Download 724 24. 1 Simple Organic Compounds 24.2 Other Organic

BIG Idea
Most compounds containing the
element carbon are organic
compounds.
24. 1 Simple Organic
Compounds
MAIN Idea Hydrocarbons are
compounds made only of carbon and hydrogen atoms.
24.2 Other Organic
Compounds
MAIN Idea Substituted hydrocarbons contain other elements
besides carbon and hydrogen.
24.3 Petroleum—A Source
of Carbon Compounds
MAIN Idea Petroleum is the
source of carbon compounds
used to make plastics, fossil
fuels, and many other products.
24.4 Biological Compounds
MAIN Idea Proteins, nucleic
acids, carbohydrates, and lipids
are polymers made by plants
and animals.
What’s in the willows?
The bark of willow trees
has been used to treat
pain and fever. Willow
bark contains a compound related to aspirin.
Today, aspirin and thousands of other useful substances are synthesized
from compounds found
in petroleum.
Science Journal
List other medicines from
natural sources, such as
plants.
724
Walter Bibikow/Index Stock Imagery
Start-Up Activities
Carbon, the Organic Element
The element carbon exists in three very different forms: dull, black charcoal; slippery, gray
graphite; and bright, sparkling diamond.
However, this is nothing compared with the
millions of different compounds that carbon
can form. In this lab, you will seek out the
carbon hidden in two common substances.
WARNING: Always use extreme caution
around an open flame. Point test tubes away
from yourself and others.
Organic Compounds Make the
following Foldable to help you
understand the vocabulary
terms in this chapter.
STEP 1 Fold a vertical sheet
of notebook paper
from side to side.
STEP 2 Cut along every third line of only the
top layer to form tabs.
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.
4. Think Critically Based on what you
observed and what remained in the test
tubes, infer what these residues might be.
Build Vocabulary As you read the chapter, list
the vocabulary words about organic compounds
on the tabs. As you learn the definitions, write
them under the tab for each vocabulary word.
Preview this chapter’s content
and activities at
gpscience.com
725
Walter Bibikow/Index Stock Imagery
Simple Organic
Compounds
Reading Guide
Review Vocabulary
■
■
■
■
Identify the difference between
organic and inorganic carbon
compounds.
Examine the structures of some
organic compounds.
Differentiate between saturated
and unsaturated hydrocarbons.
Identify isomers of organic
compounds.
Carbon compounds surround you—
they’re in your food, your body, and
most materials you use every day.
compound: substance formed from
two or more elements
New Vocabulary
compound
•• organic
hydrocarbon
hydrocarbon
•• saturated
isomer
• unsaturated hydrocarbon
Organic Compounds
What do you have in common with your athletic shoes, sunglasses, and backpack? All the items shown in Figure 1 contain
compounds of the element carbon—and so do you. Most compounds containing the element carbon are organic compounds.
At one time, scientists thought that only living organisms
could make organic compounds, which is how they got their
name. By 1830, scientists could make organic compounds in
laboratories, but they continued to call them organic.
Of the millions of carbon compounds known today, more than
90 percent of them are considered organic. The others, including
carbon dioxide and the carbonates, are considered inorganic.
Bonding You may wonder why carbon can form so many organic
Figure 1 Most items used every
day contain carbon.
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CHAPTER 24 Organic Compounds
compounds. The main reason is that a carbon atom has four electrons in its outer energy level. This means that each carbon atom
can form four covalent bonds with atoms of carbon or with other
elements. As you have learned, a covalent bond is formed when two
atoms share a pair of electrons. This large number of bonds allows
carbon to form many types of compounds ranging from small
compounds used as fuel, to complex compounds found in medicines and dyes, and the polymers used in plastics and textile fibers.
Figure 2 Carbon atoms bond to
form straight, branched, and cyclic
chains.
H
H
— —
H
— —
H
— —
H
— —
H
— —
H
— —
compounds is that carbon can link together with other carbon
atoms in many different arrangements—chains, branched
chains, and even rings. It also can form double and triple bonds
as well as single bonds. In addition, carbon can bond with atoms
of many other elements, such as hydrogen and oxygen. Figure 2
shows some possible arrangements for carbon compounds.
— —
Arrangement Another reason carbon can form so many
H
H
H
H
H
H
H
H—C—C—C—C—C—C—C—H
Heptane is found in gasoline.
—
H
H—C—H
H
H
—
C—C—C—C
H
H
H
Isoprene exists in natural rubber.
OH
C
H
C
C—
—
H
— —
C
C— C
—
H
H
O—C—H
—
Carbon forms an enormous number of compounds with
hydrogen alone. A compound made up of only carbon and
hydrogen atoms is called a hydrocarbon. Does the furnace,
stove, or water heater in your home burn natural gas? A main
component of the natural gas used for these purposes is the hydrocarbon methane. The chemical formula of methane is CH4.
Methane can be represented in two other ways, as shown in
Figure 3. The structural formula uses lines to show that four
hydrogen atoms are bonded to one carbon atom in a methane
molecule. Each line between atoms represents a single covalent
bond. The second way, the space-filling model, shows a more
realistic picture of the relative size and arrangement of the
atoms in the molecule. Most often, however, chemists use chemical and structural formulas to write about reactions.
—
Hydrocarbons
C—
H
H
O
Vanillin is found in vanilla flavoring.
Name three ways that chemists represent
organic compounds.
Another hydrocarbon used as fuel is propane. Some stoves,
most outdoor grills, and the heaters in hot-air balloons burn this
hydrocarbon, which is found in bottled gas. Propane’s structural
formula and space-filling model also are shown in Figure 3.
Methane and other hydrocarbons produce more than
90 percent of the energy humans use. Carbon compounds also
are important in medicines, foods, and clothing. To understand
how carbon can play so many roles, you must understand how
it forms bonds.
—
—
H
—
HH
—
H — C— C— C— H
—CC—
—HH
HH—
Methane
CH4
—
H H
HH
—
— —
—
methane, CH4, but bottled gas is
mostly propane, C3H8.
Compare and contrast the two
gases.
—
Figure 3 Natural gas is mostly
H H
H
Propane
C3H8
SECTION 1 Simple Organic Compounds
727
Single Bonds
Table 1 Some Hydrocarbons
In some hydrocarbons, the carbon atoms are
joined by single covalent bonds. Hydrocarbons
containing only single-bonded carbon atoms are
called saturated hydrocarbons. Saturated means
that a compound holds as many hydrogen atoms
as possible—it is saturated with hydrogen atoms.
tructural
Formula
Na
H
|
H—C—H
|
H
H H
|
|
H—C— C—H
|
|
H H
H H H
| | |
H—C— C— C—H
| | |
H H H
H H H H
| | | |
H—C— C— C— C—H
| | | |
H H H H
Me
Eth
Pro
Bu
What are saturated
hydrocarbons?
Table 1 lists four saturated hydrocarbons.
Notice how each carbon atom appears to be a
link in a chain connected by single covalent
bonds. Figure 4 shows a graph of the boiling
points of some hydrocarbons. Notice the relationship between boiling points and the addition of carbon atoms.
Structural Isomers Perhaps you have seen
or know about butane, which is a gas that sometimes is burned in camping stoves and lighters. The chemical
formula of butane is C4H10. Another hydrocarbon called isobutane has exactly the same chemical formula. How can this be?
The answer lies in the arrangement of the four carbon atoms.
Look at Figure 5. In a molecule of butane, the carbon atoms
form a continuous chain. The carbon chain of isobutane is
branched. The arrangement of carbon atoms in each compound
changes the shape of the molecule, and very often affects its
physical properties, as you will soon see. Isobutane and butane
are isomers.
Figure 4 Boiling points of
Boiling Points of Hydrocarbons
50
Boiling point (C)
hydrocarbons increase as the
number of carbon atoms in the
chain increases.
Predict the approximate boiling
point of hexane.
Pentane
0
Butane
Propane
–50
Ethane
–100
–150
Methane
–200
0
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CHAPTER 24 Organic Compounds
1
2
3
4
Number of carbon atoms in chain
5
6
—
H
H
H— C— H
Isobutane
C4H10
—
—
H
H — C— C— C— H
—
—
H
H
—
—
—
—
H H
—
—
H H
H — C— C— C— C— H
———
H
—
H
—
H H
—
Figure 5 Butane has two isomers, one with a straight chain
and the other isomer with a
branched chain.
Butane
C4H10
H
Isomers are compounds that have identical chemical formulas but different molecular structures and shapes. Thousands of
isomers exist among the hydrocarbons. Generally, melting
points and boiling points are lowered as the amount of branching in an isomer increases. You can see this pattern in Table 2,
which lists properties of butane and isobutane.
Sometimes properties of isomers can vary amazingly. For
example, the isomer of octane having all eight carbons in a
straight chain melts at 56.8°C, but the most branched octane
melts at 100.7°C. In this case, the high melting point results
from the symmetry of the molecule and its globular shape. Look
for this isomer when you do the Try at Home MiniLAB.
Other Isomers There are many other kinds of isomers in
organic and inorganic chemistry. Some isomers differ only
slightly in how their atoms are arranged in space. Such isomers
form what often are called right- and left-handed molecules, like
mirror images. Two such isomers may have nearly identical
physical and chemical properties.
Table 2 Properties of Butane Isomers
Property
Butane
Isobutane
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
Description
Modeling Structures
of Octane
Procedure
1. To model octane, C8H18,
a hydrocarbon found in
gasoline, use soft gumdrops to represent carbon
atoms.
2. Use raisins to represent
hydrogen atoms.
3. Use toothpicks for chemical bonds.
WARNING: NEVER eat any
food in the laboratory.
Analysis
1. How do you distinguish
one structure from
another?
2. What was the total number of different molecules
found in your
class?
SECTION 1 Simple Organic Compounds
729
Multiple Bonds
H—C—
—C—H
Ethyne
H
H
C—C
H
H
Ethene
Figure 6 Hydrocarbons
can contain double or triple
bonds between carbon atoms.
Ethyne, also called acetylene,
is used in torches for welding.
Ethene or ethylene gas ripens fruit.
Peaches are among the many fruits that can form
small quantities of ethylene gas, which aids in ripening. Ethylene is another name for the hydrocarbon
ethene, C2H4. This contains one double bond in which
two carbon atoms share two pairs of electrons. The
hydrocarbon ethyne contains a triple bond in which
three pairs of electrons are shared. Hydrocarbons, such
as ethene and ethyne, that contain at least one double
or triple bond are called unsaturated hydrocarbons.
They are shown in Figure 6.
What is another name for ethene?
An easy way to remember what type of
bond a hydrocarbon has is to look at the last
three letters. Compounds ending with –ane
have a single bond; the ending –ene indicates a double bond, and –yne indicates a
triple bond.
Summary
Self Check
Organic Compounds
Most compounds containing the element
carbon are organic compounds.
Carbon can form many compounds because it
has four electrons in its outer energy level.
Carbon can bond with atoms of other elements,
such as hydrogen, oxygen, and nitrogen.
Hydrocarbons
A compound containing only carbon and
hydrogen atoms is a hydrocarbon.
Saturated hydrocarbons contain only single
bonds.
Isomers and Multiple Bonds
Compounds that have identical chemical formulas but different molecular structures are
called isomers.
Unsaturated hydrocarbons contain double and
triple bonds.
1. Explain how organic compounds got this name.
2. Compare and contrast ethane, ethene, and ethyne.
3. Explain the term saturated in relation to hydrocarbons.
With what are such compounds saturated?
4. Describe how boiling and melting points generally vary
as branching in a hydrocarbon chain increases.
5. Think Critically Cyclopropane is a cyclic, saturated hydrocarbon containing three carbon atoms. Draw its structural
formula. Are cyclopropane and propane isomers? Explain.
•
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•
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•
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CHAPTER 24 Organic Compounds
(tl)Jens Jorgen Jensen/The Stock Market/CORBIS, (br)PhotoDisc
6. Ratios The formula for the saturated hydrocarbon
octane is C8 H18. Adding one double bond makes the
hydrocarbon octene, having the formula C8 H16. Write
the formulas of the hydrocarbons formed by adding
one, two, and three more double bonds to octene.
Find the ratio of hydrogen decrease to the number of
double bonds?
gpscience.com/self_check_quiz
Other Organic
Compounds
Reading Guide
Review Vocabulary
Aromatic compounds are building
blocks of thousands of useful
compounds, such as flavorings
and medicines.
compound
•• aromatic
substituted hydrocarbon
• alcohol
Figure 7 You can see the sixcarbon benzene ring in these aromatic compounds.
O
C — OH
O — C — CH3
—
Chewing flavored gum or dissolving a candy mint in your
mouth releases pleasant flavors and aromas. Many chemical
compounds produce pleasant odors but others have less
pleasant flavors and smells. For example, aspirin, which has
an unpleasant, sour taste, and methyl salicylate, the compound that produces the fresh fragrance of wintergreen,
shown in Figure 7. Both of these compounds are considered
aromatic compounds. In addition to the fragrances mentioned here, aromatic compounds contribute to the smell of
cloves, cinnamon, anise, and vanilla.
You might assume that aromatic compounds are so named
because they are smelly—and most of them are. However,
smell is not what makes a compound aromatic in the chemical sense. To a chemist, an
aromatic compound is one that contains a
benzene structure having a ring with six
carbons.
New Vocabulary
O
Aspirin is acetyl salicylic acid.
O
H
—
Aromatic Compounds
structural formula: a molecular
model that uses symbols and bonds
to show relative positions of atoms
C—O—C—H
—
■
Define aromatic compounds.
Identify the nature of alcohols
and acids.
Identify organic compounds you
use in daily life.
—
■
—
■
H
OH
What structure is
found in all aromatic
compounds?
Wintergreen is
methyl salicylate.
SECTION 2 Other Organic Compounds
731
(t)Aaron Haupt, (b)Mark Burnett
Figure 8 Benzene, C6H6,
can be represented in three
ways.
Infer Which method of
representing benzene do
you think chemists use
most often?
H
C—
C
—
H
H
—
C—
C—
C
—
H
C
H
H
Space-filling model
Benzene symbol
Structural formula
Benzene Look at a model of benzene, C6H6, and its structural
formula in Figure 8. As you can see, the benzene molecule has
six carbon atoms bonded into a ring. The electrons shown as
alternating double and single bonds that form the ring are
shared by all six carbon atoms in the ring. This equal sharing of
electrons is represented by the special benzene symbol—a circle
in a hexagon. The sharing of these electrons causes the benzene
molecule to be very stable because all six carbon atoms are
bound in a rigid, flat structure. Many compounds contain this
stable ring structure. The stable ring acts as a framework upon
which new molecules can be built.
What is responsible for the stability of the
benzene ring?
Fused Rings Moth crystals have a distinct odor. One type of
Naphthalene
C10H8
Figure 9 Naphthalene used in
moth crystals is an example of a
fused-ring system.
moth crystal is made of naphthalene (NAF thuh leen). This is a
different type of aromatic compound that is made up of two
ring structures fused together, as shown in Figure 9. Many
known compounds contain three or more rings fused together.
Tetracycline (teh truh SI kleen) antibiotics are based on a fused
ring 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
a cheeseburger with Swiss cheese and serve it on toast. Such substitutions would affect the taste of this cheeseburger.
In a similar way, chemists change hydrocarbons into other
compounds having different physical and chemical properties.
They may include a double or triple bond or add different atoms
or groups of atoms to compounds. These changed compounds
are called substituted hydrocarbons.
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Ken Frick
CHAPTER 24 Organic Compounds
A substituted hydrocarbon has one or more of its hydrogen
atoms replaced by atoms or groups of other elements. Depending
on what properties are needed, chemists decide what to add.
Examples of substituted hydrocarbons are shown in Figure 10.
Carbon Compounds in
Space About five percent
of meteorites contain water
and carbon compounds.
Carbon compounds, such
as formic acid and a form of
acetylene, have been
detected in outer space
using radio telescopes. The
areas where they are found
are thought to be regions
of space where new stars
are forming.
Alcohols and Acids Rubbing alcohol gets its name from the
fact that it was used for rubbing on aching muscles. Rubbing
alcohol is a substituted hydrocarbon. Alcohols are an important
group of organic compounds. They serve often as solvents and
disinfectants, and more importantly can be used as pieces to
assemble larger molecules. An alcohol is formed when –OH
groups replace one or more hydrogen atoms in a hydrocarbon.
Figure 10 shows ethanol, an alcohol produced by the fermentation of sugar in grains and fruit.
Why are alcohols considered substituted
hydrocarbons?
Organic acids form when a carboxyl group, –COOH, is substituted for one of the hydrogen atoms attached to a carbon
atom. Look at Figure 10. The structures of ethane, ethanol, and
acetic acid are similar. Do you see that acetic acid, found in vinegar, is a substituted hydrocarbon? You know some other organic
acids, too—citric acid found in citrus fruits, such as oranges and
lemons, and lactic acid found in sour milk.
Figure 10 Substituted hydro-
H
carbons come in a variety of forms.
— —
— —
H
H — C — C — OH
Most ethanol, C2H5OH, often called
grain alcohol, is obtained from corn.
O
—
H
— —
H H
Ethanol
C2H5OH
H—C—C
OH
H
Acetic acid
CH3COOH
Acetic acid is found
in vinegar.
Cl
Cl
C— C
Cl
Cl
Tetrachloroethene
C2Cl4
Tetrachloroethene is a
compound used in dry
cleaning.
SECTION 2 Other Organic Compounds
733
(l)Aaron Haupt, (c,r)Timothy Fuller
Substituting Other Elements Other atoms besides
Figure 11 Strangely, small
concentrations of foul-smelling
compounds are often found in
pleasant-smelling substances. For
example, the mercaptan in skunk
spray is among the 834 components of coffee aroma.
hydrogen and oxygen can be added to hydrocarbons. One is
chlorine. When four chlorine atoms replace four hydrogen
atoms in ethylene, the result is tetrachloroethene (teh truh klor
uh eth EEN), a solvent used in dry cleaning. It is shown in
Figure 10. Adding four fluorine atoms to ethylene makes a compound that can be transformed into a black, shiny material used
for nonstick surfaces in cookware. Among other possible substituted hydrocarbons are molecules containing nitrogen,
bromine, and sulfur.
When sulfur replaces oxygen in the –OH group of an alcohol,
the resulting compound is called a thiol, or more commonly a
mercaptan. Most mercaptans have unpleasant odors. This can be
useful to animals like the skunk shown in Figure 11.
Mercaptan odors are not only unpleasant, they are also powerful. You can smell skunk spray even in concentrations as low 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. In fact,
smelly mercaptans can save lives. Recall that natural gas has no
odor of its own so it is impossible to smell a gas leak. For this reason, gas companies add small amounts of a mercaptan to the gas
to make people aware of leaks before they become dangerous.
Summary
Self Check
Aromatic Compounds
A compound that contains a benzene ring is
called an aromatic compound.
A benzene molecule contains six carbon
atoms bonded into a ring having alternating
double and single bonds.
Aromatic compounds can contain two or more
fused rings.
Substituted Hydrocarbons
A hydrocarbon having one or more hydrogen
atoms replaced by other atoms or groups of
atoms is called a substituted hydrocarbon.
In alcohols, the OH group is substituted for
a hydrogen atom.
Organic acids contain the group COOH.
Substituted hydrocarbons may contain atoms
of elements, such as chlorine, bromine, fluorine, nitrogen, and sulfur.
1. Describe three ways of representing a benzene molecule.
2. Explain why each of the following is considered a substituted hydrocarbon: tetrachloroethene, ethanol, and
acetic acid.
3. Explain why the benzene ring is so stable.
4. Explain why chemists might want to prepare substituted
hydrocarbons. Give two examples of possible substitutions.
5. Think Critically Chloroethane, C2H5Cl, can be used as a
spray-on anesthetic for localized injuries. How does
chloroethane fit the definition of a substituted hydrocarbon? Diagram its structure.
•
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CHAPTER 24 Organic Compounds
Lynn M. Stone/Index Stock
6. Use Percentages As you have read, the odor of mercaptans can be detected in concentrations as low as
0.5 parts per million. Express this concentration as a
percent.
gpscience.com/self_check_quiz
Alcohol and Organic Acids
Have you ever wondered how chemists change
one substance into another? You have learned
that changing the bonding among atoms holds
the key to that process.
Real-World Question
How can an alcohol change into an acid?
Goals
Procedure
1. Pour 1 mL of 0.01M potassium permanganate solution and 1 mL of 6M sodium
hydroxide solution into a test tube.
2. Add 3 drops of ethanol to the test tube.
3. Stopper the test tube. Gently shake it for
1 min. Observe and record any changes in
the solution for 5 min.
■ Control the immediate environment of a
Conclude and Apply
reaction to produce a specific compound.
■ Gather evidence to form conclusions about
the identity of a new compound formed
from a chemical reaction.
Materials
large test tube and stopper
0.01M potassium permanganate
solution (1 mL)
6M sodium hydroxide solution (1 mL)
ethanol (3 drops)
10-mL graduated cylinder
1. Identify the structural formula for ethanol.
2. Identify the part of a molecule that makes
3.
4.
5.
Safety Precautions
6.
WARNING: Always handle chemicals with care;
immediately flush any spill with water.
a compound an alcohol.
Identify the part of a molecule that identifies a compound as an organic acid.
Explain how you know that a chemical
change took place in the test tube.
Predict the formula of the acid produced
when ethanol undergoes a chemical reaction in the presence of potassium permanganate.
Identify the chemical name of the acid produced from ethanol that is found in vinegar.
Design a table and record what changes
take place in the color of the solution.
Compare your observations with those of
other students in your class. For more help,
refer to the Science Skill Handbook.
LAB
735
Tim Courlas/Horizons Companies
Petroleum—A Source
of Carbon Compounds
Reading Guide
New Vocabulary
■
■
■
Explain how carbon compounds
are obtained from petroleum.
Determine how carbon compounds can form long chains.
Define the terms polymerization
and depolymerization.
Petroleum gives us fuels, plastics,
clothing, and many other products.
Review Vocabulary
condense: to change from gaseous
to liquid state
•• polymer
monomer
•• polyethylene
depolymerization
What is petroleum?
Figure 12 Drilling for petroleum beneath the ocean floor
requires huge platforms.
Ocean surface
Oil platform
Ocean floor
Oil wells
Natural gas
Oil
Rock layers
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CHAPTER 24 Organic Compounds
Do you carry a comb in your pocket or purse? What is it
made from? If you answer plastic, you are probably right, but do
you know where that plastic came from? Chances are it came
from petroleum—a dark, flammable liquid, often called crude
oil, that is found deep within Earth. Like coal and natural gas,
this dark, foul-smelling substance is formed from the remains of
fossilized material. For this reason these substances
often are called fossil fuels.
How can a thick, dark liquid like petroleum be
transformed into a hard, brightly colored, useful
object like a comb? The answer lies in the nature of
petroleum. Petroleum is a mixture of thousands of
carbon compounds. To make items such as combs,
the first step is to extract the crude oil from its
underground source, as shown in Figure 12. Then,
chemists and engineers separate the crude oil into
fractions containing compounds with similar boiling points. The separation process is known as fractional distillation. It takes place in petroleum
refineries. If you have ever driven past a refinery, you
may have seen big, metal towers called fractionating
towers. They often rise as high as 35 m and can be
18 m wide and have pipes and metal scaffolding
attached to the outside.
The Tower Inside the tower is a series of
metal plates arranged like the floors of a
building. These plates have small holes so
that vapors can pass through. On the outside you can see a maze of pipes at various
levels. The tower separates crude oil into
fractions containing compounds having a
range of boiling points. Within a fraction,
boiling points may range more than 100°C.
How It Happens The crude petroleum
Hydrocarbon gases
used for fuels and
plastics
Below 20°C
40°C 200 °C
175°C 275 °C
at the base of the tower is heated to more
than 350°C. At this temperature most
250°C 400 °C
hydrocarbons in the mixture become
vapor and start to rise. The higher boiling
fractions reach only the lower plates before
Above 300°C
they condense, forming shallow pools that
drain off through pipes on the sides of the
tower and are collected.
Above 350°C
Fractions with lower boiling points
may climb higher to the middle plates
Heated
before condensing. Finally, those with the
crude oil
lowest boiling points condense on the topmost plates or never condense at all and
are collected as gases at the top of the
tower. Figure 13 shows some typical fractions 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 interaction of rising vapors with condensed liquid. The processes
involved vary. For example, some towers add steam at the bottom to aid vaporization. The design and process used depend on
the type of crude oil and on the fractions desired.
Gasoline
Kerosene
Jet fuel and diesel oil
Lubricating oil
Asphalt
Figure 13 Typical fractions are
separated in a fractionating tower
by their boiling points.
Infer How might these fractions be
separated further?
Uses for Petroleum Compounds
Some fractions are used directly for fuel—the lightest fractions from the top of the tower include butane and propane. The
fractions that condense on the upper plates and contain from
five to ten carbons are used for gasoline and solvents. Below
these are fractions with 12 to 18 carbons that are used for
kerosene and jet fuel. The bottom fractions go into lubricating
oil, and the residue is used for paving asphalt. Figure 14 shows
the variety of useful products that can be obtained from petroleum, in addition to its use as a fuel.
SECTION 3 Petroleum—A Source of Carbon Compounds
737
VISUALIZING PETROLEUM PRODUCTS
Figure 14
P
etroleum, or crude oil, provides the raw material
for a huge number of products that have become
essential 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.
MEDICINES The active
ingredient in aspirin
used to be extracted
from the bark of
willow trees.Today
it is manufactured
from petroleum.
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 synthetic fibers—polyester and
nylon are petroleum-based.
PRINTING INK
The ink used in
newspapers is made
from carbon black,
another product
from petroleum.
FUELS This commuter jet
is being refueled at an airport. Most of the world’s
petroleum is still used in
the form of fuel.
PLASTICS The durability
of hard plastic makes it
the ideal material for a
cell phone keypad.
738
CHAPTER 24 Organic Compounds
(tl)courtesy Land's End, Inc., (tr)CORBIS, (c)Bernard Roussel/The Image Bank/Getty Images, (bl)George Hall/Check Six/PictureQuest, (br)PhotoDisc
Polymers
Did you ever loop together strips of paper to make paper
chains for decorations, or have you ever strung paper clips
together? A paper chain can represent the structure of a polymer
as shown in Figure 15. Some of the smaller molecules from
petroleum can act like links in a chain. When these links are
hooked together, they make new, extremely large molecules
known as polymers. The small molecule, which forms a link in
the polymer chain, is called a monomer. Mono means one.
How are polymers similar to paper chains or
linked paper clips?
Common Polymers One common polymer or plastic is
made from the monomer ethene or ethylene. Under standard
room-temperature conditions, this small hydrocarbon is a gas.
However, when ethylene combines with itself repeatedly, it
forms a polymer called polyethylene. Polyethylene (pah lee EH
thuh leen) is used widely in shopping bags and plastic bottles.
Another common polymer is polypropylene (pah lee PRO puh
leen) used to make glues and carpets. Often two or more different monomers, known as copolymers, combine to make one
polymer molecule.
Polymers can be made light and flexible or so strong that
they can be used to make plastic pipes, boats, and even some
auto bodies. In many cases, they have replaced natural building
materials, such as wood and metal. Because so many things used
today are made of synthetic polymers, some people call this
“The Age of Plastics.”
Visualizing Polymers
Procedure
1. Use paper clips to represent monomers in a synthetic polymer. Hook about
20 together to make a
chain.
2. Cut 20 strips of colored
paper and mark each with
a different letter of the
alphabet from A to T.
3. Assemble these strips in
random order to make a
paper chain.
Analysis
1. Imagine both chains
extended to contain
10,000 or more units.
Compare them in terms of
ease of construction and
degree of complexity.
2. Compare the paper chains
made by your class. How
many different combinations of letters are there?
Figure 15 Imagine this paper chain extended by 10,000 units. Then
imagine each link as a monomer. Now you have an idea of what a typical
polymer used to make plastic looks like.
SECTION 3 Petroleum—A Source of Carbon Compounds
739
Figure 16 Processing can modify a polymer’s properties.
Polystyrene used in CD cases is clear, hard, and brittle.
Polystyrene used in cups is opaque, lightweight, and foamy.
Designing Polymers The properties of polymers depend
Topic: Polymers
Visit gpscience.com for Web Links
to information about polymers and
plastics.
Activity Find out which polymers can be recycled and how to
identify them.
mostly on which monomers are used to make them. Also, like
hydrocarbons, polymers can have branches in their chains. The
amount of branching and the shape of the polymer greatly
affect its properties.
Polymer materials can be shaped in many ways. Some are
molded to make containers or other rigid materials. Sometimes
the same polymer can take two completely different forms. For
example, polystyrene (pah lee STI reen) that is made from
styrene, shown in Figure 16, forms brittle, transparent cases for
CDs and lightweight, opaque foam cups and packing materials.
To make this transformation, a gas such as carbon dioxide is
blown into melted polystyrene as it is molded. Bubbles remain
within the polymer when it cools, making polystyrene foam an
efficient 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 receive wear
and tear. Others can resist strong impacts. For example, bulletproof vests are made of a tightly woven, synthetic polymer.
Polymer fibers also can be made stretchy and resilient for fabric
products like exercise garments. Some polymers remain rigid
when heated, but others become soft and pliable when heated
and harden again when cooled.
Name some applications of polymer fibers.
740
CHAPTER 24 Organic Compounds
(l)Geoff Butler, (r)Charles D. Winters/Photo Researchers
Other Petroleum Products are obtained by
further purifying petroleum fractions using different techniques to isolate individual compounds. After these are separated, they can be
converted into substituted hydrocarbons, as you
learned in the last section. Chemists use these to
make products ranging from medicines such as
aspirin to insecticides, printers’ ink, and flavorings. Also, aromatic dyes from petroleum have
replaced natural dyes, such as indigo and
alizarin, almost completely. The first synthetic
dye was a bright purple called mauve that was
discovered accidentally in coal tar compounds.
Figure 17 This gazebo, like
Depolymerization Polymers have been used so widely that
many other structures, is built from
100 percent recycled plastics.
disposal has caused problems, because many polymers do not
decompose. One way to combat this is by recycling, which
recovers clean plastics for reuse in new products, as shown in
Figure 17. Many communities recycle plastics.
Another approach involves a process called depolymerization,
that uses heat or chemicals to break the long polymer chain into
its monomer fragments. These monomers can then be reused.
However, each polymer requires a different process, and much
research is needed to make this type of recycling economical.
Summary
Self Check
What is petroleum?
Petroleum, often called crude oil, is a dark,
flammable liquid that is formed from fossilized materials.
Carbon compounds in petroleum can be
separated using fractional distillation.
Petroleum fractions are used directly for fuel
and to make useful substances, such as plastics.
Polymers
Polymers are long chains of repeating chemical units called monomers.
Polymers can be designed with specific properties, such as strength and flexibility.
Common polymers are polyethylene and
polypropylene.
Depolymerization is the process of breaking a
polymer into its components.
1. Identify what physical property is used to separate
petroleum fractions.
2. Explain why some fuels are referred to as fossil fuels.
3. Explain why polymers made from the same monomer
can have physical properties that vary greatly.
4. List some of the fuels obtained from petroleum by fractional distillation.
5. Describe why depolymerization can be an expensive
process.
6. Think Critically Based on the names of the polymers
in this section, what do you think polymers made from
the monomers terpene and urethane are called?
•
•
•
•
•
•
•
7. Calculate If the average molecular weight of an
amino acid is 112, find the approximate molecular
weight of a protein containing 122 amino acids.
gpscience.com/self_check_quiz SECTION 3 Petroleum—A Source of Carbon Compounds
741
courtesy Milmar Company
Biological Compounds
Reading Guide
New Vocabulary
■
H
H
—
—
■
All life processes depend on large
biological compounds.
Compare and contrast proteins,
nucleic acids, carbohydrates,
and lipids.
Identify the structure of polymers
found in basic food groups.
Identify the structure of large
biological polymers.
— —
■
O
N—C—C
H
Review Vocabulary
molecule: neutral particle formed
when atoms share electrons
Biological Polymers
Each amino acid
contains a
carboxylic acid
(–COOH) group.
OH
H
Glycine
Each amino acid
contains an
amine (–NH2)
group.
—
S—H
H—C—H
—
—
O
H
N
H
H
Peptide bonds
link molecules
of amino acids.
—
H—C—H
—
—
N—C—C
O
C—C
—
—
—
— —
O
H
OH
Peptide
Glycyl cysteinate
HOH
Figure 18 In a protein polymer,
peptide bonds link together molecules of amino acids.
742
—
H
H
Cysteine
S—H
H
—
H—N—C—C
H
CHAPTER 24 Organic Compounds
•• protein
nucleic acid
acid (DNA)
•• deoxyribonucleic
carbohydrate
• lipid
OH
Like the polymers that are used to make
the plastics and fibers, biological polymers
are huge molecules. Also, they are made of
many smaller monomers that are linked
together. The monomers of biological polymers are usually larger and more complex
in structure. Still, you can picture a biological monomer as one link in a very long
chain.
Many of the important biological compounds in your body are polymers. Among
them are the proteins, which often contain
hundreds of units.
Proteins
Proteins are large organic polymers
formed from organic monomers called
Water forms in
amino acids. Even though only 20 amino
reaction.
acids are commonly found in nature, they
can be arranged in so many ways that millions of different proteins exist. Proteins
come in numerous forms and make up many of the tissues in
your body, such as muscles and tendons, as well as your hair and
fingernails. In fact, proteins account for 15 percent of your total
body weight.
Figure 19 Four peptide chains coil
around each other in the protein polymer hemoglobin. Each chain has an
atom of iron, which carries oxygen.
Iron atom
carrying oxygen
Protein Monomers Amino acids are the monomers that
combine to form proteins. Two amino acids are shown in
Figure 18. The –NH2 group is the amine group and the
–COOH group is the carboxylic acid group. Both groups
appear in every amino acid.
Amine groups of one amino acid can combine with the
carboxylic acid group of another amino acid, linking them
together to form a compound called a peptide as also shown in
Figure 18. The bond joining them is known as a peptide bond.
When a peptide contains a large number of amino acids—about
50 or more—the molecule is called a protein.
Approximately how many amino acid units does
a protein contain?
Protein Structure Long protein molecules tend to twist and
coil in a manner unique to each protein. For example, hemoglobin, which carries oxygen in your blood, has four chains that coil
around each other as shown in Figure 19. Each chain contains
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 down the
proteins into their amino acid monomers. Then your body uses
these amino acids to make new proteins that form muscles,
blood, and other body tissues.
Organic Chemist Organic
chemists find challenges in
many industries. Areas
such as pharmaceuticals,
polymers, adhesives, fuels,
food additives, cosmetics,
and environmental science
all involve organic chemistry. To prepare for this
career, students should
study as much science as
possible in high school, and
not neglect math. Math is
important in both applied
and theoretical organic
chemistry.
SECTION 4 Biological Compounds
743
David M. Phillips/Visuals Unlimited
Nucleic Acids
Topic: DNA Fingerprinting
Visit gpscience.com for Web links
to information about DNA
fingerprinting.
Activity Research how DNA fingerprints are being used besides
solving crimes and prepare a short
report on one of them.
The nucleic acids are another important group of organic
polymers that are essential for life. They control the activities
and reproduction of cells. One kind of nucleic acid, called
deoxyribonucleic (dee AHK sih ri boh noo klay ihk) acid or
DNA, is found in cells where it codes and stores genetic information. This is known as the genetic code.
Nucleic Acid Monomers The monomers that make up
DNA are called nucleotides. A nucleotide is a complex molecule
that contains one of four organic bases, a sugar, and a phosphate
unit. DNA nucleotides are in chains that are unique to an organism. Two nucleotide chains twist around each other forming
what resembles a twisted ladder called a double helix. The rungs
of the ladder are paired organic bases. There only are two different pairs that can form, as shown in Figure 20. Your genetic
code gives instructions for making other nucleotides and proteins needed by your body.
Selecting a Balanced Diet
hat do you like to eat? You probably
choose your foods by how good they
taste. A better way might be to look at their
nutritional value. Your body needs nutrients like proteins, carbohydrates, and fats to
give it energy and help it build cells. Almost
every food has some of these nutrients in it.
The trick is to pick your foods so you don’t
get too much of one thing and not enough
of another.
W
Identifying the Problem
The table on the right lists
some basic nutrients for a variety of foods. The amount of
the protein, carbohydrate, and
fat is recorded as the number
of grams in 100 g of the food.
By examining these data, can
you select the foods that best
provide each nutrient?
744
CHAPTER 24 Organic Compounds
Solving the Problem
1. Using the table, list the foods that supply
the most protein and carbohydrates.
What might be the problem with eating
too many potato chips?
2. In countries where meat and dairy products are hard to get, people eat a lot of
food made from soybeans. Can you think
of reasons why people might wish to
substitute meat and dairy products with
soybean based products?
Nutritional Values for Some Common Foods
Food (100 g)
Protein (g)
Carbohydrate (g)
Fat (g)
Cheddar cheese
25
1
33
Hamburger
17
23
17
Soybeans
13
11
7
Wheat
15
68
2
Potato chips
7
53
35
DNA Fingerprinting Human DNA contains more than 5 billion base pairs. The DNA of each person differs in some way
from that of everyone else, except for identical twins, who share
the same DNA sequence. The unique nature of DNA
offers crime investigators a way to identify criminals from hair
or fluids left at a crime scene. DNA from bloodstains or cells in
saliva found on a cigarette can be extracted in the laboratory.
Then, chemists can break up the DNA into its nucleotide components and use radioactive and X-ray methods to obtain a picture of the nucleotide pattern. Comparing this pattern to one
made from the DNA of a suspect can link that suspect to the
crime scene.
Carbohydrates
If you hear the word carbohydrate, you
may think of bread, cookies, or pasta. Have
you heard of carbohydrate loading by athletes? Runners, for example, often prepare
for a long-distance race by eating, or loading up on, carbohydrates in foods such as
vegetables and pasta. Carbohydrates are
compounds containing carbon, hydrogen,
and oxygen, that have twice as many hydrogen atoms as oxygen atoms. Carbohydrates
include the sugars and starches.
Base pairs
Nucleotides
Figure 20 DNA models show how nucleotides are
arranged in DNA. Each nucleotide looks like half of a
ladder rung with an attached side piece. As you can
see, each pair of nucleotides forms a rung on the ladder, while the side pieces give the ladder a little
twist that gives DNA the name doubleM613-22C-MSS02
helix.
DNA double helix structure
SECTION 4 Biological Compounds
745
— —
C
— —
H
H
OH
C
O
H
C
H
HO
C
C
OH
H
O
H
H
C
CH2OH
C
OH
HO
H
OH
— —
OH
H
— —
H
C
HO
C
O
H HOCH2
C
C
— —
H
O
— —
C
CH2OH
— —
— —
CH2OH
C
C
H
OH
Glucose C6H12O6
Sucrose C12H22O11
Sugars Sugars are a major group of carbohydrates, as shown
in Figure 21. The sugar glucose is found in your blood and also
in many sweet foods such as grapes and honey. Common table
sugar, known as sucrose, is broken down by digestion into two
simpler 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 is
also a polymer. It is made of units or monomers of the sugar glucose. During digestion, the starch is broken down into smaller molecules of glucose and other similar sugars, which release energy in
your body cells.
Athletes, especially long-distance runners, use starches to
provide high-energy, long-lasting fuel for the body. The energy
from starches can be stored in liver and muscle cells in the form
of a compound called glycogen. During a long race, this stored
energy is released, giving the athlete a fresh burst of power.
Figure 21 Sucrose and glucose
are sugars found in foods. Fruits
contain glucose and another simple
sugar called fructose.
Explain why sugars are
carbohydrates.
Lipids
Fats, oils, and related compounds make up a group of
organic compounds known as lipids. Lipids include animal fats
such as butter, and vegetable oils such as corn oil. Lipids contain
the same elements as carbohydrates but in different proportions. For example, lipids have fewer oxygen atoms and contain
carboxylic acid groups.
Figure 22 Starch is the major component of pasta.
— —
OH
O
C
H
OH
CHAPTER 24 Organic Compounds
(t)Bob Mullenix, (b)Diana Calder/The Stock Market/CORBIS
C
C
OH
O
— —
— —
H
C
H
C
H H
H
OH
C
H H
H
C
C
OH
H
C
O
O
C
H
C
— —
— —
H
C
C
OH
O
— —
C
H
C
H
C
H H
— —
C
O
CH2OH
— —
C
O
C
H H
H
OH
746
O
CH2OH
— —
C
— —
C
H H
CH2OH
— —
— —
CH2OH
H
OH
C
O
Fats and Oils These substances are similar in structure to
hydrocarbons. They can be classified as saturated or unsaturated,
according to the types of bonds in their carbon chains. Saturated
fats contain only single bonds between carbon atoms. Unsaturated
fats having one double bond are called monounsaturated, and
those having two or more double bonds are called polyunsaturated. Animal lipids or fats tend to be saturated and are solids at
room temperature. Plant lipids called oils are unsaturated and are
usually liquids, as shown in Figure 23. Sometimes hydrogen is
added to vegetable oils to form more saturated solid compounds
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 in
the diet may contribute to some heart disease and that unsaturated fats may help to prevent heart disease. It appears that saturated fats are more likely to be converted to substances that can
block the arteries leading to the heart. A balanced diet includes
some fats, just as it includes proteins and carbohydrates.
Cholesterol is another lipid that is often in the news. It is
found in meats, eggs, butter, cheese, and fish. Also, some cholesterol is produced by the body to build cell membranes. It is also
found in bile, a digestive fluid. Too much cholesterol may cause
serious damage to heart and blood vessels, similar to the damage caused by saturated fats.
Figure 23 At room temperature, fats are normally solids, and
oils are usually liquids.
Summary
Self Check
Proteins
Proteins are large organic polymers made
from units called amino acids. Proteins form
the muscles, blood, and other body tissues.
Nucleic Acids
DNA is a nucleic acid built of complex molecules called nucleotides.
DNA is found in the cell nucleus. It codes and
stores genetic information.
Other Large Organic Compounds
Carbohydrates contain carbon, hydrogen, and
oxygen.
Sugars are carbohydrates that provide energy
to your body and starches are large polymers
built of sugar units.
Lipids include fats and oils.
1. List the monomers that make up the following biological polymers: proteins, nucleic acids, and starches.
2. Explain where your body gets the amino acids it needs
to build proteins.
3. Identify the name given to the information transmitted
by DNA.
4. Explain the difference between saturated and unsaturated fats and oils.
5. Think Critically Whole milk contains about 4 percent
butterfat. Explain why you might choose to drink milk
containing 2 percent fat.
•
•
•
•
•
•
gpscience.com/self_check_quiz
6. Use Percentages You have read that your body is
about 15 percent protein. Calculate the weight of
protein in your body in kilograms.
SECTION 4 Biological Compounds
747
Ken Frick
PREPARING AN ESTER
Real-World Question
Goals
■ Prepare an ester from
an alcohol and an acid.
■ Detect the results of
the reaction by the
odor of the product.
Materials
medium-size test tube
test-tube holder
250-mL beaker
10-mL graduated cylinder
water
hot plate
ring stand
thermometer
salicylic acid (1.0 g)
amyl alcohol (2 mL)
concentrated sulfuric acid
(1 mL to be added by
teacher)
Are esters aromatic compounds? Organic compounds known as acids
and alcohols react to form another type of organic compound called
an ester. Esters frequently produce a recognizable and often pleasant
fragrance, even though they are not aromatic in the chemical
sense—they might not contain a benzene ring. Esters are responsible
for many fruit flavors, such as apple, pineapple, pear, and banana.
How do an acid and an alcohol combine to produce a compound with
different characteristics? Can the presence of the new compound
formed be detected by its odor?
Procedure
WARNING: Any compound you can smell has entered your body, and
unknown compounds can be toxic or corrosive.To detect an aroma safely,
hold the container about 10 cm in front of your face and wave your hand
over the opening to direct air currents to your nose.
See the illustration below for the proper way to detect odors in the
laboratory. dor, waft the vapor
rd your face gently.
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.
1. Add about 150 mL of water to the beaker and heat it on the hot
plate to 70°C.
2. Place approximately 1 g of salicylic acid in a test tube. Does this
material have an odor?
748
CHAPTER 24 Organic Compounds
3. Add 2 mL of amyl alcohol to the test tube. Before adding it, check to see if this
compound has an odor. If so, try to remember what it smells like.
4. Ask your teacher to add carefully 1 mL of concentrated sulfuric acid.
5. Place the test tube in the hot water and leave it untouched for about 12 to 15
minutes.
6. Remove the tube from the hot water using a test-tube holder and allow it to
cool. Check to see if you can detect a new aroma.
Analyze Your Data
1. What did you smell in step 6?
2. Look closely at the surface of the liquid in the test tube. Do you see any small
droplets of an oily substance? What do you think it is?
Conclude and Apply
1. Predict What esters would form if amyl alcohol was replaced by the following
alcohols; methyl, ethyl, propyl, and isobutyl.
2. Predict Look at the equation for the reaction below. One product is given.
What do you think is the second product formed in this reaction?
—
—
—
—
—
—
—
H
—
H
—
OH
H
—
O
—
C — OH CH3 (CH2)3 CH2OH →
H
—
OH
—
—
H
O
H
H
H
H
H
C—O—C—C—C—C—C—H ?
Write a description of your experiment in
your Science Journal. Suggest how you
might modify the experiment to produce a
different ester. For more help, refer to the
Science Skill Handbook.
LAB
749
Matt Meadows
SOMETIMES
GREAT
DISCOVERIES
HAPPEN BY
ACCIDENT!
A S PI
L
for a Spill L
I
n 1953, American chemist Patsy Sherman
invented a way to protect fabrics from
accidental spills. Strangely enough, this
discovery came about because of an accidental spill in her lab.
The technicians were trying to develop a
new kind of latex rubber for jet aircraft fuel
lines when some of the latex mixture accidentally splashed on an assistant’s canvas
tennis shoe. 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,
water beaded and ran off the shoe, much as
water runs off a duck’s back.
Although her 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
“How many great
discoveries would
never have occurred
were it not for
accidents?” asks
Sherman.
hydrocarbon compound that Sherman developed makes fabrics more durable as well as
stain resistant. It bonds to the fibers in the fabric and protects them like an invisible shield.
The fabric protector invented by Sherman
was used widely to protect many household
products, and some clothing, for over 40
years. It was long believed to be chemically
inert, however, later studies showed that it
does break down slowly, yielding a chemical
called PFOS. This substance can persist for
long periods in the environment and can bind
to human and animal proteins. For this reason, Sherman’s original product was removed
from the market and replaced by a similar
compound that has been shown to present
no danger to the environment.
Now retired, Patsy Sherman often speaks
to students. She 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 significance of an accident
or apparent failure.”
Experiment
Pour a small amount of water on a piece
of cloth that has been treated with fabric protector. Do the
same to a piece of untreated cloth. What happened to the
water in both cases? What happened to the pieces of cloth?
courtesy 3M
For more information, visit
gpscience.com/oops
4. Aromatic compounds include those having
two or more rings fused together.
Simple Organic
Compounds
1. Carbon is an element with a structure that
enables it to form a large number of compounds, known as organic compounds.
2. Saturated hydrocarbons contain only
single bonds between carbon atoms.
Unsaturated
hydrocarbons
contain double or triple
bonds.
3. Many camp
stoves burn
butane.
4. Isomers of
organic compounds have identical formulas
but different molecular shapes.
Petroleum—A Source of
Carbon Compounds
1. Petroleum is a mixture of thousands of
carbon compounds.
2. A fractionating tower separates petroleum
into groups of compounds or fractions
based on their boiling points.
3. Small hydrocarbons obtained from petroleum can be combined to make long chains
called polymers,
which are used for
plastics.
4. Polymers can be
spun into fibers
designed to have
specific properties.
Other Organic Compounds
1. Aromatic compounds, many of which have
odors, contain the benzene ring structure.
2. Cookware often
has a nonstick
coating. This
coating is a
hydrocarbon
polymer in
which fluorine
replaces some
hydrogen
atoms.
Biological Compounds
1. Proteins, nucleic acids, carbohydrates, and
lipids are major groups of biological organic
compounds.
2. Many important biological compounds are
polymers, huge organic molecules made of
smaller units, or
monomers.
3. The pain-producing
components of wasp
venom are peptides.
3. Benzene rings
are stable
because electrons are shared by all six carbon
atoms, resulting in a rigid planar structure.
gpscience.com/interactive_tutor
Use the Foldable that you made at the beginning of this chapter to help you review organic compounds.
CHAPTER STUDY GUIDE
751
(tl)Francis & Donna Caldwell/Visuals Unlimited, (tr)Richard Hutchings/Photo Researchers, (bl)PhotoDisc, (br)Bob Coates/Index Stock
alcohol p. 733
aromatic compound
p. 731
carbohydrate p. 745
deoxyribonucleic acid
(DNA) p. 744
depolymerization p. 741
hydrocarbon p. 727
isomer p. 729
lipid p. 746
monomer p. 739
nucleic acid p. 744
organic compound p. 726
polyethylene p. 739
polymer p. 739
protein p. 742
saturated hydrocarbon
p. 728
substituted hydrocarbon
p. 732
unsaturated hydrocarbon
p. 730
Fill in the blanks with the correct vocabulary
word(s).
1. _________ are defined as compounds that
contain the element carbon.
2. Amino acids combine to form large organic
polymers known as _________.
3. _________ is the nucleic acid that contains
your genetic information.
4. A(n) _________ is defined as a compound
containing the benzene-ring structure.
5. Organic compounds such as sugars and
starches are called _________.
6. Organic compounds such as fats and oils
are called _________.
7. _________ are compounds with identical
chemical formulas but different structures.
9. What are the small units that make up
polymers called?
A) monomers
C) plastics
B) isomers
D) carbohydrates
10. What type of compound is hemoglobin
found in red blood cells?
A) carbohydrate
C) nucleic acid
B) lipid
D) protein
11. What type of compounds form the DNA
molecule?
A) amino acids
C) polymers
B) nucleotides
D) carbohydrates
12. Glucose and fructose both have the formula
C6H12O6. What are such compounds called?
A) amino acids
C) isomers
B) alcohols
D) polymers
13. If a carbohydrate has 16 oxygen atoms,
how many hydrogen atoms does it have?
A) 4
C) 16
B) 8
D) 32
14. What type of compound is cholesterol?
A) sugar
C) protein
B) starch
D) lipid
15. Which petroleum fractions are collected at
the top of a fractionating tower?
A) highest boiling C) lowest boiling
B) liquid
D) polymer
Interpreting Graphics
16. Copy and complete the following concept
map about types of hydrocarbons.
Choose the word or phrase that best answers the
question.
8. How would you describe a benzene ring?
A) rare
B) stable
C) unstable
D) saturated
752
CHAPTER REVIEW
include
include
Unsaturated
hydrocarbons
have
have
Single
bonds
gpscience.com/vocabulary_puzzlemaker
Use the table below to answer questions 17 and 18.
Hydrocarbons
N
Point (°C)
M
162
E
⫺89
P
⫺42
17. Using the table above, plot the number of
carbon atoms on one axis and the boiling
point on the other axis on a graph. Use
the graph to predict the boiling points of
butane, octane, and dodecane (C12H26).
18. How might your graph be different, if
one of the hydrocarbons you plotted had a
branched chain instead of a straight chain?
19. Look at the fiber content of ten items of
your clothing. Note the percentages of
synthetic or natural fibers. Determine the
contents of these items by making a circle
graph comparing the average percentages
of natural and synthetic fibers. Hint: cotton, linen, wool, and silk are natural fibers.
23. Describe how the structures of propyl
alcohol and isopropyl alcohol might differ,
although both have the formula C3H8O.
24. Explain single, double, and triple bonds in
hydrocarbons by drawing a chain of carbon that shows each type of bond.
25. Solve One-Step Equations Although physicians disagree about what is a healthy
level of blood cholesterol, many feel that
levels above 200 mg/dL are harmful.
A patient’s blood cholesterol level measured 228 mg/dL. After two months on
a low-fat diet, it dropped to 210 mg/mL.
By what percent did the patient’s cholesterol level decrease?
26. Use Percentages The label on a bottle of
vinegar containing 473 mL says that
the contents contain 6 percent acid by
volume. How many milliliters of acid
does this bottle contain?
Use the graph below to answer question 27.
21. Classify the following compounds as
saturated, unsaturated, or substituted
hydrocarbons: hexene, isopropyl alcohol,
2-chlorobutane, pentadiene, and butyric acid.
22. Explain why the toughness and durability
of many plastic polymers can be both an
asset and a liability.
gpscience.com/chapter_review
70
60
50
40
30
20
10
0
19
90
19
91
19
92
19
93
19
94
19
95
19
96
19
97
19
98
19
99
20. Infer A healthy diet contains a variety of
nutrients, including fats. However, as you
have read, saturated fats have some drawbacks. Based on this knowledge, how
would you modify your diet to make it
healthier? What general rule would you
apply in making your choices?
Percent
Curbside Recycling
27. Use Statistics The graph above shows
the percent of the U. S. population
served by curbside recycling from
1990 to 1999. Calculate what percent
of the population received service
from 1992 to 1999.
CHAPTER REVIEW
753
Use the illustrations below to answer questions
2 and 3.
H
—
—
—
H H
—
—
—
H — C— C— C— H
H H
H
2. What is the chemical formula of the compound shown above?
A. C3H3
C. C6H6
B. CH8
D. C3H8
3. What is the name of this compound?
A. propane
C. isoprene
B. heptane
D. methane
4. Which of these contains carbon, hydrogen,
and oxygen, and has twice as many
hydrogen atoms as oxygen atoms?
A. hydrocarbon
C. alcohol
B. carbohydrate
D. isomer
H — C — C — OH
H H
Ethanol
C2H5OH
H
O
—
H
— —
H
— —
1. What atoms make up a hydrocarbon
molecule?
A. oxygen, carbon, and hydrogen
B. nitrogen and carbon
C. carbon and hydrogen
D. oxygen and hydrogen
Use the illustrations below to answer questions
7 and 8.
— —
Record your answers on the answer sheet
provided by your teacher or on a sheet of paper.
H—C—C
OH
H
Acetic acid
CH3COOH
754
STANDARDIZED TEST PRACTICE
Cl
C— C
Cl
Cl
Tetrachloroethene
C2Cl4
7. Each of these compounds can be considered to be a substituted hydrocarbon. What
does this mean?
A. Their basic structural unit is a benzene
ring.
B. They are inorganic compounds.
C. One or more of the hydrogen atoms is
replaced by atoms or groups of other
elements.
D. They are polymers.
8. Which of these compounds is an alcohol
that is often obtained from corn?
A. ethanol
B. acetic acid
C. tetrachloroethene
D. ethene
9. Which of these best shows the shape of the
nucleic acid DNA?
A.
C.
B.
D.
5. Which of the following is NOT a polymer
derived from petroleum?
A. polypropylene C. polyethylene
B. acetylene
D. polystyrene
6. Which of the following is a type of recycling that breaks up the polymers into their
original monomers?
A. fractionation
C. isomerization
B. saturation
D. depolymerization
Cl
Record your answers on the answer sheet
provided by your teacher or on a sheet of paper.
10. Describe the type of bonds carbon can
form.
Use the illustrations below to answer question 11.
Record your answers on a sheet of paper.
16. Describe useful properties of polymers.
List several objects made of polymer
material that would likely have been
made of wood or metal in the past.
17. Identify the polymer material used to
make CD cases and foam drinking cups.
How can it be used to create two types
of containers that have such different
properties?
Use the illustration below to answer questions
18 and 19.
11. These molecules are isomers. Given the
information that these are hydrocarbons,
write their chemical formulas.
12. Describe the general relationship between
melting point, boiling point, and the
amount of branching in an isomer.
13. Describe some properties and uses of
alcohols.
14. What is the process used to separate
petroleum compounds called? On what
physical property is this process based?
15. Identify some fractions into which crude
petroleum is separated.
Formulas Think about structural formulas before answering
the question.
Question 11 Remember how many bonds each carbon atom
can form.
gpscience.com/standardized_test
18. How is this paper chain a good representation of a protein? Describe the importance of proteins in the human body.
19. Draw a section of this polymer with three
or four links using the formulas of the two
amino acids given in the chapter and label
each link.
20. When you read or hear about cholesterol
in the news, it is usually associated with
negative effects on the heart and blood
vessels. Why does the body make a substance that can potentially damage the
circulatory system?
21. Plastic polymers can be prepared cheaply
to replace more expensive natural substances. However, disposal presents problems because they do not decompose
readily in landfills. Describe two ways of
solving this problem.
STANDARDIZED TEST PRACTICE
755