxol

by shooting it back out from inside the cell, where it can do no good for the patient.

Fairly recently, another class of compounds called the epothilones (one is shown

in Figure 12.22) has been discovered. The epothilones are also effective against can-

cer cells, and they have the same mode of action as Taxol. Unlike Taxol, however,

epothilones are made by a bacterium that is easy to culture on a very large scale.

Therefore, there is no serious supply problem for epothilone. The structure of the

epothilones is simpler than that of Taxol, so organic chemists can more easily make

changes to improve the properties of the drug. Finally, the epothilones are more

water soluble than Taxol and also are effective against Taxol-resistant cancer cell

lines. All of these characteristics have made the epothilones very important com-

pounds in contemporary cancer research.

PRACTICE 12.8

m-Amsacrine is another anticancer drug that exhibits biological activity by binding

to DNA inside cancer cells. Once bound, it causes proteins to break the DNA mole-

cule into fragments. The result is the death of the cancer cell. Would you predict

m-amsacrine to show side effects?

See Problems 97 and 98.

EXERCISE 12.9 Functional Groups of Taxol

Taxol is a very complicated molecule, and organic chemists typically cope with

structural complexity by ﬁrst looking at its most important features: the functional

groups. Look at the structure of Taxol in Figure 12.19, and point out all of the

functional groups you have learned about in this chapter.

Solution

PRACTICE 12.9

What are the functional groups in epothilone B (see Figure 12.22)?

See Problems 51–54.

Ester

Alkene

Ketone

Secondary

alcohol

Secondary

alcohol

Tertiary

alcohol

Ether

Ester

mide

Key Words 531

The Bottom Line

■

Organic chemistry is the study of carbon-containing

compounds, particularly those derived from living

things or fossil fuels. (Section opener)

■

The element carbon occurs in the form of three

allotropes: the diamond, graphite, and fullerene

forms. (Section 12.1)

■

Crude oil is our major source of carbon-containing

compounds, which are processed by the chemical

industry into a wide range of products. (Sec-

tion 12.2)

■

Hydrocarbons are compounds composed of carbon

and hydrogen only. They include the alkanes,

alkenes, alkynes, and aromatic hydrocarbons. (Sec-

tion 12.3)

■

Organic compounds can exist as structural and

geometric isomers. (Section 12.3)

■

Hydrocarbons are separated into fractions by frac-

tional distillation of crude oil. (Section 12.4)

■

Cracking and reforming are two important meth-

ods of preparing speciﬁc organic molecules. (Sec-

tion 12.5)

■

Alkanes can undergo substitution and dehydro-

genation reactions. (Section 12.6)

■

All organic compounds can be regarded as carrying

zero, one, or more distinctive functional groups on

a hydrocarbon frame. (Section 12.7)

■

Each functional group is associated with a distinc-

tive set of chemical characteristics. (Section 12.7)

■

Many modern materials are polymers composed

of thousands of organic monomer units linked

together. (Section 12.8)

■

Molecules may exhibit chirality, which may lead to

different chemical properties in two stereoisomers.

(Section 12.14)

■

Organic chemists can isolate and purify the active

constituents of complex mixtures in order to make

products such as pharmaceuticals. (Section 12.15)

Key Words

achiral A term used to describe molecules that have a

superimposable mirror image. (p. 5

25)

addition reaction A type of reaction in which atoms are

added to a double or triple bond. (p. 514)

addition polymer A polymer formed by the process of

addition polymerization. (p. 515)

addition polymerization A type of polymerization involv-

ing addition reactions among the monomers

involved. (p. 515)

alcohol A chemical containing the hydroxyl (—OH)

group. (p. 514)

aldehydes Compounds that carry a carbonyl functional

group (CPO) with at least one H atom bonded to

the carbonyl carbon atom. (p. 517)

aliphatic compounds Compounds in which all of the

carbon atoms are sp

hybridized and contain only

single bonds. (p. 496)

alkanes Saturated hydrocarbons. (p. 496)

alkenes Hydrocarbons containing at least one CPC

double bond. (p. 500)

alkyl group A hydrocarbon group, such as —CH

—C

, within the structure of an organic com-

pound. (p. 504)

alkyl halide A functional group in which a halogen

atom is bonded to an alkyl group. (p. 511)

alkoxy anion An anion that contains an alkyl group

attached to an oxygen anion, such as CH

−

.(p. 520)

alkynes Hydrocarbons containing a CqC bond.

(p. 501)

allotropes Different forms of the same element.

(p. 493)

amide bond A bond formed by a condensation reaction

between an amino group (—NH

) and a carboxylic

acid group (—COOH). (p. 523)

amine A compound containing the —NH

functional

group. (p. 523)

amino functional group A functional group containing

an —NH

attached to an sp

hybridized carbon

atom. (p. 523)

aromatic hydrocarbons Hydrocarbons that contain one

or more aromatic rings. (p. 504)

carbonyl functional group A functional group containing

the group CPO attached to either hydrogen atoms

(as in the aldehydes) or carbon atoms (as in the

ketones). (p. 517)

carboxyl functional group The —COOH functional

group. (p. 519)

carboxylate anion An anion resulting from the removal

of a hydrogen ion from the oxygen in a carboxylic

acid functional group. (p. 520)

carboxylic acids Organic acids that carry the carboxyl

functional group (—COOH). (p. 519)

catalytic cracking A type of cracking wherein heat and

a catalyst are used. (p. 508)

chiral A term used to denote molecules that have a

nonsuperimposable mirror image. (p. 525)

chiral center A carbon attached to four different

groups. (p. 525)

chirality The quality of being chiral—that is, of having

a nonsuperimposable mirror image. (p. 525)

cis A molecule containing groups that are ﬁxed on the

same side of a bond that cannot rotate. (p. 503)

condensation polymerization Formation of a polymer by

condensation reactions. (p. 522)

condensation reaction A reaction in which two mole-

cules become joined in a process accompanied by

the elimination of a small molecule such as water or

HCl. (p. 520)

cracking The breaking up of hydrocarbons into smaller

hydrocarbons, using heat and in some cases steam

and/or catalysts. (p. 508)

cyclic alkanes Alkanes that possess a group of carbon

atoms joined in a ring. (p. 500)

dehydrogenation The removal of hydrogen. (p. 510)

epoxide A compound containing a triangular ring of

two carbon atoms linked by an oxygen atom, known

as the epoxide group. (p. 524)

epoxy resins Polymer resins containing the epoxide

group, in which two carbons atoms and an oxygen

atom form a cyclic ether ring. (p. 524)

esteriﬁcation The process by which an ester is formed

when the —OH group of an alcohol participates in

a condensation reaction with the —COOH group of

a carboxylic acid. (p. 522)

esters Compounds formed when an alcohol and a car-

boxylic acid become bonded as a result of a conden-

sation reaction. (p. 520)

ether Any compound containing the ether functional

group (—C—O—C—). (p. 524)

fermentation The biological process that converts glu-

cose into ethanol and carbon dioxide. (p. 516)

free radicals Chemical species that carry an unpaired

electron and so are highly reactive. (p. 510)

fullerenes Forms of carbon based on the structure of

buckminsterfullerene, C

.(p. 494)

functional groups Groups of atoms, or arrangements of

bonds, that bestow a speciﬁc set of chemical and

physical properties on any compound that contains

them. (p. 511)

gas chromatography (gc) Analytical technique in which

components of a mixture are separated by their dif-

ferent ﬂow rates through a chromatography column,

driven by a carrier gas. (p. 507)

gas–liquid chromatography (glc) A form of gas chro-

matography in which the solid phase is covered with

a thin coating of liquid. (p. 507)

geometric isomers Molecules that differ in their geome-

try but have identical chemical formula and points

of attachment. See also cis and trans.(p. 502)

high-density polyethylene (HDPE) A form of polyethylene

in which the molecules are linear, with no branch

points. (p. 515)

homologous series A series of compounds sharing the

same general formula. (p. 497)

hydrocarbons Compounds composed of only hydrogen

atoms and carbon atoms. (p. 494)

hydrocracking A type of cracking that uses heat plus a

catalyst in the presence of hydrogen gas. (p. 508)

hydrogenation The addition of a molecule of hydrogen

to a compound. (p. 501)

hydroxyl group The —OH functional group. (p. 514)

ketones Compounds that have two carbon atoms

bonded to a carbonyl carbon atom. (p. 519)

knocking The rapid explosion of a gas–air mixture as it

is compressed in an automobile cylinder before the

spark plug creates the spark that is intended to cause

the mixture to explode. (p. 509)

low-density polyethylene (LDPE) A form of polyethylene

with branched-chain molecules that are shorter than

the unbranched chains found in HDPE. (p. 515)

methylene group The —CH

— group. (p. 497)

monomer One of the small chemical units that com-

bine with other monomers to form polymers.

(p. 515)

normal alkanes Alkanes that have no branched chains

or rings of carbon atoms. (p. 496)

octane rating A number assigned to motor fuel (gas)

on the basis of its “anti-knock” properties. (p. 509)

organic chemistry The chemistry of carbon-containing

compounds, especially those derived from living

things or fossil fuels. (p. 492)

organic compound Carbon-based compounds. (p. 492)

polyamides Polymers whose monomers are bonded

together by amide bonds. (p. 523)

polyesters Polymers in which the monomers are held

together by repeated ester linkages. (p. 522)

polyethenes Organic polymers made when huge num-

bers of ethene molecules participate in addition reac-

tions with themselves to generate long chain-like

molecules. Also known as polyethylenes. (p. 574)

polyethylenes See polyethenes. (p. 515)

polymer A chemical composed of large molecules

made by the repeated bonding together of smaller

monomer molecules. (p. 515)

primary alcohols Alcohols that have no more than one

carbon atom bonded to the carbon atom that car-

ries the hydroxyl group. (p. 517)

532 Chapter 12 Carbon

reforming A process that changes a mixture of pre-

dominantly straight-chain hydrocarbons into a mix-

ture containing more aromatic and branched-chain

hydrocarbons. (p. 508)

saturated hydrocarbons Hydrocarbons that do not con-

tain double or triple bonds. (p. 496)

secondary alcohols Alcohols that have two carbon

atoms bonded to the carbon atom that carries the

hydroxyl group. (p. 517)

steam cracking A form of cracking in which heat,

steam, and a catalyst are used. (p. 508)

stereoisomers Structural isomers that differ in their

three-dimensional arrangements of atoms, rather

than in the order in which the atoms are bonded.

(p. 525)

straight-chain alkanes Molecules that contain only

hydrogen atoms and sp

hybridized carbon atoms

arranged in linear fashion. (p. 497)

structural isomers Molecules with the same formula but

different structures. (p. 498)

substitution reactions Reactions in which one or more

atoms (often hydrogen atoms) are replaced by other

types of atoms (often halogens or a hydroxyl

group). (p. 510)

tertiary alcohols Alcohols that have three carbon atoms

bonded to the carbon atom that carries the hydroxyl

group. (p. 517)

thermal cracking A form of cracking that uses heat

alone. (p. 508)

total synthesis the preparation of a molecule from

readily available starting materials. Typically the

total synthesis involves many steps. (p. 528)

trans A molecule containing groups that are ﬁxed

on opposite sides of a bond that cannot rotate.

(p. 503)

unsaturated hydrocarbons Hydrocarbons that contain

CPC or CqC bonds. (p. 501)

Focus Your Learning 533

Focus Your Learning

The answers to the odd-numbered problems and some selected

problems appear at the back of the book, as represented by the

blue numbering.

12.1 Elemental Carbon

Skill Review

1. List the three allotropes for carbon, and indicate the

hybridization of the carbon atoms in each.

2. Explain the differences in the properties of amorphous

(lacking a deﬁned crystalline shape, disordered) carbon and

graphite.

Chemical Applications and Practices

3. Carbon in the diamond form and carbon in the graphite

form have widely differing uses. We pay hundreds, even

thousands, of dollars for diamond jewelry, but only pennies

for carbon in pencils. Explain, using the differences in bond-

ing, why diamonds are held together more strongly than the

carbon atoms in graphite.

4. Using hybridization, explain how carbon forms both sigma

and pi bonds in graphite, but only sigma bonds in the dia-

mond form.

5. Diamonds are typically measured in carats (1 carat is 200 mg).

If an industrial diamond contained only carbon, how many

atoms of carbon would be found in a 2.00-carat diamond?

6. Graphite can be converted to diamond with great pressure.

The type of diamond used in polishing powder can be pro-

duced with pressures on the order of 1000 MPa.

a. What is this pressure in terms of atmospheres?

b. Why is pressure a factor in conversion of the graphite form

of carbon to the diamond form?

12.2 Crude Oil—the Basic Resource

Skill Review

7. Judging on the basis of Table 12.2, what is the main difference

between the aliphatic and the aromatic compounds found in

crude oil?

8. Judging on the basis of Table 12.2, what is the difference

between the structures and formulas for compounds in the

aliphatic and naphthene classes?

Chemical Applications and Practices

9. Sulfurous compounds occur to a minor extent in crude oil,

and their presence is indicative of the source of the crude.

Explain how the decomposition of biological material could

give rise to sulfur-containing compounds.

10. Why do you think that there is such a wide diversity of com-

pounds in crude oil?

12.3 Hydrocarbons

Skill Review

11. Provide the correct name for each of these:

a. CH

(CH

)

CH(CH

)

c. CH

CH(CH

)

b. CH

CH(CH

)

d. CH

12. Provide the correct name for each of these:

a. CH

CH(CH

)

c. CH

C(CH

)

b. CH

d. (CH

)

CHCH

CH(CH

)

13. Diagram the structure of the compounds listed in Prob-

lem 11.

14. Diagram the structure of the compounds listed in Prob-

lem 12.

15. Complete this table:

16. Complete this table:

17. a. Diagram the structure of each of these:

pentane

2-methylbutane

2,2-dimethylpropane

Also give the empirical formula of each.

b. Remembering that intermolecular forces affect boiling

point, match each structure with its corresponding boil-

ing point (all are in degrees Celsius): 9.5, 36, 28.

18. a. Diagram the structure of each of these:

3-ethyl-2-pentene

cyclooctene

3-hexyne

Also give the molecular formula of each.

b. Remembering that intermolecular forces affect boiling

point, match each structure with its corresponding boil-

ing point (all are in degrees Celsius): 82, 94, 148.

19. One of the high-molecular-mass hydrocarbons that helps

form the protective waxy skin of an apple contains 28 carbon

atoms. What is the formula of this noncyclic alkane?

20. What is the formula of a saturated noncyclic hydrocarbon

containing 8 carbons? Assume that a different hydrocarbon

contains two CPC groups and has a total of 10 carbon

atoms. What is its formula?

21. Diagram ﬁve isomers of octane that all have a six-member

continuous carbon chain.

22. Diagram three isomers of octane that all have a ﬁve-member

continuous carbon chain.

23. Which, if any, of these hydrocarbons could be cycloalkanes?

a. C

c. C

b. C

d. C

24. How many hydrogen atoms are found in one molecule of

cyclodecane?

25. Identify each of these molecules as a cis or a trans isomer.

26. Identify each of these molecules as a cis or a trans isomer.

Chemical Applications and Practices

27. Ethyne (also known as acetylene) can be produced by the

reaction between calcium carbide (CaC

) and water. In ad-

dition to ethyne, calcium hydroxide is a product. Write and

balance the equation for the production of this important

alkyne.

28. The combustion of methane is an important reaction that

heats our homes. Incomplete combustion, however, involves

the reaction of methane with oxygen to produce carbon

monoxide and water. Write and balance the equation for the

incomplete combustion of methane.

29. Cyclohexane and benzene both have a ring structure

containing six carbon atoms. Compare the two structures in

terms of:

a. The number of hydrogen atoms in each

b. Carbon orbital hybridization

c. The angles between carbon atoms

d. The number of double bonds

e. Resonance structures

30. Four alkene isomers that contain two CPC can be drawn for

. Draw these four isomers and identify the one that is

stabilized most by resonance structures.

12.4 Separating the Hydrocarbons

by Fractional Distillation

Skill Review

31. Mixtures of hydrocarbons, and of other types of compounds,

can be separated into their individual components by gas

chromatography. Brieﬂy explain the main steps by which this

technique makes possible the identiﬁcation of compounds in

a mixture.

32. For speciﬁc uses, hydrocarbon fractions obtained from crude

oil may be further modiﬁed. The two major industrial

processes that provide useful hydrocarbon products are

cracking and reforming. Compare and contrast these two

important techniques.

33. What property of hydrocarbons serves as the basis for a sep-

aration, during fractional distillation, of the components in

crude oil? What is the relationship between this property and

the structure of the components?

CCH

534 Chapter 12 Carbon

Alkane Alkene Alkyne

Type of C to C

bond

Type of

hybridization

Alkane Alkene Alkyne

Angles between

bonds to other

atoms

If made of only

two carbons, will

have __ total

hydrogen atoms

Saturated or

unsaturated?

34. Although gas chromatography is often used to resolve mix-

tures of hydrocarbons, it cannot be relied on in every case.

What is a chief limitation of GC when applied to hydro-

carbon separations?

12.5 Processing Hydrocarbons

Skill Review

35. The octane rating system has been used as a standard to rate

the burning efﬁciency of other fuels. What is the formula of

octane? Use the formula to write and balance the reaction for

the combustion of octane.

36. The actual isomer of octane used in the rating system is

“isooctane.” The descriptive name for the compound is 2,2,4-

trimethypentane. Diagram the structure of this compound

and write a balanced reaction for the combustion of isooctane.

Chemical Applications and Practices

37. Another compound, besides isooctane, used in fuel studies

was found to have the following percentage composition:

84.0% carbon and 16.0% hydrogen. The molar mass of the

alkane is 100.0. From these data, what would you calculate as

the molecular formula of the compound?

38. Calculate the mass percent carbon and the mass percent

hydrogen of isooctane.

39. Currently, many automobiles run on fuel with a minimum

octane rating of 87. To what mixture of isooctane and hep-

tane does this fuel correspond?

40. Some additives to gasoline have a much higher octane rating.

For instance, a particular alcohol has an octane rating of 116.

What quantity of this alcohol would need to be added to

crude gasoline (octane rating 55) to give a product with an

octane rating of 92?

12.6 Typical Reactions of the Alkanes

Skill Review

41. Using methane and bromine, show the balanced equation to

form dibromomethane.

42. Using butane as a reactant, show the balanced equation that

produces 2-butene.

43. Provide the structural diagram and the name for all of the

products that would result from the substitution reaction

between Cl

and ethane.

44. Provide the structural diagram and the name for all of the

products that would result from the dehydrogenation of

butane.

45. What are the typical products that result from the combus-

tion of an alkane?

46. A reaction produces a molecule with a CPC bond. If the

product was made from an alkane, what would be the classi-

ﬁcation of this reaction?

Chemical Applications and Practices

47. The combustion of propane to form carbon dioxide and

water can produce approximately 2200 kJ per mole. If a

burning propane torch used 42.0 g of propane, how many

kilojoules would be released?

48. Why do arctic hikers use propane as fuel for their cook stoves

instead of pentane?

12.7 The Functional Group Concept

Skill Review

49. Provide a suitable chemical formula and an example struc-

ture of a molecule for each of these functional groups.

a. alcohol b. aldehyde c. alkene d. ketone

50. Provide a suitable chemical formula and an example struc-

ture of a molecule for each of these functional groups.

a. carboxylic acid b. alkyne c. ether d. cyclic alkane

Chemical Applications and Practices

51. The structure of the common analgesic acetaminophen fol-

lows. Identify any and all functional groups shown in the

structure.

52. The structure for tetracycline follows. Identify any and all

functional groups shown in the structure.

53. The partially complete structure (showing all atoms except

hydrogen) for the pesticide malathion follows. Reproduce

the structure and add the missing hydrogen atoms to the

molecule.

54. The partially complete structure (showing only carbons and

oxygens) for carvone follows. Reproduce the structure

and add the missing hydrogen atoms to the molecule.

O C C

C O C C

OH O O

CCH

Focus Your Learning 535

12.8 Ethene, the CPC Bond, and Polymers

Skill Review

55. How many carbon–carbon π bonds are present in each of

these noncyclic molecules?

a. C

b. C

c. C

56. How many carbon–carbon π bonds are present in each of

these noncyclic molecules?

a. C

b. C

c. C

57. Diagram the structure of each of these compounds:

a. 3-Methyl-2-pentene

b. 2-Methyl-4-propyl-3-heptene

58. Name these compounds:

Chemical Applications and Practices

59. One gram of an important hydrocarbon, when completely

combusted, produced 2.93 g of carbon dioxide and 1.80 g of

water. The molar mass of the compound is 30.0. Is this com-

pound an alkane or an alkene? What is the formula of the

compound?

60. Chemists often refer to the addition reaction of alkenes as

“adding across the double bond.” Explain what aspect of the

double bond between carbon atoms favors this process.

61. a. Diagram the structure of propene.

b. Show the balanced equation that represents the conversion

of propene into the alcohol 1-propanol.

62. One way to distinguish an alkane from an alkene is to halo-

genate the double bond. If propene reacted with Br

, what

compound would be formed?

63. Polypropylene is an addition polymer with many uses, one of

which is in indoor–outdoor carpeting.

a. What is the structure of the monomer used in this polymer?

b. Diagram a section of polypropylene using four joined

monomers.

64. Clothing materials made from Orlon

contain the addition

polymer polyacrylonitrile shown here.

After examining the structure, diagram the structure of the

repeating monomer.

H C

N N

CH CH CH CH

65. HDPE and LDPE are both plastics that can be recycled.

HDPE is coded as 2, and LDPE is coded as 4. What contrast-

ing structural factor in the molecules of these two polymers

causes their differing properties?

66. Indicate which of these statements is(are) true? For those

that are false, explain why.

a. Addition reactions always involve compounds with

multiple bonds.

b. All addition reactions produce polymers, but not all

polymers are addition polymers.

c. All addition polymers are based on reactions between

molecules with multiple bonds.

d. Addition polymers must contain double bonds.

12.9 Alcohols

Skill Review

67. After looking at the structure of a compound, a student in-

correctly named it 2,5-pentanediol. Provide the correct name

for the compound.

68. Another compound was mislabeled as 1,4-propanediol.

Explain the mistake in this name.

69. Diagram the structure of 1,3-pentanediol. Classify each

—OH group as primary, secondary, or tertiary.

70. Diagram the structure of 2-butanol. Would this alcohol be

classiﬁed as a primary, secondary, or tertiary alcohol?

Chemical Applications and Practices

71. Phenol is an example of an aromatic alcohol containing six

carbons, six hydrogens, and one oxygen. It is used in produc-

ing disinfectants and some polymers. Diagram the structure

of this important compound.

72. Alcohols can undergo a reaction known as dehydration. In

this reaction, the alcohol loses a molecule of water to form

an alkene. Provide the name of the alkene formed from the

dehydration of each of these alcohols:

a. Ethanol

b. 1-Propanol

c. 2-Propanol

d. 1-Butanol

12.10 From Alcohols to Aldehydes, Ketones,

and Carboxylic Acids

Skill Review

73. Draw the structure of 1-propanol, and identify the product

that would result from oxidation of this compound.

74. Diagram the structure of butanal. What alcohol can be oxi-

dized to produce this compound?

75. Propanoic acid is used to make a type of mold inhibitor. Di-

agram the structure of propanoic acid. What aldehyde could

be oxidized to form this acid?

76. Isopropyl alcohol (2-propanol) is used as the ingredient in

rubbing alcohol. This compound can be oxidized to a ketone,

but not to a carboxylic acid. Draw the structure of the alcohol

and the ketone, and explain why it can’t be used to produce

the corresponding three-carbon carboxylic acid.

536 Chapter 12 Carbon

Chemical Applications and Practices

77. Methyl ethyl ketone is often used as a solvent for organic

compounds. Diagram the structure of this important organic

compound. What secondary alcohol could be oxidized to

form this compound?

78. An unknown compound was oxidized to form pentanoic

acid. The unknown compound was either 2-pentanone or

pentanal. Identify the starting compound.

79. Carboxylic acids are generally considered only weakly acidic.

Show the acid dissociation reaction of propanoic acid in

water.

80. An unknown compound was found to produce an acidic

solution and contained four carbon atoms. The compound

could be prepared from a straight-chain alcohol. Identify the

unknown compound and the starting alcohol.

12.11 From Alcohols and Carboxylic Acids to Esters

Skill Review

81. The ester that produces a banana aroma is called 3-methyl-

butyl ethanoate. Diagram the structures of the starting mate-

rials that produce the ester, and show the balanced equation

for the production of isopentyl acetate.

82. An apple-like aroma can be produced from the combination

of methanol and butanoic acid. Diagram the structure and

name this ester.

83. An apricot aroma can be produced from the ester pentyl bu-

tanoate. Using structures, show the balanced equation that

produces this pleasant fruity aroma.

84. Tristearin is the animal fat associated with beef. The formula

of stearic acid is CH

(CH

)

COOH. Show the reaction be-

tween stearic acid and 1,2,3-propanetriol to form the triple

ester known as tristearin.

Chemical Applications and Practices

85. Linoleic acid is used to form the major oil found in corn. This

unsaturated acid has two double bonds per molecule. The

double bonds are found between carbon atoms number 9

and 10 and between carbon atoms number 12 and 13. The

formula is C

. Draw the diagram of this linear unsat-

urated carboxylic acid.

86. Oleic acid (a major component of animal fats) contains a cis

alkene and 18 carbon atoms and has the formula C

The alkene is found between carbons number 9 and 10. Draw

the diagram of this linear carboxylic acid.

12.12 Condensation Polymers

Skill Review

87. The simplest amino acid is glycine. Use the structure shown

below to diagram a condensation polymer made from three

glycine monomers. What molecule has been split out as the

polymer forms?

88. Why is the formation of a condensation polymer impossible

in these cases?

a. Ethanoic acid + NH

b. Ethanoic acid + CH

c. HOOC-CH

-COOH + CH

Chemical Applications and Practices

89. Thiokol, dating back to the 1920s, was the ﬁrst synthetic

rubber commercially produced in the United States. It can

be formed as a condensation polymer from the monomer

ClCH

OCH

Cl. The reaction takes place when

sodium polysulﬁde (Na

) reacts with the monomer. Assum-

ing that Na

is a source of —S—S—, draw the structure of

the polymer. What smaller compound is also produced from

the reaction?

90. In addition to water, a by-product from the condensation

polymerization of 5-aminopentanoic acid is common. What

is the structure of this by-product?

COOH (5-aminopentanoic acid)

12.13 Polyethers

Skill Review

91. Using the information and examples in the chapter, devise

the name of these ethers.

92. Using the information and examples in the chapter, draw the

structure for these ethers.

a. ethyl methyl ether

b. propyl methyl ether

c. butyl ethyl ether

12.14 Handedness in Molecules

Skill Review

93. Indicate whether chirality exists in each of these objects.

a. a pencil c. your textbook

b. your feet d. a fork

94. Indicate whether chirality exists in each of these objects.

a. a CD c. a bottle

b. a butterﬂy d. a sportscar

95. Identify the chiral center in each of these molecules.

96. Identify the chiral center in each of these molecules.

H H

O CH

Focus Your Learning 537