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Grade 11
Unit 8
SCIENCE 1108
CARBON CHEMISTRY:
HYDROCARBONS
CONTENTS
I.
II.
CARBON COMPOUNDS . . . . . . . . . . . . . . . . . . . . . . . . .
2
Classification of Organic Compounds . . . . . . . . . . . . .
2
Sources of Organic Compounds . . . . . . . . . . . . . . . . . .
5
CARBON ATOMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Forms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Bonding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
III.
HYDROGEN AND CARBON . . . . . . . . . . . . . . . . . . . . . . 17
Saturated Hydrocarbons . . . . . . . . . . . . . . . . . . . . . . . . 18
Unsaturated Hydrocarbons . . . . . . . . . . . . . . . . . . . . . . 23
Author:
Editor:
Illustrators:
Harold Wengert, Ed.D.
Alan Christopherson, M.S.
Alpha Omega Graphics
804 N. 2nd Ave. E., Rock Rapids, IA 51246-1759
© MM by Alpha Omega Publications, Inc. All rights reserved.
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CARBON CHEMISTRY:
HYDROCARBONS
Our Creator in His wisdom made a universe
that is unique. No length of time nor combination
of circumstances could have produced such a world
as ours. The study of carbon chemistry is truly a
study of God’s creation. You will learn that the
uniqueness of the carbon atom is the basis of all
life. The choice of this atom with its designed characteristics is indeed a mark of an omnipotent
Creator. No work of chance could have happened
upon the combination necessary to produce life.
David proclaimed in Psalm 19:1, “The heavens
declare the glory of God and the firmament
sheweth his handywork.”
Science LlFEPACs 1108 and 1109 will be a
study of the carbon atom and the chemistry of life.
The study of functional groups of organic compounds will help you to see the glory of God in creation. In this LIFEPAC® you will review the atomic nature of carbon and the molecular structure of
carbon compounds. You will also learn more about
hydrocarbons, their sources, and their chemistry.
For anyone interested in medicine, nursing, biology
or chemistry as a career, these two LlFEPACs
should be of special interest.
OBJECTIVES
Read these objectives. The objectives tell-you what you will be able to do when you have successfully completed this LIFEPAC.
When you have finished this LIFEPAC, you should be able to:
1.
2.
3.
4.
5.
6.
7.
Classify compounds as organic or inorganic.
Identify the three major sources of organic compounds.
Describe the structure of the carbon atom.
Identify and to describe the three forms of carbon.
Describe carbon bonding.
Classify alkanes, alkenes, and alkynes.
Describe alkanes, alkenes, and alkynes.
Survey the LIFEPAC. Ask yourself some questions about this study. Write your questions here.
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1
I. CARBON COMPOUNDS
Carbon compounds are a part of the familiar
carbon cycle. The carbon cycle was part of God’s
natural balancing of nature. At the time of the
Flood, nearly all of our coal and petroleum
resources were buried and formed. These carbon
compounds are the basis of all the synthetic
plastics and petrochemicals man has made for
his comfort, as well as his main source of fuel.
In this section you will study the sources and
classification of carbon compounds.
SECTION OBJECTIVES
Review these objectives. When you have completed this section, you should be able to:
1.
2.
Classify compounds as organic or inorganic.
Identify the three major sources of organic compounds.
CLASSIFICATION OF ORGANIC
COMPOUNDS
All substances can be classified into either of
two categories, organic and inorganic. This classification scheme was used by the early chemists in a
slightly different manner than it is being used
today.
Originally, the term organic was used in its
general sense in that rocks and minerals are inorganic; but plants, animals, and the substances they
produce are organic. In this sense, the adjective
organic tells you that a substance is, or has at one
time been, a part of a living organism. An organic
substance according to this classification scheme is
derived from things that are, or have been, alive.
Early definition. This system of classification
was set up because prior to the year 1800, organic
substances were believed to contain a “vital spirit.”
Since no chemist possessed, nor could ever hope to
attain, a “bottle of vital spirit,” laboratory production (except by living things) of organic compounds
was believed to be impossible. Thus two separate
and distinct types of substances were thought to
2
meaning in chemistry today. To illustrate, study
the following exercises with special attention to the
products of these reactions. A student did the following experiment to collect the data for your
study.
One sugar cube (sucrose) was added to a 100 ml
beaker. Enough concentrated H2SO4 (HIGHLY
CAUSTIC) was added to soak the cube completely
(about 2 ml). The mixture was allowed to set for several minutes. One of the products of the reaction
was a gas which he was able to detect by condensing it on the surface of a cool watch glass set on top
of the beaker. The liquid was tested with cobalt
chloride paper (detects H2O) and the paper turned
colors. A solid residue product of the reaction
resembled charred wood or carbon. The reaction
became hot.
exist: organic substances, which were impossible to
synthesize, and inorganic substances, which could
be synthesized. Therefore, originally organic chemistry was founded as the study of compounds from
living things that contained a vital spirit” (acquintessance). Historians of science refer to this theory
as the Theory of Vitalism.
Considerable doubt had begun to cloud this
theory when in 1928, the German chemist
Friedrich Wohler synthesized urea, a compound
normally produced by animal metabolism. While
working with the inorganic compound ammonium
cyanate, he surprisingly discovered crystals of urea
in his beakers. Since then, thousands of organic
compounds have been synthesized, and the Theory
of Vitalism has passed into oblivion.
Modern definition. The terms organic chemistry or organic compound have a slightly different
Do these activities.
1.1
On the basis of the student’s data and observations, complete these activities.
a. What does concentrated H2SO4 do to sucrose? Complete the equation for this reaction.
C12H22O11 + 11 H2SO4 → 12 __________ + 11 H2SO4 + 11 __________
b. Is the concentrated H2SO4 a catalyst in this reaction? __________
c. Explain your answer in b. _______________________________________________________________
___________________________________________________________________________________________
d. What was the gaseous product of this reaction? ___________________
e. Did the reactants give off energy when they formed the products? ___________________
f. Is the reaction exothermic or endothermic? ___________________
g. Do the products or the reactants have more enthalpy? ___________________
h. On the basis of these observations, complete the following diagram.
3
1.2
What is urea? _______________________________________________________________________
_____________________________________________________________________________________
1.3
Describe the Theory of Vitalism. ______________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
1.4
Descirbe Friedrich Wohler’s contribution to science. ____________________________________
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ment carbon. Examination of the compounds from
living things shows an abundance of this element.
Organic chemistry is the study of compounds made
of carbon. Many compounds of this element,
although not products of living things, are classified as organic compounds. Exceptions to the rule
are oxides of carbon (CO and CO2), metal carbonates, and metal cyanides. All of these exceptions
are considered to be inorganic compounds.
Many plastic materials burn and leave a
charred, black residue like that of the H2SO4-sugar
reaction. The products of the preceding reaction
are similar to the results of leaving bread in the
toaster or meat and potatoes in the oven too long.
A hot flatiron left on a piece of cloth yields the
same charred products. Sugar, plastics, food, and
cloth are part of a large group of substances which
have two things in common: (a) they all contain
organic compounds and (b) they all contain the ele-
Do this activity.
1.5
The following circle represents all chemical compounds. Crosshatch organic compounds
vertically and inorganic compounds horizontally on the drawing.
All Organic Compounds
Compounds of Living Things
All Inorganic Compounds
Write true or false.
1.6
___________ Compounds of carbon are organic.
1.7
___________ Organic compounds can not be synthesized.
4
SOURCES OF ORGANIC COMPOUNDS
Since Vitalism is dead, what is so special
about compounds of carbon that they should be
studied separately from the compounds of the
other hundred or so elements? In part, the
answer seems to be that so many carbon compounds exist. About 50,000 compounds of all
the elements other than carbon are known to
exist. Well over a million organic compounds
are known, and every year more than 100,000
new organic compounds are produced.
Carbon atoms can attach themselves to one
another to an extent not possible for atoms of
any other element. Carbon atoms can form
chains thousands of atoms long or rings of all
sizes, such as chains made of paper clips or
strings of popcorn. The chains and rings can
have branches and cross-links with atoms of
other elements (chiefly hydrogen) attached to
the carbon atoms. Each different arrangement
of atoms corresponds to a different compound,
and each compound has its own physical and
chemical properties. Therefore, the order in
which atoms are attached to each other and the
electrons which hold them together are very
important in accounting for the properties of
compounds. Structural formulas and wood models representing molecules can be used to
account for the physical and chemical properties of compounds.
What is significant about carbon that it forms
so many compounds?
Man himself is a walking organic chemical
machine.
The intricate balance between life and death,
learning and forgetting, growing or not growing,
fighting disease or becoming sick is organic in
nature. Any student of medicine or nursing will
certainly need to understand and appreciate the
beauty of this branch of chemistry. The delicate
balance of nature has its foundation in the study
of organic chemistry. Much of our modern day
technology and pollution, especially ecological, is
organic in nature.
Not only is organic chemistry contemporary,
but it is also a clue to the past. Much of the history
5
of the earth and the study of petrology involves the
study of the world of carbon. For example, natural
gas, petroleum, and coal are the largest sources of
carbon compounds. Although many of these materials are used as they are, many compounds from
these sources are used as raw materials for synthesizing new compounds. Coal, for example, has
become such an important source of medicines that
some are advocating developing atomic energy
more rapidly and saving our coal reserves.
Industry makes use of the wide range of boiling
points of compounds in petroleum to separate
crude oil into gasoline, kerosene, fuel oil, and lubricating oil. Complete the last two hydrocarbons in
the chart below.
Crude oil is heated in a large distilling apparatus. The fraction which boils off between 40° to
206°C is collected and sold as gasoline.
Petroleum. Natural gas is about 90 percent
methane (CH4) with some ethane (C2H6) and
propane (C3H8) in it. Natural gas is found in certain porous rock formations. Natural gas is used
for heating buildings, for cooking food, and for a
starting compound to produce other organic substances. Methane, ethane, and propane are colorless and are practically odorless. By law, a sulfurcontaining compound with a distinctive odor must
be added to natural gas before it is distributed for
commercial consumption. The addition of these
substances immediately warns people of the danger of a gas leak, and they can take safety precautions to prevent a fire or explosion.
Petroleum is a primary source of hydrocarbons.
Hydrocarbons are organic compounds composed of
two and only two elements, namely hydrogen and
carbon. The simplest family of hydrocarbons is the
alkanes.
Table 1: Fractions of Petroleum
Fraction
Distillation
Temperature C°
Carbon
Number
Percent
Crude Oil
Below 20°
C1 - C4
2%
Petroleum ether
20 - 60°
C5 - C6
Ligroin
60 - 100°
C6 - C7
2%
Gasoline
40 - 206°
C5 - C10
32%
Kerosene
175 - 325°
C12 - C18
18%
Fuel oil
Above 275°
C12 and higher
20%
Lubricating oil
Nonvolatile
liquids
long chains
Asphalt
Nonvolatile
solids
polycyclic
structures
Natural gas
Coal. The carbon content ranges from 50 to 90
percent in peat, lignite, bituminous coal, and
anthracite. Soft, or bituminous, coal contains less
pure carbon than hard coal, or anthracite. If the
impurities in soft coal are volatile, and if soft coal
is heated in the absence of sufficient air to burn
6
completely to CO2 and H2O, large amounts of pollution occur from the C, CO, and unburned hydrocarbons. Industrial cities that power their plants
with low-grade soft coal have especially large
amounts of pollution from the incomplete combustion of the soft coal.
When coal is heated to a high temperature in
the absence of air, it undergoes decomposition.
Volatile products (coal gas and coal tar) distill off
and a residue called coke remains. The coke is a
valuable industrial material which finds its chief
use in the reduction of iron ore (iron oxide) to iron
for the manufacture of steel. Coke is essentially
carbon that still contains the mineral substances
that are present in all coals (and form the ash that
results when coal or coke is burned).
About eight gallons of coal tar are obtained
from a ton of coal. It is a very complex mixture;
over two hundred different carbon compounds have
been isolated from coal tars. Although the great
value of coal to mankind has been as a fuel, a
source of energy, the many substances in coal gas
and coal tar make coal also an important source of
chemical raw materials.
Plant and animal products. Plants and animals are themselves highly effective chemical factories and they synthesize many carbon compounds useful to man. These useful products
include sugars, starches, plant oils and waxes, fats,
gelatin, dyes, drugs, and fibers.
Wood is a primary product of plant (tree) life.
This organic product is useful to the building
trades, to the paper industry, and as a source of
heat energy for heating and cooking. This product
is again gaining prominence in home use for heating and cooking. As natural gas supplies diminish
and become more expensive, wood will regain
importance in home use.
Complete these statements.
1.8
Well over ______________ different organic compounds are known to exist.
1.9
Each year over ______________ new organic compounds are produced.
1.10
Carbon atoms can form chains ______________ of atoms long.
1.11
A major source of today’s medicines is ______________ .
1.12
Hydrocarbons contain only the elements of a. ____________________________ and
b. ____________________________ .
1.13
The chemicals added to natural gas to give the gas an odor is ______________ .
1.14
Natural gas contains the organic compounds of a. ____________________ ,
b. ____________________ , and c. ____________________ .
1.15
The alkanes in gasoline include a. ____________________ ,
b. ____________________ , c. ____________________ d. ____________________ ,
e. ____________________ , and f. ____________________ .
1.16
The residue of coal decomposition that is used in the manufacture of steel is
called ______________ .
1.17
Three uses for wood include a. ____________________________ ,
b. ____________________________ , and c. ____________________________ .
1.18
A major problem associated with the incomplete combustion of soft coal is ______________ .
1.19
Gasoline is that distillation fraction that has a boiling point range of a. ______________ to
b. ______________ °C .
7
Write true or false.
1.20
___________ There are many more inorganic than organic compounds.
1.21
___________ Carbon chains can form branches and cross-links.
1.22
___________ Man is an organic being.
1.23
___________ The balance of nature has its foundation in the study of organic chemistry.
Balance this equation.
1.24
The manufacture of steel is a very important process. Complete this equation by balancing it..
_______ Fe2O3 + _______ C →_______ Fe + _______ CO2
Do these activities.
1.25
Arrange these alkanes in order of increasing boiling point:
CH4, C6H14 , C2H6, C13H28 , C10H22
a. ____________________
(lowest boiling point)
b. ____________________
c. ____________________
d. ____________________
e. ____________________
(highest boiling point)
1.26
As the number of carbons in the hydrocarbon increases, the boiling point ___________________ .
Adult check ___________________
Initial
Date
Review the material in this section in preparation for the Self Test. The Self Test will check
your mastery of this particular section. The items missed on this Self Test will indicate specific
areas where restudy is needed for mastery.
SELF TEST 1
Answer true or false (each answer, 1 point).
1.01
___________
All carbon compounds are organic compounds.
1.02
___________
All organic compounds are products of living things.
1.03
___________
Organic compounds are carbon compounds.
1.04
___________
Carbon compounds that are organic are products of living things.
1.05
___________
One organic compound is CO2.
1.06
___________
Ammonia, NH3, is an organic compound.
1.07
___________
Methane, CH4, is an organic compound.
8
Match these items (each answer, 2 points).
1.08
_______ number of different organic compounds
a. pollution
1.09
_______ major source of medicine
b. coke
1.010
_______ major problem in burning soft coal
c.
1.011
_______ residue of coal decomposition
d. coal
1.012
_______ first organic compound synthesized
e.
urea
f.
100,000
1,000,000
Complete these statements (each answer, 3 points).
1.013
Three uses for wood include a. ______________________ , b. ______________________ , and
c. ______________________ .
1.014
Carbon atoms can form chains ______________________ of atoms long.
1.015
Hydrocarbons contain only the elements of a. ____________________ and
b. ____________________ .
1.016
The three major sources of organic compounds are a. ______________________ ,
b. ______________________ , and c. ______________________ .
Balance these equations (each answer, 2 points).
1.017
a. _______ CH4
1.018
1.019
+
b. _______ O2
→ c. _______ CO2
+ d. _______ H2O
a. _______ Fe2O3 +
b. _______ C
→ c. _______ Fe
+ d. _______ CO2
a. _______ C
b. _______ O2
→ c. _______ CO
+
Arrange these compounds (each answer, 2 points).
Arrange the following alkanes in order of increasing boiling point:
C20H42 , C16H34 , C2H6 , C150H302 , C11H24 , C32H66 , C9H20.
1.020
____________________
1.021
____________________
1.022
____________________
1.023
____________________
1.024
____________________
1.025
____________________
1.026
____________________
(lowest boiling point)
(highest boiling point)
64
Score
80
Adult Check
_______________
___________________
Initial
9
Date