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You may not see it, but carbonis everywhere. It is in yourclothes, your backpack, your
books, and your food. It is even inyou. Carbon is an amazing element.In this chapter, you will learn howcarbon can form more than 16 millionknown compounds. Also, you will seehow black, gooey petroleum is trans-formed into useful substances. Youwill be introduced to some carboncompounds essential to life itself—among them proteins and DNA.
What do you think? Science Journal Look at the picturebelow with a classmate. Discuss whatthis might be. Here’s a hint: This pat-tern offers an infinite variety of forms.Write your answer or best guess inyour Science Journal.
Organic Compounds2121
639
The element carbon exists in three very differentforms. It exists as dull, black charcoal; slippery,
gray graphite; and bright, sparkling diamond. How-ever, this is nothing compared with the millions of different compounds that carbon can form. In thisactivity, you will seek out the carbon hidden in twocommon substances.
WARNING: Always use extreme caution around an open flame. Point test tubes away from yourself and others.
Identify a common element
1. Place a small piece of bread in a test tube.
2. Using a test-tube holder, hold the tube over the flame of a laboratory burner until you observe changes in the bread.
3. Using a clean test tube and a small amount of paper instead of bread, repeat step 2.
Observe 1. What happened when you heated the tubes? Did you see anything leave
the two samples?
2. What remained in each of the test tubes? Describe it in your ScienceJournal. What do you think it is?
EXPLOREACTIVITY
Making a Vocabulary Study Fold Make thefollowing vocabulary Foldable to ensure youhave understood the content by defining the
vocabulary terms from this chapter.
1. Place a sheet of notebook paper in front of you so the short side is at the top. Fold the paper in half from the left side to the right side.
2. Through the top thickness of paper, cut along every third line fromthe outside edge to the centerfold, forming ten tabs, as shown.
3. On the front of each tab, write a vocabulary word listed on the firstpage of each section in this chapter. On the back of each tab, definethe word.
FOLDABLESReading & StudySkills
FOLDABLESReading &Study Skills
Organic Compounds What do you have in common with your athletic shoes, sun-
glasses, and backpack? All the items shown in Figure 1 containcompounds of the element carbon—and so do you. Most com-pounds containing the element carbon are organic compounds.
At one time, scientists thought that only living organismscould make organic compounds, which is how they got theirname. Did you notice the similarity between the terms organicand organism? By 1830, scientists could make organic com-pounds in laboratories, but they continued to call them organic.
Of the millions of carbon compounds known today, morethan 90 percent of them are considered organic. The other tenpercent, including carbon dioxide and the carbonates, areconsidered inorganic compounds because they are found innonliving things, such as air, rocks, and minerals.
Bonding You may wonder why carbon can form so manyorganic compounds. The main reason is that a carbon atom has four electrons in its outer energy level. This means that eachcarbon atom can form four covalent bonds with atoms ofcarbon or with other elements. As you have learned, a covalentbond is formed when two atoms share a pair of electrons. Fouris a large number of bonds compared to the number of bonds
that atoms of other elements can form.This allows carbon to form manytypes of compounds ranging fromsmall compounds used as fuel, tocomplex compounds found in medi-cines and dyes, and the polymers usedin plastics and textile fibers.
640 CHAPTER 21 Organic Compounds
Simple Organic Compounds
S E C T I O N
� Identify the difference betweenorganic and inorganic carbon compounds.
� Examine the structures of someorganic compounds.
� Differentiate between saturatedand unsaturated hydrocarbons.
� Identify isomers of organic compounds.
Vocabularyorganic compoundhydrocarbonsaturated hydrocarbonisomerunsaturated hydrocarbon
Carbon compounds surround you—they’re in your food, your body, andmost materials you use every day.
Figure 1 Most items used every daycontain carbon.
Arrangement Another reason carbon can form so manycompounds is that carbon can link together with other carbonatoms in many different arrangements—chains, branchedchains, and even rings. It also can form double and triple bondsas well as single bonds. In addition, carbon can bond with atomsof many other elements, such as hydrogen and oxygen. Figure 2shows some possible arrangements for carbon compounds.
Hydrocarbons Carbon forms an enormous number of compounds with
hydrogen alone. A compound made up of only carbon andhydrogen atoms is called a hydrocarbon. Does the furnace,stove, or water heater in your home burn natural gas? A maincomponent of the natural gas used for these purposes is the hy-drocarbon methane. The chemical formula of methane is CH4.
Methane can be represented in two other ways, as shown inFigure 3A. The structural formula shows that four hydrogenatoms are bonded to one carbon atom in a methane molecule.Each line between atoms represents a single covalent bond. Thespace-filling model in Figure 3A shows a more realistic picture ofthe size and arrangement of the atoms in the molecule.Chemists might refer to space saving models occasionally, butuse chemical and structural formulas to write about reactions.
Another hydrocarbon used as fuel is propane. Some stoves,most outdoor grills, and the heaters in hot-air balloons burn thishydrocarbon, which is found in bottled gas. Propane’s structuralformula and space-filling model are shown in Figure 3B.
Methane and other hydrocarbons produce more than90 percent of the energy humans use. Carbon compounds alsoare important in medicines, foods, and clothing. To understandhow carbon can play so many roles, you must understand how itforms bonds.
SECTION 1 Simple Organic Compounds 641
MethaneCH4
H — C — H
H
H
——
PropaneC3H8
H — C — C — C — H
H
H
——
H
H
——
H
H
——
Figure 3Natural gas is mostly
methane, CH4. Bottled gas ismostly propane, C3H8.
H — C — C — C — C — C — C — C — H
H
——
H
——
H
H
——
H
——
HH
H
——
HH H
H
——
H
H
——
H
H
—
H
C C — C C
H
H
—— ——
H — C — H
H
—H O
OH
O — C — H
H
—
H
—
H
H H
C
C
C
C
C
C
C
——
——
——
—
——
— —
H
H — C — H
——
H
Figure 2 Carbon atoms bond to form
chains, as in heptane found ingasoline. The chains can bebranched, as in isoprene, foundin natural rubber. The chainsalso can be rings, as in vanillin,found in vanilla flavor.
Single Bonds In some hydrocarbons, the carbon atoms
are joined by single covalent bonds. Hydro-carbons containing only single-bonded car-bon atoms are called saturated hydrocarbons.Saturated means that a compound holds asmany hydrogen atoms as possible—it is satu-rated with hydrogen atoms.
What are saturatedhydrocarbons?
Table 1 lists four saturated hydrocarbons.Notice how each carbon atom appears to be alink in a chain connected by single covalentbonds. Figure 4 shows a graph of the boilingpoints of some hydrocarbons. Notice the rela-tionship between boiling points and the addi-tion of carbon atoms.
Structural Isomers Perhaps you have seen or know aboutbutane, which is a gas that sometimes is burned in campingstoves and lighters. The chemical formula of butane is C4H10.Another hydrocarbon called isobutane has exactly the samechemical formula. How can this be? The answer lies in thearrangement of the four carbon atoms. Look at Figure 5. In amolecule of butane, the carbon atoms form a continuous chain.The carbon chain of isobutane is branched. The arrangement ofcarbon atoms in each compound changes the shape of the -molecule. Isobutane and butane are isomers.
642 CHAPTER 21 Organic Compounds
Figure 4 Boiling points of hydrocarbonsincrease as the number of car-bon atoms in the chainincreases.
Number of carbon atoms in chain
Boili
ng p
oint
(°C)
Methane
Ethane
PropaneButane
Pentane
0 1 2 3 4 5 6
50
0
–50
–100
–150
–200
Boiling Points of Hydrocarbons
Table 1 Some Hydrocarbons
Name Chemical Structural Formula Formula
Methane CH4
Ethane C2H6
Propane C3H8
Butane C4H10
H
H — C — H
——
H
H
H — C — C — H
——
H H
H
——
H
H — C — C — C — H
——
H
H—
—H
——
HH
H
H — C — C — C — C — H
——
H
H
——
H
——
HH H
H
——
SECTION 1 Simple Organic Compounds 643
Modeling Structuresof Octane
Procedure1. To model octane, C8H18, a
hydrocarbon found in gaso-line, use soft gumdrops to represent carbon atoms.
2. Use raisins to representhydrogen atoms.
3. Use toothpicks forchemical bonds.WARNING: NEVER eat any
food in the laboratory.
Analysis1. How do you distinguish one
structure from another?2. What was the total number
of different molecules foundin your class?
ButaneC4H10
H — C — C — C — C — H
H
H
——
H
H
——
H
H—
—
H
H
——
Figure 5 Butane has two isomers. One isomerhas a straight chain.
The other isomer has a branched chain.
Table 2 Properties of Butane Isomers
Property Butane Isobutane
Description Colorless gas Colorless gas
Density 0.60 kg/L 0.603 kg/L
Melting Point –135°C –145°C
Boiling Point –0.5°C –10.2°C
Isomers are compounds that have identical chemical formu-las but different molecular structures and shapes. Thousands ofisomers exist among the hydrocarbons. Generally, meltingpoints and boiling points decrease as the amount of branchingin an isomer increases. You can see this pattern in Table 2, whichlists properties of butane and isobutane.
Sometimes properties of isomers can vary amazingly. Forexample, the isomer of octane having all eight carbons in astraight chain melts at �56.8°C, but the most branched octanemelts at 100.7°C. In this case, the high melting point resultsfrom the symmetry of the molecule and its globular shape. Lookfor this isomer when you do the Try at Home MiniLAB.
Other Isomers There are many other kinds of isomers inorganic and inorganic chemistry. Some isomers differ onlyslightly in how their atoms are arranged in space. Such isomersform what is often called right- and left-handed molecules, likemirror images. Two such isomers may have nearly identicalphysical and chemical properties.
IsobutaneC4H10
H — C — C — C — H
H — C — H
H
——
——
H
H
——
H
—
H
H
——
Multiple Bonds Peaches are among the many fruits that can form
small quantities of ethylene gas, which aids in ripen-ing. Ethylene is another name for the hydrocarbonethene, C2H4. This contains one double bond inwhich two carbon atoms share two pairs of electrons.The hydrocarbon ethyne contains a triple bond inwhich three pairs of electrons are shared. Hydrocar-bons, such as ethene and ethyne, that contain at leastone double or triple bond are called unsaturatedhydrocarbons. They are shown in Figure 6.
What is another name forethene?
Remember that saturated hydrocar-bons contain only single bonds andhave as many hydrogen atoms as possi-ble. Hydrocarbons having more thanone double or triple bond are calledpolyunsaturated, because the prefix polymeans many.
644 CHAPTER 21 Organic Compounds
Section Assessment
1. Explain why carbon can form so manyorganic compounds?
2. Compare and contrast ethane, ethene,and ethyne.
3. How is an unsaturated hydrocarbon different from a saturated hydrocarbon?
4. How did organic compounds get this name?
5. Think Critically Cyclopropane is a satu-rated hydrocarbon containing three carbonatoms. In this compound, each carbon atomis bonded to two other carbon atoms. Drawits structural formula. Are cyclopropane andpropane isomers? Explain. Carbon can formsingle, double, and triple bonds easily. Howmany electrons are shared between two car-bon atoms joined in a triple bond?
6. Making and Using Graphs Make a graph ofTable 1. For each compound, plot the numberof carbon atoms on one axis and the number ofhydrogen atoms on the other axis. Use the graphto predict the formula of hexane, which has sixcarbon atoms. For more help, refer to the Sci-ence Skill Handbook.
7. Solving One-Step Equations Compare theformulas of three saturated hydrocarbons: C2H6,C3H8, and C4H10. What mathematical relation-ship do you see between the number of carbonatoms and the number of hydrogen atoms ineach? Compare the number of carbon and thenumber of hydrogen atoms in the unsaturatedhydrocarbons C2H4, C3H6, and C4H8. For morehelp, refer to the Math Skill Handbook.
Figure 6 Hydrocarbons can contain doubleor triple bonds between carbonatoms. Ethyne, also calledacetylene, is used in torches forwelding. Ethene or ethylenegas ripens fruit.
H H
H
C C
H
——
H — C C — H———
SECTION 2 Other Organic Compounds 645
Aromatic Compounds Chewing flavored gum or dissolving a candy mint in your
mouth releases pleasant flavors and aromas. Many chemical com-pounds produce pleasant odors but others have less pleasant fla-vors and smells. For example, aspirin, which has an unpleasant,sour taste, is shown in Figure 7A. The compound that producesthe fresh fragrance of wintergreen is shown in Figure 7B. Both ofthese compounds are considered aromatic compounds. In addi-tion to the fragrances mentioned here, aromatic compoundscontribute to the smell of cloves, cinnamon, anise, and vanilla.
You might assume that aromatic compounds are so namedbecause they are smelly—and most of them are. However, smellis not what makes a compound aromatic in the chemical sense.To a chemist, an aromatic compound is one that contains abenzene structure having a ring with six carbons.
What structure is found in all aromatic compounds?
� Define aromatic compounds.� Identify the nature of alcohols
and acids.� Identify organic compounds
you use in daily life.
Vocabularyaromatic compoundsubstituted hydrocarbonalcohol
Aromatic compounds are buildingblocks of thousands of usefulcompounds, such as flavoringsand medicines.
Other Organic Compounds
S E C T I O N
Figure 7You can see the six-carbonbenzene ring in these aromaticcompounds. Aspirin is acetylsalicylic acid. Wintergreen ismethyl salicylate.
C — OH
O
O — C — CH3
— —
O
— —
C — O — C — H
HO
—
H
—
OH
— —
646 CHAPTER 21 Organic Compounds
Benzene C6H6
NaphthaleneC10H8
Benzene Look at a model of benzene, C6H6, and its structuralformula in Figure 8. As you can see, the benzene molecule has sixcarbon atoms bonded into a ring. The electrons shown as alter-nating double and single bonds that form the ring are shared byall six carbon atoms in the ring. This equal sharing of electronsis represented by the special symbol shown in Figure 8C. Thesharing of these electrons causes the benzene molecule to bevery stable because all six carbon atoms are bound in a rigid, flatstructure. Many compounds contain this stable ring structure.The stable ring acts as a framework upon which new moleculescan be built.
What is responsible for the stability of thebenzene ring?
Fused Rings Moth crystals have a distinct odor. One type ofmoth crystal is made of naphthalene (NAF thuh leen). This is adifferent type of aromatic compound that is made up of tworing structures fused together, as shown in Figure 9. Manyknown compounds contain three or more rings fused together.Tetracycline (te truh SI kleen) antibiotics are based on a fusedring system containing four fused rings.
Substituted Hydrocarbons Usually a cheeseburger is a hamburger covered with melted
American cheese and served on a bun. However, you can make acheeseburger with Swiss cheese and serve it on toast. Such sub-stitutions would affect the taste of this cheeseburger.
In a similar way chemists change hydrocarbons into othercompounds having different physical and chemical properties.They may include a double or triple bond or add different atomsor groups of atoms to compounds. These changed compounds arecalled substituted hydrocarbons.
Figure 9 Naphthalene used in moth crystals is an example of a fused-ring system.
H
H
H
H
H
H
C
C
C
CC
C
— —
——
——
— —
—
Figure 8 Benzene, C6H6, can berepresented by a space-filling model, a structuralformula, or the benzenesymbol.
A substituted hydrocarbon has one or more of its hydrogenatoms replaced by atoms or groups of other elements. Depend-ing on what properties are needed, chemists decide what to add.Examples of substituted hydrocarbons are shown in Figure 10.
Alcohols and Acids Rubbing alcohol gets its name fromthe fact that it was used for rubbing on aching muscles. Rubbingalcohol is a substituted hydrocarbon. Alcohols are an importantgroup of organic compounds. They serve often as solvents anddisinfectants, and more importantly can be used as pieces toassemble larger molecules. An alcohol is formed when –OHgroups replace one or more hydrogen atoms in a hydrocarbon.Figure 10A shows ethanol, an alcohol produced by the fermen-tation of sugar in grains and fruit.
Why are alcohols considered substitutedhydrocarbons?
Organic acids form when a carboxyl group, –COOH, is sub-stituted for one of the hydrogen atoms attached to a carbonatom. Look at Figure 10. The structures of ethane, ethanol, andacetic acid are similar. Do you see that acetic acid, found invinegar, is a substituted hydrocarbon? You know some otherorganic acids, too—citric acid found in citrus fruits, such asoranges and lemons, and lactic acid found in sour milk.
C C
Cl Cl
Cl Cl
——
TetrachloroetheneC2Cl4
H — C — C
H
——
H
Acetic acidCH3COOH
——
O
OH
Carbon compounds alsoare found in space. Aboutfive percent of meteoritescontain water and carboncompounds. Carbon com-pounds, such as formic acidand a form of acetylene,have been detected inouter space using radiotelescopes. The areaswhere they are found arethought to be regions ofspace where new starsare forming.
H — C — C — OH
H
——
H
——
HH
EthanolC2H5OH
Figure 10 Substituted hydrocarbons come in a variety of forms.
Most ethanol, C2H5OH, often called grain alcohol, isobtained from corn. Acetic acid is found in vinegar.
Tetrachloroethene is a compound used in dry cleaning.
SECTION 2 Other Organic Compounds 647
648 CHAPTER 21 Organic Compounds
Section Assessment
1. What do the structures of all aromatic compounds have in common?
2. How is each of the following a substitutedhydrocarbon: tetrachloroethene, ethanol,
and acetic acid?
3. What elements other than oxygen couldbe added to a hydrocarbon to produce asubstituted hydrocarbon?
4. Explain why chemists might want to pre-pare substituted hydrocarbons. Give twoexamples of possible substitutions.
5. Think Critically Chloroethane, C2H5Cl,can be used as a spray-on anesthetic forlocalized injuries. How does chloroethanefit the definition of a substituted hydro-carbon? Diagram its structure.
6. Interpreting Scientific Illustrations Formicacid, HCOOH, is the simplest organic acid. Drawits structural formula by referring to the struc-ture of acetic acid in Figure 10B. For morehelp, refer to the Science Skill Handbook.
7. Communicating Examine the different waysa benzene molecule can be represented, asshown in Figure 8. Do you think the doublebonds in the structural formula shown inFigure 8B must always be written in the posi-tions shown? In your Science Journal, explainyour answer and discuss why benzene can berepresented by a six-sided figure containinga circle. For more help, refer to the ScienceSkill Handbook.
Figure 11Strangely, small concentrationsof foul-smelling compounds areoften found in pleasant-smellingsubstances. For example, themercaptan in skunk spray isamong the 834 components ofcoffee aroma.
Substituting Other Elements Other atoms besideshydrogen and oxygen can be added to hydrocarbons. One ischlorine. When four chlorine atoms replace four hydrogenatoms in ethylene, the result is tetrachloroethene (teh truh kloruh eth EEN), a solvent used in dry cleaning. It is shown inFigure 10C. Adding four fluorine atoms to ethylene makes acompound that can be transformed into a black, shiny materialused for nonstick surfaces in cookware. Among other possiblesubstituted hydrocarbons are molecules containing nitrogen,bromine, and sulfur.
When sulfur replaces oxygen in the –OH group of an alco-hol, the resulting compound is called a thiol, or more common-ly a mercaptan. Most mercaptans have unpleasant odors. Thiscan be useful to animals like the skunk shown in Figure 11.
Mercaptan odors are not only unpleasant, they are alsopowerful. You can smell skunk spray even in concentrations aslow as 0.5 parts per million. Though you might not think so,such a powerful stink can be an asset, and not just for skunks. Infact, smelly mercaptans can save lives. As you know natural gashas no odor of its own so it is impossible to smell a gas leak. Forthis reason, gas companies add small amounts of a bad-smellingmercaptan to the gas to make people aware of any leaks beforegas can accumulate to dangerous levels.
ACTIVITY 649
Design a table and record what changes takeplace in the color of the solution. Compareyour observations with those of other students in your class. For more help, referto the Science Skill Handbook.
Alcohols and Organic Acids
Procedure1. Pour 1 mL of 0.01M potassium perman-
ganate solution and 1 mL of 6M sodiumhydroxide solution into a test tube.
2. Add 3 drops of ethanol to the test tube.
3. Stopper the test tube. Gently shake it for1 minute. Observe and record any changes inthe solution for 5 minutes.
Conclude and Apply1. What is the structural formula for ethanol?
2. What part of a molecule identifies a com-pound as an alcohol?
3. What part of a molecule identifies a com-pound as an organic acid?
4. Explain how you know that a chemicalchange took place in the test tube.
5. In the presence of potassium permanganate,an alcohol may undergo a chemical changeinto an acid. If ethanol is used, predict the formula of the acid produced.
6. The acid from ethanol is found in a commonhousehold product—vinegar. What is theacid’s chemical name?
Have you ever wondered how chemistschange one substance into another? You
have learned that changing the bonding amongatoms holds the key to that process.
What You’ll InvestigateHow can an alcohol change into an acid?
Materialslarge test tube and stopper0.01M potassium permanganate solution (1 mL)6M sodium hydroxide solution (1 mL)ethanol (3 drops)10-mL graduated cylinder
Safety Precautions
Always handle these chemicals with care;immediately flush any spill with water.
Goals� Control the immediate environment of a
reaction to produce a specific compound.
� Gather evidence to form conclusions aboutthe identity of a new compound formed froma chemical reaction.
650 CHAPTER 21 Organic Compounds
Petroleum—A Source of Carbon Compounds
S E C T I O N
What is petroleum?Do you carry a comb in your pocket or purse? What is it
made from? If you answer plastic, you are probably right, but doyou know where that plastic came from? Chances are it camefrom petroleum—a dark, flammable liquid, often called crudeoil, that is found deep within Earth. Like coal and natural gas,this dark, foul-smelling substance is formed from the remains offossilized material. For this reason these substances often arecalled fossil fuels.
How can a thick, dark liquid like petroleum be transformedinto a hard, brightly colored, useful object like a comb? Theanswer lies in the nature of petroleum. Petroleum is a mixture ofthousands of carbon compounds. To make items such as combs,the first step is to extract the crude oil from its undergroundsource, as shown in Figure 12. Then, chemists and engineersseparate it into its individual compounds using a physical prop-erty that you have learned about. This property is the boilingpoint. Even though petroleum contains a large number of com-pounds, each compound has its own boiling point.
Separating Petroleum Com-pounds The separation processis known as fractional distillation.It takes place in petroleum refiner-ies. If you have ever driven past arefinery, you may have seen thesebig, metal towers called fractionat-ing towers. They often rise as highas 35 m and can be 18 m wide andhave pipes and metal scaffoldingattached to the outside.
� Explain how carbon compoundsare obtained from petroleum.
� Compare and contrast differencesamong the various petroleum-based fuels.
� Determine how carbon com-pounds can form long chains.
� Identify some of the ways petro-leum enriches your world.
Vocabularypolymermonomerpolyethylene
Petroleum gives us fuels, plastics,clothing, and many other products.
Figure 12Drilling for petroleum beneath theocean floor requires huge platforms.
Ocean surface
Oil platform
Ocean floor
Oil wells
Natural gas
Rock layers
Oil
The Tower Inside the tower is a series ofmetal plates arranged like the floors of abuilding. These plates have small holes sothat vapors can pass through. On the out-side you can see a maze of pipes at variouslevels. The tower separates crude oil intofractions containing compounds having arange of boiling points. Within a fraction,boiling points may range more than 100°C.
How It Happens The crude petroleumat the base of the tower is heated to morethan 350°C. At this temperature mosthydrocarbons in the mixture becomevapor and start to rise. The higher boilingfractions reach only the lower plates beforethey condense, forming shallow pools thatdrain off through pipes on the sides of thetower and are collected.
Fractions with lower boiling pointsmay climb higher to the middle platesbefore condensing. Finally, those with thelowest boiling points condense on the top-most plates or never condense at all andare collected as gases at the top of thetower. Figure 13 shows some typical frac-tions and how they are used.
Why don’t the condensed liquids fall back through the holes?The reason is that pressure from the rising vapors prevents this.In fact, the separation of the fractions is improved by the inter-action of rising vapors with condensed liquid. The processesinvolved vary. For example, some towers add steam at the bot-tom to aid vaporization. The design and process used depend onthe type of crude oil and on the fractions desired.
Uses for Petroleum Compounds Some fractions are used directly for fuel—the lightest frac-
tions from the top of the tower include butane and propane.The fractions that condense on the upper plates and containfrom five to ten carbons are used for gasoline and solvents.Below these are fractions with 12 to 18 carbons that are used forkerosene and jet fuel. The bottom fractions go into lubricatingoil, and the residue is used for paving asphalt. Figure 14 showsthe variety of useful products that can be obtained from petro-leum, in addition to its use as a fuel.
SECTION 3 Petroleum—A Source of Carbon Compounds 651
40°C – 200°C
Above 300°C
Above 350°C
250°C – 400°C
175°C – 275°C
Gasoline
Kerosene
Jet fuel and diesel oil
Lubricating oil
Asphalt
Hydrocarbon gasesused for fuels and
plastics
Below 20°C
Heatedcrude oil
Figure 13Typical fractions are separated ina fractionating tower by theirboiling points.
Figure 14
PRINTING INKThe ink used innewspapers is madefrom carbon black,another productfrom petroleum.
PLASTICS The durabilityof hard plastic makes itthe ideal material for acell phone keypad.
FUELS This commuter jet is being refueled at an air-port. Most of the world’spetroleum is still used inthe form of fuel.
VISUALIZING PETROLEUMPRODUCTS
652
MEDICINES The activeingredient in aspirinused to be extractedfrom the bark of willow trees. Today it is manufacturedfrom petroleum.
Petroleum, or crude oil, provides the raw materialfor a huge number of products that have becomeessential to modern life. After it has been refined,
petroleum can be used to make various types of fuel,plastics, and synthetic fibers, as well as paint, dyes,and medicines.
FABRICS Like the fleece used to make these gloves, many modern fabrics are made from synthetic, rather than natural,fibers. Some of the most popular syn-thetic fibers—polyester andnylon are petroleum-based.
PolymersDid you ever loop together strips of paper to make paper
chains for decorations, or have you ever strung paper clipstogether? A paper chain can represent the structure of a polymeras shown in Figure 15. Some of the smaller molecules frompetroleum can act like links in a chain. When these links arehooked together, they make new, extremely large moleculesknown as polymers. The small molecule, which forms a link inthe polymer chain, is called a monomer. Mono means one.
How are polymers similar to paper chains orlinked paper clips?
Common Polymers One common polymer or plastic ismade from the monomer ethene or ethylene. Under standardroom-temperature conditions, this small hydrocarbon is a gas.However, when ethylene combines with itself repeatedly, itforms a polymer called polyethylene. Polyethylene (pah lee EHthuh leen) is used widely in shopping bags and plastic bottles.Another common polymer is polypropylene (pah lee PRO puhleen) used to make glues and carpets. Often two or more differ-ent monomers, known as copolymers, combine to make onepolymer molecule.
Polymers can be made light and flexible or so strong thatthey can be used to make plastic pipes, boats, and even someauto bodies. In many cases, they have replaced natural buildingmaterials, such as wood and metal. Because so many things usedtoday are made of synthetic polymers, some people call this “TheAge of Plastics.”
SECTION 3 Petroleum—A Source of Carbon Compounds 653
Figure 15Imagine this paper chain extended by 10,000 units.Thenimagine each link as a monomer. Now you have an ideaof what a typical polymer used to make plastic looks like.
Visualizing Polymers
Procedure1. Use paper clips to represent
monomers in a syntheticpolymer. Hook about 20together to make a chain.
2. Cut 20 strips of coloredpaper and mark each witha different letter of thealphabet from A to T.
3. Assemble these strips inrandom order to make apaper chain.
Analysis1. Imagine both chains
extended to contain 10,000 or more units.Compare them in terms ofease of construction anddegree of complexity.
2. Compare the paper chainsmade by your class. Howmany different combina-tions of letters are there?
654 CHAPTER 21 Organic Compounds
Figure 16Processing can modify a polymer’s properties. Polystyreneused in CD cases is clear, hard, and brittle. Polystyrene usedin cups is opaque, light-weight, and foamy.
Designing Polymers The properties of polymers dependmostly on which monomers are used to make them. Also, likehydrocarbons, polymers can have branches in their chains. Theamount of branching and the shape of the polymer greatlyaffect its properties.
Polymer materials can be shaped in many ways. Some aremolded to make containers or other rigid materials. Sometimesthe same polymer can take two completely different forms. Forexample, polystyrene (pah lee STI reen) that is made fromstyrene, shown in Figure 16, forms brittle, transparent cases forCDs and lightweight, opaque, foam cups and packing materials.To make this transformation, a gas such as carbon dioxide isblown into melted polystyrene as it is molded. Bubbles remainwithin the polymer when it cools, making polystyrene foam anefficient insulator.
Other polymers can be spun into threads, which are used to make clothing or items such as suitcases and backpacks.Fibers can be made strong and durable for products that receivewear and tear. Others can resist strong impacts. For example,bullet-proof vests are made of a tightly woven, synthetic poly-mer. Polymer fibers also can be made stretchy and resilient forfabric products like exercise garments. Some polymers remainrigid when heated, but others become soft and pliable whenheated and harden again when cooled.
Name some applications of polymer fibers.
Research Visit theGlencoe Science Web site atscience.glencoe.com tolearn more about polymers.Communicate to your classwhat you learn.
Other Petroleum Products Other fractions obtained from fractional distilla-
tion of petroleum may be purified further by differ-ent techniques to isolate individual compounds. Afterthese are separated, they can be converted into substi-tuted hydrocarbons, as you learned in the last section.Chemists use these to make products ranging frommedicines such as aspirin to dyes, insecticides,printers’ ink, and flavorings.
Many of the products that come from petroleumare aromatic compounds. For example, the sweetenersaccharin is related to toluene, a substituted benzenemolecule. It has from 200 to 700 times the sweeteningpower of sugar, but no calories. In fact, it passesunchanged through the digestive tract. Althoughother sweeteners are available today, saccharin still is usedwidely in many diet foods and to sweeten mouthwash, as shownin Figure 17.
Also, aromatic dyes have replaced natural dyes, such as indigoand alizarin, almost completely. The first synthetic dye was abright purple called mauve that was discovered accidentally incoal tar compounds. Today, most dyes come from petroleum.
SECTION 3 Petroleum—A Source of Carbon Compounds 655
Section Assessment
1. What is petroleum and where does it come from?
2. Why are some fuels referred to as fossil fuels?
3. Which fractions of petroleum are useddirectly for fuel? How are they obtainedfrom petroleum?
4. What is the name for substances madefrom thousands of small molecules that are linked together? What are the smallmolecules called?
5. Think Critically Petroleum fractionsobtained by fractional distillation containmany individual compounds. How mightthese mixtures be separated further? Whatphysical property could be used?
6. Predicting Based on the names of thepolymers and monomers in this section,what do you think polymers made from themonomers terpene and urethane would becalled? For more help, refer to the ScienceSkill Handbook.
7. Communicating Research at least twosynthetic polymers other than those mentionedin this section. Write in your Science Journalwhich monomers they include, the approximate
length of their chains, and how they are used.
Describe their properties and, if possible, howthey are related to polymer structure. Reportyour findings to your class. For more help, referto the Science Skill Handbook.
Figure 17Saccharin is used as a sweetenerbecause it doesn’t damage teethlike sugar can.
NH
SO2
C
O
— —
Glycine
Cysteine
N — C — C
H
——
H
O
OH
H
H
——
H — C — H
S — H
—
H — N — C — C
—
H
—
H
O
OH
——
H
H — C — H
S — H
—
N C — C
—
H
O � HOH
OH
——
O
N — C — C
H
——
H
H
H
——
656 CHAPTER 21 Organic Compounds
Biological CompoundsS E C T I O N
Biological Polymers Like the polymers that are used to make the plastics and
fibers, biological polymers are huge molecules. Also, they aremade of many smaller monomers that are linked together. Themonomers of biological polymers are usually larger and morecomplex in structure. Still, you can picture a biologicalmonomer as one link in a very long chain.
Many of the important biological compounds in your bodyare polymers. Among them are the proteins, which often con-tain hundreds of units.
ProteinsProteins are large organic polymers formed from organic
monomers called amino acids. Even though only 20 aminoacids are commonly found in nature, they can be arranged inso many ways that millions of different proteins exist. Proteinscome in numerous forms and make up many of the tissues inyour body, such as muscles and tendons, as well as your hairand fingernails. In fact, proteins account for 15 percent of yourtotal body weight.
� Compare and contrast proteins,nucleic acids, carbohydrates,and lipids.
� Identify the structure of polymersfound in basic food groups.
� Identify the structure of large biological polymers.
Vocabularyproteinnucleic aciddeoxyribonucleic acid (DNA)carbohydratelipid
All life processes depend on largebiological compounds.
Figure 18In a protein polymer, peptidebonds link together moleculesof amino acids.
Each amino acidalso contains acarboxylic acid(–COOH) group.
Peptide bondslink moleculesof amino acids.
Water is formedfrom the –OH of acarboxylic groupand the –H of anamine group.
Each amino acidcontains anamine (–NH2)group.
Protein Monomers Amino acids are the monomers that com-bine to form proteins. Two amino acids are shown in Figure 18A.The –NH2 group is the amine group and the –COOH group is thecarboxylic acid group. Both groups appear in every amino acid.
Amine groups of one amino acid can combine with thecarboxylic acid group of another amino acid, linking themtogether to form a compound called a peptide as shown in Figure 18B. The bond joining them is known as a peptide bond.When a peptide contains a large number of amino acids—about50 or more—the molecule is called a protein.
Approximately how many amino acid unitsdoes a protein contain?
Protein Structure Long protein molecules tend to twist andcoil in a manner unique to each protein. For example, hemoglo-bin, which carries oxygen in your blood, has four chains thatcoil around each other as shown in Figure 19. Each chain con-tains an iron atom that carries the oxygen. If you look closely,you can see all four iron atoms in hemoglobin.
When you eat foods that contain proteins, such as meat,dairy products, and some vegetables, your body breaks downthe proteins into their amino acid monomers. Then your bodyuses these amino acids to make new proteins that form muscles,blood, and other body tissues.
SECTION 4 Biological Compounds 657
Figure 19 Four peptide chains coil around eachother in the protein polymer hemo-globin. Each chain has an atom of iron, which carries oxygen.
Iron atomcarrying oxygen
Nucleic AcidsThe nucleic acids are another important group of organic
polymers that are essential for life. They control the activitiesand reproduction of cells. One kind of nucleic acid, calleddeoxyribonucleic (dee AHK sih ri boh noo klay ihk) acid orDNA, is found in the nuclei of cells where it codes and storesgenetic information. This is known as the genetic code.
Nucleic Acid Monomers The monomers that make upDNA are called nucleotides. Nucleotides are complex moleculescontaining an organic base, a sugar, and a phosphoric acid unit.In DNA two nucleotide chains twist around each other formingwhat resembles a twisted ladder or what is called the doublehelix. Human DNA contains only four different organic bases,but they can form millions of combinations. The bases on oneside of the ladder pair with bases on the other side, as shown inFigure 20. The genetic code gives instructions for making othernucleotides and proteins needed by your body.
658 CHAPTER 21 Organic Compounds
What do you like to eat? You probablychoose your foods by how good they
taste. A better way might be to look at theirnutritional value. Your body needs nutrientslike proteins, carbohydrates, and fats to giveit energy and help it build cells. Almostevery food has some of these nutrients in it.The trick is to pick your foods so you don’tget too much of one thing and not enoughof another.
Identifying the ProblemThe table on the right lists some
basic nutrients for a variety of foods. Theamount of the protein, carbohydrate, andfat is recorded as the number of grams in100 g of the food. By examining these data,can you select the foods that best provideeach nutrient?
Selecting a Balanced Diet
Problem-Solving Activity
Food (100 g) Protein (g) Carbohydrate (g) Fat (g)
Cheddar 25 01 33cheese
Hamburger 17 23 17
Soybeans 13 11 07
Wheat 15 68 02
Potato chips 07 53 35
Nutritional Values for Some Common Foods
Solving the Problem 1. Using the table, list the foods that supply
the most protein and carbohydrates.What might be the problem with eatingtoo many potato chips?
2. In countries where meat and dairy prod-ucts are hard to get, people eat a lot offood made from soybeans. Can youthink of reasons why people might wishto substitute meat and dairy productswith soybean based products?
Data Update Visit theGlencoe Science Web site atscience.glencoe.com forrecent news of magazinearticles about DNA finger-printing. Communicate toyour class what you learn.
SECTION 4 Biological Compounds 659
Nucleotides
Base pairs
M613-22C-MSS02DNA double helix structure
DNA Fingerprinting Human DNA contains more than5 billion base pairs. The DNA of each person differs in someway from that of everyone else, except for identical twins, whoshare the same DNA sequence. The unique nature of DNAoffers crime investigators a way to identify criminals from hairor fluids left at a crime scene. DNA from bloodstains or cells insaliva found on a cigarette can be extracted in the laboratory.Then, chemists can break up the DNA into its nucleotide com-ponents and use radioactive and X-ray methods to obtain apicture of the nucleotide pattern. Comparing this pattern toone made from the DNA of a suspect can link that suspect tothe crime scene.
Carbohydrates If you hear the word carbohydrate, you
may think of bread, cookies, or pasta. Haveyou heard of carbohydrate loading by ath-letes? Runners, for example, often preparefor a long-distance race by eating, or load-ing up on, carbohydrates in foods such asvegetables and pasta. Carbohydrates arecompounds containing carbon, hydrogen,and oxygen, that have twice as manyhydrogen atoms as oxygen atoms. Carbo-hydrates include the sugars and starches.
Figure 20DNA models show how nucleotides arearranged in DNA. Each nucleotide lookslike half of a ladder rung with an attachedside piece. As you can see, each pair ofnucleotides forms a rung on the ladder,while the side pieces give the ladder a littletwist that gave DNA the name double helix.
Sugars Sugars are a major group of carbohydrates, as shownin Figure 21. The sugar glucose is found in your blood and alsoin many sweet foods such as grapes and honey. Common tablesugar, known as sucrose, is broken down by digestion into twosimpler sugars—fructose, often called fruit sugar, and glucose.Unlike starches, sugars provide quick energy soon after eating.
Starches Starch, shown in Figure 22, is a carbohydrate that isalso a polymer. It is made of units or monomers of the sugarglucose. During digestion, the starch is broken down intosmaller molecules of glucose and other similar sugars, whichrelease energy in your body cells.
Athletes, especially long-distance runners, use starches toprovide high-energy, long-lasting fuel for the body. The energyfrom starches can be stored in liver and muscle cells in the formof a compound called glycogen. During a long race, this storedenergy is released, giving the athlete a fresh burst of power.
LipidsFats, oils, and related compounds make up a group of
organic compounds known as lipids. Lipids include animal fatssuch as butter, and vegetable oils such as corn oil. Lipids containthe same elements as carbohydrates but in different propor-tions. For example, lipids have fewer oxygen atoms and containcarboxylic acid groups.
How are lipids like carbohydrates? How arethey different?
660 CHAPTER 21 Organic Compounds
H OH
C C
OHC C
Glucose C6H12O6
HO HO
H
—
H
—
— —
Figure 22 Starch is the major componentof pasta.
O
CH2OH
H OH
C C
OH
C O
C C
HH
——
—
H
—
— —
CH2OH
H OH
C C
OH
C O
C C
HHH
——
—
H
—
— —
O
H H
O O
CH2OH
H OH
C C
OH
C O
C C
HHH
——
—
H
—
— —
O
CH2OH
H OH
C C
OH
C O
C C
HHH
——
—
H
—
— —
C
H
C
HOCH2
O
CH2OH
Sucrose C12H22O11
H OH
C C
OH
C O
CH2OH
O
CH
——
—
H
—
HO
—
H
—
—H
C
——
OH
C
—
C CHO
H HC
H
Figure 21 Sucrose and glucose are sugarsfound in foods. Fruits containglucose and another simplesugar called fructose. Why are
sugars carbohydrates?
Fats and Oils These substances are similar in structure tohydrocarbons. They can be classified as saturated or unsaturated,according to the types of bonds in their carbon chains. Saturatedfats contain only single bonds between carbon atoms. Unsatu-rated fats having one double bond are called monounsaturated,and those having two or more double bonds are called polyun-saturated. Animal lipids or fats tend to be saturated and aresolids at room temperature. Plant lipids called oils are unsatu-rated and are usually liquids, as shown in Figure 23. Sometimeshydrogen is added to vegetable oils to form more saturated solidcompounds known as hydrogenated vegetable shortenings.
Have you heard that eating too much fat can be unhealthy?Evidence shows that too much saturated fat and cholesterol inthe diet may contribute to some heart disease and that unsatu-rated fats may help to prevent heart disease. It appears that satu-rated fats are more likely to be converted to substances that canblock the arteries leading to the heart. A balanced diet includessome fats, just as it includes proteins and carbohydrates.
Cholesterol Another lipid that is often in the news is choles-terol, which is found in meats, eggs, butter, cheese, and fish.Even if you never eat foods containing cholesterol, your bodymakes its own. Some cholesterol is needed by the body to buildcell membranes. It is also found in bile, a digestive fluid. Toomuch cholesterol may cause serious damage to heart and bloodvessels, similar to the damage caused by saturated fats.
SECTION 4 Biological Compounds 661
Section Assessment
1. What is a polymer? Why are polymersimportant organic compounds? Give somespecific examples.
2. Compare and contrast proteins and nucleicacids in terms of their structures and theirfunctions in your body.
3. Where does your body get the amino acidsit needs to build proteins?
4. Explain the difference between saturatedand unsaturated fats and oils. Which typeis considered healthier in foods?
5. Think Critically Is ethanol a carbo-hydrate? Explain.
6. Comparing and Contrasting In terms of DNAfingerprinting, compare and contrast identicaltwins and two people who are not identicaltwins. For more help, refer to the ScienceSkill Handbook.
7. Solving One-Step Equations Changing justone amino acid in a chain changes the functionof the entire protein. If the letters G, L, C, and Irepresent four amino acids, how many differentpeptides containing four amino acids can bemade? For more help, refer to the Math Skill Handbook.
Check the label on anyavailable container of milk.What percentage of fat is in the milk? Infer anyadvantages of drinkinglow-fat milk.
Figure 23 At room temperature, fats are normally solids, and oils are usually liquids.
Preparing an Ester
662 CHAPTER 21 Organic Compounds
Goals� Prepare an ester from an alcohol and
an acid.� Detect the results of the reaction by
the odor of the product.
Materialsmedium-size test tubetest-tube holder250-mL beaker10-mL graduated cylinderwaterhot platering stand thermometersalicylic acid (0.2 g)methyl alcohol (2 mL)concentrated sulfuric acid (2 or 3 drops
to be added by teacher)
Safety Precautions
WARNING: Sulfuric acid is caustic.
Avoid all contact. Mix all the contents
together using a glass stirring rod. Do not
use the thermometer as a stirring rod.
Are esters aromatic compounds? Organic compounds known as acids and alcoholsreact to form another type of organic compound called an ester. Esters frequently
produce a recognizable and often pleasant fragrance, even though they are not aro-matic in the chemical sense—they might not contain a benzene ring. Esters areresponsible for many fruit flavors, such as apple, pineapple, pear, and banana.
What You’ll InvestigateHow do an acid and an alcohol combine to produce a compound with different char-acteristics? Can the presence of the new compound formed be detected by its odor?
Conclude and Apply1. What did you smell in step 6?
2. Look closely at the surface of theliquid in the test tube. Do you seeany small droplets of an oily sub-stance? What do you think it is?
ACTIVITY 663
Write a description of your experiment inyour Science Journal. Suggest how you mightmodify the experiment to produce a differentester. For more help, refer to the ScienceSkill Handbook.
Procedure3. Add 2 mL of methyl alcohol to the
test tube. Before adding it, check tosee if this compound has an odor.If so, try to remember what itsmells like.
4. Ask your teacher to add carefullythree to five drops of concentratedsulfuric acid.
5. Place the test tube in the hot waterand leave it untouched for about12 to 15 minutes.
6. Remove the tube from the hotwater using a test-tube holder andallow it to cool. Check to see if youcan detect a new aroma.
WARNING: Any compound you can
smell has entered your body, and
unknown compounds can be toxic or
caustic. To detect an aroma safely, hold
the container about 10 cm in front of your
face and wave your hand over the open-
ing to direct air currents to your nose.
See the illustration below for the properway to detect odors in the laboratory.
1. Add about 150 mL of water to thebeaker and heat it on the hot plateto 70ºC.
2. Place approximately 0.2 g of salicylic acid in a test tube. Doesthis material have an odor?
Waft the vapor towardyour face gently.
O
— —
HO — C — H
H
—
H
—
H
—
H
—
C — OH
O
— —OH
— C — O — C — H ?� �→OH
—
3. Look at the equation for the reactionbelow. One product is given. Whatdo you think is the second productformed in this reaction?
Accidentsin SCIENCE
SOMETIMES GREAT DISCOVERIES HAPPEN BY ACCIDENT!
In 1953, Americanchemist Patsy Sherman invented a
way to protect fabricsfrom accidental spills.Strangely enough, thisdiscovery came aboutbecause of an accidentalspill in her lab.
i l l“How many great discov-eries would never haveoccurred were it not foraccidents?” asks Sherman.
A SPILLfor as p
664
“We were trying to develop a new kind of
rubber for jet aircraft fuel lines,” Sherman
once explained, “when one of the lab assis-
tants accidentally dropped a glass bottle that
contained a batch of synthetic latex I had
made. Some of the latex mixture splashed on
the assistant’s canvas tennis shoe and the
result was remarkable.”
The latex mixture didn’t stain the shoe or
change it in any way. But it simply would not
come off.
Neither soap nor alcohol nor any other
cleaning material could remove the stubborn
mixture from the shoe. In fact, the mixture
actually made water bead and run off the
shoe in much the same way that water runs
off a duck’s back.
Perfecting the ProductAlthough the lab assistant was frustrated
by the mixture’s staying power, Sherman was
inspired. She realized that it could be used to
protect fabrics from oil, water, and dirt. She
spent three years working with another
chemist to perfect the product, which came
on the market in 1956. The substituted
hydrocarbon compound that Sherman devel-
oped makes fabrics more durable as well as
stain resistant. It bonds to the fibers in the
fabric and protects them like an invisible
shield. Today, the carpet in your home, the
fabric that covers the couch in your living
room, and some of the clothes that you wear
are likely treated with the fabric protector
invented by Sherman. Her product is espe-
cially useful on uniforms for people who
spend a lot of time outdoors in difficult, dirty,
or messy situations, such as firefighters,
police officers, and military personnel.
Encouraging Young InventorsSherman had a successful career as a
chemist and inventor before she retired in
1992. She often speaks to students about the
life of an inventor and encourages them to
pursue their dreams. Sherman stresses that a
creative mind is a scientist’s best tool.
“Anyone can become an inventor,” she insists,
“as long as they keep an open and inquiring
mind and never overlook the possible signifi-
cance of an accident or apparent failure.”
For more information, visitscience.glencoe.com
CONNECTIONS Experiment Pour a small amount of water ona piece of cloth that has been treated with fabric protector. Do thesame to a piece of untreated cloth. What happened to the water in bothcases? What happened to the pieces of cloth?
Patsy Sherman and her team have mademud on the rug easier to deal with.
666 CHAPTER STUDY GUIDE
Section 3 Petroleum—A Source of Carbon Compounds
1. Petroleum is a mixture of thousands ofcarbon compounds.
2. A fractionating tower separates petroleuminto groups of compounds or fractionsbased on their boiling points.
3. Small hydrocarbons obtained from petro-leum can be combined to make long chainscalled polymers, which are used for plastics.
4. Polymers can bespun into fibersdesigned to havespecific proper-ties. What prop-erty is importantin spandex fibers?
Section 4 Biological Compounds1. Proteins, nucleic acids, carbohydrates,
and lipids are major groups of biologicalorganic compounds.
2. Many important biological compounds arepolymers, huge organic molecules made ofsmaller units, or monomers.
3. The pain-producing com-ponents of wasp venomare peptides. What are themonomers of peptides?
Section 1 Simple Organic Compounds1. Carbon is an element with a structure that
enables it to form a large number of com-pounds, known as organic compounds.
2. Saturated hydrocarbons contain onlysingle bonds between carbon atoms.Unsaturated hydrocarbons contain doubleor triple bonds.
3. Many camp stoves burn butane. How many carbon atoms are in a butane molecule?
4. Isomers of organic compounds have identi-cal formulas but different molecular shapes.
Section 2 Other Organic Compounds1. Aromatic compounds, many of which have
odors, contain the benzene ring structure.
2. Cookware oftenhas a nonstickcoating. Thiscoating is ahydrocarbon polymer inwhich fluorinereplaces somehydrogenatoms. What aresuch hydrocar-bons called?
3. Benzene rings are stable because all six car-bon atoms are bound tightly on one plane.
4. Aromatic compounds include those havingtwo or more rings fused together.
Use each of the vocabularywords on your Foldablein a complete sentence
that explains something about the organiccompounds discussed in this chapter.
After You ReadFOLDABLESReading & StudySkills
FOLDABLESReading & Study Skills
Study GuideChapter 2121
CHAPTER STUDY GUIDE 667
Vocabulary Wordsa. alcoholb. aromatic
compound c. carbohydrated. deoxyribonucleic
acid (DNA)e. hydrocarbonf. isomerg. lipidh. monomer
i. nucleic acidj. organic compoundk. polyethylenel. polymerm. proteinn. saturated
hydrocarbono. substituted
hydrocarbon p. unsaturated
hydrocarbon
Using Vocabulary Replace the underlined words with the correct
vocabulary words.
1. Isomers are compounds that contain theelement carbon.
2. An alcohol forms a link in a polymer chain.
3. Protein is the nucleic acid that containsyour genetic information.
4. An unsaturated hydrocarbon contains thebenzene-ring structure.
5. Organic compounds such as sugars andstarches are called proteins.
6. Organic compounds such as fats and oilsare called isomers.
7. Lipids are compounds with identicalchemical formulas but different structures.
Think of other ways that you might designan experiment to prove scientific principles.Consider controls and variables.
Study Tip
Study GuideChapter 2121
havehave have have
Carbon
Benzene ringsSinglebonds
OH & COOHGroups
Multiplebonds
forms
includeinclude
include
include include
include
AromaticCompounds
Alcoholsand acids
SaturatedHydrocarbons
Unsaturatedhydrocarbons
Organic compounds
Other organiccompounds
Hydrocarbons
Complete the followingconcept map about types oforganic compounds.
Choose the word or phrase that best answersthe question.
1. How would you describe a benzene ring?A) rare C) unstableB) stable D) saturated
2. How would you classify hydrocarbons, suchas alcohols and organic acids?A) aromatic C) substitutedB) saturated D) unsaturated
3. What are the small units that make up polymers called?A) monomers C) plasticsB) isomers D) carbohydrates
4. What type of compound is hemoglobinfound in red blood cells?A) carbohydrate C) nucleic acidB) lipid D) protein
5. RNA tells your body how to make proteins.What does DNA code and store?A) lipids C) proteinB) nucleic acids D) genetic
information
6. What type of compounds form the DNAmolecule?A) amino acids C) polymersB) nucleotides D) carbohydrates
7. Glucose and fructose both have the formulaC6H12O6. What are such compounds called?A) amino acids C) isomersB) alcohols D) polymers
8. If a carbohydrate has 16 oxygen atoms, howmany hydrogen atoms does it have?A) 4 C) 16B) 8 D) 32
9. What type of compound is cholesterol?A) sugar C) proteinB) starch D) lipid
10. Which petroleum fractions are collected atthe top of a fractionating tower?A) highest boiling C) lowest boilingB) liquid D) polymer
11. Too much saturated or unsaturated fat inyour diet is unhealthful. How do they differin composition?
12. Propyl alcohol and isopropyl alcohol havethe formula C3H80. How might their struc-tures differ?
13. Draw a diagram to explain single, double,and triple bonds in hydrocarbons. Draw achain of carbon atoms that shows each typeof bond.
14. Explain the term fraction when used todescribe the products produced duringpetroleum refining. Describe the process bywhich these products are obtained.
15. Making and Using Graphs Using the fol-lowing table, plot the number of carbonatoms on one axis and the boiling point onthe other axis on a graph. Use the graph topredict the boiling points of butane, octane,and dodecane (C12H26).
16. Recognizing Cause and Effect Anthraceneis a compound containing three fused ringssimilar to the benzene ring. How would youexplain the stability of this compound?
668 CHAPTER ASSESSMENT
Name Formula Boiling Point (ºC)
Methane CH4 –162
Ethane C2H6 –89
Propane C3H8 –42
Hydrocarbons
AssessmentChapter 2121
CHAPTER ASSESSMENT 669
17. Interpreting Scientific IllustrationsWhich of the following terms apply tothe illustration below: alcohol, aromatic,carbohydrate, hydrocarbon, lipid, organiccompound, polymer, saturated, and substi-tuted hydrocarbon.
18. Concept Mapping Make a network tree to describe types of fats. Include the terms saturated fats, unsaturated fats,single bonds, and double bonds.
19. Hypothesizing A weight-reduction dietallows no food other than lettuce and freshfruit for three days a week. What is missingfrom the diet on these days?
20. Scientific Drawing Research threehydrocarbons containing five carbon atoms. Draw diagrams of their structures,name them, and tell their uses.
21. Surveying and Graphing Record the fibercontent of your clothing, noting whether itis synthetic or natural. Make a circle graphcomparing the percentages of natural andsynthetic fibers.
—
H
C C — C — H
H
H
——
H
—
H—
Go to the Glencoe Science Web site at science.glencoe.com or use the Glencoe Science CD-ROM for additionalchapter assessment.
TECHNOLOGY
AssessmentChapter 2121
The common alcohol methanol is represented by the following chemicalsymbol:
Study the chemical formula above andanswer the following questions.
1. According to this chemical formula, allof the following elements are found inmethanol EXCEPT _________.A) carbonB) nitrogenC) hydrogenD) oxygen
2. How many carbon atoms are there inthe compound methanol?F) oneG) twoH) threeJ) four
3. How many electrons are shared in eachof the bonds linking the carbon atomin methanol to the three hydrogenatoms?A) oneB) twoC) threeD) four
Test Practice
CH3OH
Methanol
