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Chapter 12
Organic Chemistry
12-1
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Chapter 12 Outline: Main Ideas

Carbon compounds



Organic molecule structures


Formulas and structure
Organic compounds



Bonds and types
Petroleum products
Groups
Polymers
The chemistry of life

Molecules important for biological processes
12-2
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Carbon Compounds
ORGANIC
CHEMISTRY
THE STUDY OF
CARBON-CONTAINING COMPOUNDS
12-3
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Why Is Organic Important?
ORGANIC CHEMISTRY constitutes a separate
branch of chemistry
 We are made of carbon….
 Over 90% of all compounds contain the
element CARBON
 There are over 3 MILLION known organic
compounds


Over 100,000 are added EACH YEAR
CONTRAST: only about 300,000 Inorganic
compounds
12-4
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Know the Difference!
ORGANIC COMPOUNDS
CONTAIN CARBON
INORGANIC COMPOUNDS
DO NOT contain carbon
12-5
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Interesting Organic Trivia

Until around 1850, scientists believed that
organic compounds could only be formed by
LIVING THINGS….
They even considered organic compounds to
have some “VITAL FORCE” associated with
LIFE
 Then, Friedrich Wohler successfully formed a
SYNTHESIS reaction…

NH4OCN  HEAT  NH2CONH2
Ammonium
cyonate
UREA
The primary ingredient in urine
12-6
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Organic Chemistry Is Born


After Wohler’s demonstration…MANY
“natural” organic molecules were produced
by chemists
Then, organic molecules that DO NOT
OCCUR naturally were produced at an ever
increasing pace
12-7
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Organic Chemistry Is Important


Organic chemicals are being introduced into
the environment at an astonishing rate
Organic chemistry has IMPLICATIONS to
a wide variety of fields of study:
MEDICINE
 BIOLOGICAL SCIENCES

Agriculture
 Civil engineering
 Water management

12-8
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Why Is Carbon so Unique?



The carbon atom can form bonds with
MANY other elements
The carbon atom forms a VARIETY of
different bonding structures
We have already seen that the covalent
bonds between carbon atoms can result in
vastly different structures

Graphite, diamond
12-9
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Carbon Is Unique
 The position of the Carbon atom on the
periodic table is a clue to its versatility


Carbon is located midway in its period
This means that the outer electron shell is
HALF FULL


Instead of gaining or losing electrons, carbon has the
natural tendency to SHARE electrons in order to
complete its outer shell
The unique bonding ability of carbon
extends to bonds with other elements as well
12-10
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The Simplest Organic Molecules

Those that contain only CARBON and
HYDROGEN
Very simple structures
Very important variety
We depend STRONGLY on the chemistry of the
hydrocarbons
12-11
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The Alkane Group
 This group of hydrocarbons includes many
familiar gases used in everyday life
12-12
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Some Members of the Alkane Group







Methane……………CH4
Ethane……………….C2H6
Propane………………C3H8
n-Butane………………C4H10
n-Pentane………..……..C5H12
n-Octane………………….C8H18
Note: the natural gas used for household
purposes consists of several alkanes

Primarily methane, about 80%
12-13
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Petroleum Products
Crude oil is the basic raw ingredient for
the production of useful petroleum
based fuels
 This natural resource is a combination
of several alkanes

Those with 5+ carbon atoms
 The exact proportion of each alkane
depends on the source of the crude oil

12-14
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Distillation
 In order to effectively use crude oil,
some alkanes must be at least partially
separated from the rest


This is a difficult process, since the
physical and chemical properties of the
members of the alkane family are very
similar
The solution to this problem is found in
the process of
FRACTIONAL DISTILLATION
12-15
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Using Hydrocarbon Fuels
FRACTIONAL DISTILLATION


REFERS TO THE PRODUCTION OF
SEVERAL HYDROCARBON
COMPOUNDS
Made possible by thoroughly understanding
the detailed properties and small differences
between each of the compounds present in
crude oil
12-16
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Fractional Distillation: Basic Idea
The crude oil is heated
 At each increasing temperature, some
alkanes will evaporate,



Vapors are collected and further refined
to separate the multiple compounds that
may be present in the vapor
This requires a specially engineered
tower
12-17
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More about Fractional Distillation

The natural resource: Crude oil


Each hydrocarbon in crude oil has a different
boiling point


Complicated mixture of hydrocarbons; composition
varies depending on its source
Varies according to the number of carbon atoms their
molecules contain and how they are arranged
Fractional distillation uses the difference in
boiling points and vaporization points to separate
the hydrocarbons present in crude oil
12-18
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Figure 12-2
The
Distillation
Tower
Several
steps are
required
to
produce
fuels
12-19
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Engineering the Tower
 THE FRACTIONING COLUMN
A TUBE, that is cooler at the top than the
bottom
 The boiling vapors cool as they rise
 Vapors condense onto a tray when they reach
the part of the column which is cooler than
their boiling point

12-20
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Reactions Involved in FD
 Catalytic “cracking”

Large hydrocarbon molecules decomposed into
smaller molecules via the introduction of a
catalyst
Requires PRESSURE
 Requires CATALYST ASSISTANCE


POLYMERIZATION

Small light hydrocarbons, synthesized into
larger molecules
12-21
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More on Catalytic Cracking
 “Cracking” is the name given to breaking up
large hydrocarbon molecules into smaller and
more useful bits
 Can be achieved in two ways:
By using high pressures and temperatures without
a catalyst
 Lower temperatures and pressures in the presence
of a catalyst.

12-22
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Useful Catalysts
 The catalyst is not unique
 One common catalyst is small zeolite crystals


The catalyst/hydrocarbon mixture is then
blown reaction chamber at a temperature of
about 500°C.


Zeolite = aluminosilicate mineral
This is called fluid catalytic cracking
The catalyst (solid) remains in a different
phase than the liquids to be separated
12-23
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Organic Molecule Names
 The name simply lists the numbers of
each element present in the compound
 The name does not yield any
information regarding the actual
structure of the molecule
Bonding
 Arrangement


For example, butane is C4H10
12-24
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A Word on Structural Formulas
 A structural formula is a diagrammatic way
to illustrate the actual arrangement of the
atoms in an organic molecule


The arrangement yields information on how the
molecule will interact with other molecules,
depicting how the atoms are bonded to each
other
One useful means of illustrating molecular
structure is by using the
displayed formula
12-25
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The Displayed Formula


A displayed formula shows all the bonds in the
molecule as individual lines. You need to
remember that each line represents a pair of
shared electrons.
Methane (CH4) displayed formula
H
H
C
H
H
12-26
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The Displayed Formula
 The benefit of the displayed formula is that
it gives more information about the
structure of the molecule.


Instead of knowing only how many of each atom, the
structural formal tells us which atoms are bonded to
which other atoms
There is a limitation to the information: the
way the methane is drawn bears no
resemblance to the actual shape of the
molecule.

Methane is not “flat” with 90° bond angles
12-27
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Arrangement Is Important



Some organic chemicals share the same
molecular formula, but have different
properties
An ISOMER is a different arrangement of
the same atoms for a particular organic
species
EXAMPLE butane
12-28
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The Butane Isomer


Butane has the molecular formula: C4H10
The same atoms can be arranged in two different
structures
NORMAL BUTANE
H
H
H
C
H
C
H
C
H
H
H
C
C
C
H
C
H
H
H
H
H
C
H
H
H
H
H
H
ISOBUTANE
12-29
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More about Carbon Bonding

The alkane group contains the simplest
hydrocarbon molecules




Only carbon and hydrogen atoms
Only single covalent bonds between any two atoms
There are other hydrocarbons, also containing
only hydrogen and carbon that exhibit more
complex bonding structures
Due to the unique properties of carbon atoms:

Two carbon atoms can form DOUBLE and TRIPLE
COVALENT BONDS
12-30
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Example
 Consider the molecular formula C2H6
 This is the alkane ETHANE:
H
H
H
C
C
H
Note that the
only difference
H H
is in the bond
between the
 This is also a non-alkane hydrocarbon,
two center
H
H
ETHYLENE:
carbon atoms!
H
C
C
H
H
H
12-31
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Multiple Bonds Affect the Activity
 The alkanes, with only single bonds, are the
least reactive
 Those molecules with double or triple bonds
are more chemically reactive



The presence of a multiple bond means that the
molecule has “room” to add another atom
They are thus called UNSATURATED
The alkanes are called SATURATED, since
other atoms cannot be added to the basic
structure
12-32
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Other Atomic Arrangements
 Not all organic molecules are arranged in a
linear fashion like the ones we have seen
 A special class of organic molecules, called
AROMATIC COMPOUNDS contain a ring
of carbon atoms
 This 6-member carbon ring is called
BENZENE
12-33
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The Benzene Ring
 The BENZENE RING is hexagonal in shape


The bonds between the carbon atoms in the ring
are not simple single bonds.
In addition to the ordinary single bond, an
additional 6 electrons are shared by the carbon
H
atoms
H
C
C
H C
C H
C
H
C
H
12-34
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Aromatic Compounds
 The name aromatic was given to this
class of carbon compounds due to the
strong odor of many of the compounds
Benzene
 Toluene
 Napthalene

12-35
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Two Main Classes
 Organic compounds that contain the ring
structures:
AROMATIC

Organic compounds that do not contain ring
structures:
ALIPHATIC
12-36
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Classification of Organic Chemicals


Compounds that contain elements other
than hydrogen or carbon are considered to
be DERIVATIVES of the more fundamental
carbon-hydrogen combinations that we have
considered thus far.
The basic idea is to substitute an atom or
group of atoms at the location of one of the
hydrogen atoms linked to the carbon chain
that forms the central structure in the
organic molecule
12-37
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The Simplest Substitutions
 The most simple groupings are derived from
the hydrocarbons themselves




The Methyl group 1 C, 3H
The Ethyl group, 2 C, 5 H
The Propyl group, 3 C, 7H
These abbreviations are used in naming
more complex compounds

For example, Methyl Chloride, CH3Cl
12-38
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Functional Groups

Certain sets of atom groups exhibit similar
properties


We saw this in our look at inorganic chemicals,
in particular in acids and bases
In organic compounds, these similar-acting
groups are known as FUNCTIONAL
GROUPS

See Table 12-2 in the text: this table lists a
variety of common functional groups
12-39
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Organic Compound Behavior
 The chemical behavior of organic
compounds is largely determined according
to which functional groups are present
 Each functional group is responsible for
some characteristic of a group of organic
compounds
 These groups include alcohols, ethers,
aldehydes, ketones and organic acids
12-40
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The Alcohol Group
All alcohols contain an OH- group, called the
HYDROXYL GROUP

This is shown in a name by the ending
“ol”


The word alcohol derives from Arabic al-kuhul,
which denotes a fine powder of antimony obtained
by distillation
Alcohol originally referred to any fine powder,
but medieval alchemists later applied the term to
the refined products of distillation
12-41
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Beverage Alcohol
 Ethanol


Physical Properties


Chemical formula: CH3CH2OH
Ethanol melts (or freezes) at about –114.1 °C
(about -173 °F)
Its low freezing point has made it useful as
 The fluid in thermometers for
temperatures below –40 °C, the freezing
point of mercury
 Use as antifreeze in automobile radiators.
12-42
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Ethanol

Has been made since ancient times by the
fermentation of sugars



All beverage ethanol and more than half of
industrial ethanol is still made by this
process.
Simple sugars are the raw material.
Zymase, an enzyme from yeast, changes the
simple sugars into ethanol and carbon
dioxide.
12-43
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Fermentation

The fermentation reaction, is represented by
the simple equation
C6H12O6  2CH3CH2OH + 2CO2


The equation is simple, but the fermentation
process is actually very complex
IMPURITIES IN SOLUTION:

In the production of beverages, such as whiskey
and brandy, the impurities supply the
characteristic flavor.
12-44
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Ethers, Aldehydes and Ketones
 ETHERS



Substances that has an oxygen atom bonded
between two carbon atoms
Widely used as a solvent
ALDEHYDES and KETONES

Both groups contain the CARBONYL ATOM
GROUP:
C
O
12-45
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The Carbonyl Group
 The double bond between the carbon atom
and the oxygen atom on the end of the group
cause strong polarity of this group
 This means that aldehydes and ketones are
readily soluble in water
 Most common ketone: acetone
 Familiar aldehyde: acetaldehyde

This is a product produced by the oxidation of
ethanol and becomes further oxidized to form a
toxic substance, formaldehyde
12-46
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Organic Acids
 This group of organic compounds contain
the COOH or CARBOXYL group


Organic acids have most of the same properties
as ordinary acids, resulting from the liberation
of the H+ ion from the Carboxyl group
Organic acids in everyday experience:



Insect bites: formic acid
Vinegar: acetic acid
Aspirin: acetylsalicylic acid
12-47
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Esters
 When an alcohol reacts with an acid, the
reaction is quite slow when compared with
ordinary inorganic acid-base reactions


This is due to the slow dissociation of the
hydroxide in the alcohol in water
The reaction of the “organic hydroxide”—
the alcohol with the organic acid is very
slow, with the product being a separate
group of organic compounds called
ESTERS
12-48
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Esters


Like ketones, esters are also used as solvents
Esters in everyday life:




Ethyl acetate: used in paint
Propyl acetate: causes the characteristic
fragrance and taste of pears
Butyl butyrate: responsible for the
characteristic fragrance and taste of pineapple
Nitroglycerin: an explosive liquid that was once
the main stay of demolition work
12-49
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Linking Basic Groups Together
 When multiple small organic molecules
are linked together, a long, chain-like
molecule is formed
 These very large molecules are called
POLYMERS

Much of modern life revolves around
the use of polymers
12-50
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Polymers

All man-made plastic materials are
polymers:




Polythene (packing material)
Polyvinylchloride (used for pipes)
Teflon, nylon, dacron, polyester and styrofoam
In addition, many natural substances are
polymers:



Starches
Cellulose (wood fiber)
Proteins
12-51
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Polymer Formation
 Polymers are formed when MONOMERS
bond together to form a long chain-like
molecule
 In the case of polythene, the monomer is the
H
simple ethene molecule H

The double bond
allows this molecule
to easily bond with
other like molecules
C
H
C
H
12-52
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Vinyls
 This group of polymers also begins with the
ethene monomer, but with a slight alteration


One of the hydrogen atoms is replaced by
another atom or group of atoms to form a
VINYL MONOMER
There are a wide variety of vinyl polymers
with a wide variety of applications to
product production

Including polystyrene (Styrofoam)
12-53
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Table 12-3
12-54
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Replacing More Hydrogen Atoms
 The next step in complexity for polymer
molecules is the replacement of a second
hydrogen on the ethene monomer with
another atom or group of atoms
 Example: methacrylate


Marketed under the trade names Lucite and
Plexiglas
This polymer has had tremendous impact on a
variety of human activities due to its ease of
manufacture, light weight, transparency and
durability
12-55
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Other Important Polymer Groups

Teflon



Copolymers


Example: Dynel
used in fiber manufacture
Elastomers



Monomer: tetrafluorethene (all H atoms have been
replaced by fluorine atoms)
Widely used for non-stick coatings and in applications
where chemical inertness is required
These monomers contain some double bonds
Example: neoprene, an elastic fabric material
All types of synthetic fibers use to produce
carpets, clothing, and fabrics of all kinds.
12-56
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Organic Chemicals and Life Processes
 The understanding of nature demands that
we not restrict ourselves to a single scientific
discipline
 The biological world cannot be separated
from the world of the physical sciences,
physics and chemistry
 Organic chemistry plays an integral role in
the understanding of biological processes
12-57
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Carbohydrates
 The name “carbohydrate” is used to
describe a broad class of molecules
composed of
Carbon
Hydrogen
Oxygen
 They are produced primarily by plant
processes, which use light energy from the
sun as the energy source for a chemical
reaction called photosynthesis
12-58
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Carbohydrates
 The term “photosynthesis” provides a clue
about the chemical reaction occurring in
green plants



The reaction is a synthesis reaction whose
product is a long chain molecule
Examples: starches, sugars, cellulose
These substances provide the source of
energy (i.e., FOOD) for other living
organisms
12-59
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A Word on Sugars
 There are several different molecules that
are considered in the class of SUGARS
 Monosaccharides (simple sugars)

Glucose



With isomers FRUCTOSE, GALACTOSE,
MANNOSE
Glucose is the form of sugar circulated in blood
Disaccharides (chains formed from
monosaccharides)

Examples: Sucrose, lactose, maltose
12-60
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More Complex Sugars


A more complex sugar molecule can be formed from the
combination of more than two simple sugars
One example is
POLYSACCHARIDES

This naturally occurring complex sugar is found as
CELLULOSE


Wood, cotton
Another example is
STARCH


This special polysaccharide is slightly different in
structure than cellulose
As a food source, the starch molecule is broken down into
a sugar to be usable by living organisms
12-61
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Photosynthesis





This amazing endothermic chemical reaction is
responsible for feeding all living organisms, either
directly or indirectly
ENERGY SOURCE: SUNLIGHT
REACTANTS: carbon dioxide (CO2) and water
(H2O)
Neither the CO2 or the H2O directly absorb the
energy from the sun to begin the reaction
A catalyst is necessary for this reaction to take
place
12-62
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The Photosynthesis Catalyst
 CHLOROPHYLL



This substance is what contributes to the green
color of most plants
The chlorophyll directly absorbs the energy
from the sun and facilitates the reaction between
the CO2 and the H2O to form the simple sugar
C6H12O6
This simple reaction is responsible for
processing over 70 billion tons of CO2
through plants on a yearly basis
12-63
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Figure 12-21: Photosynthesis
12-64
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Importance of Photosynthesis
 Because oxygen is one of the products
produced in the photosynthesis reaction, this
process helps to maintain the atmospheric
oxygen levels, important for most animal life
on the planet
12-65
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Figure 12-22: Oxygen-Carbon Dioxide Cycle
12-66
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Organic Calories
 Fats, oils, waxes and sterols are collectively
known as LIPIDS
 LIPIDS contain only carbon, oxygen and
hydrogen atoms

The atoms are arranged very differently than in
carbohydrate molecules
12-67
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The Fat Molecule

The general structure of the fat molecule is a
glycerol molecule with three FATTY ACID
molecules bonded to the glycerol

SATURATED fats are those molecules where
which have single bonds

UNSATURATED fats are those molecules with
double bonds between two or more of the carbon
atoms in the structure

POLY UNSATURATED means more that on
double bond per molecule
12-68
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Hydrogenation of Fats
 The discover of this process revolutionized
the packaged food industry
 In the hydrogenation process, a hydrogen
atom is bonded to double bonded carbon
atoms


This SATURATES the previously unsaturated
molecule
The benefit of this process is that those
unsaturated fats which are normally liquid
at room temperature become solidified at
room temperature
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Proteins


Every living cell contains protein
Proteins contain carbon, hydrogen, oxygen,
nitrogen



And sometimes sulfur, phosphorous and other
elements
The “monomer” for building a protein chain
is called an AMINO ACID
Typical protein molecules are VERY large,
with most containing several hundred
carbon atoms!
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Protein Function

Depends on both sequence and structure


The amino acid groups are linked together with
PEPTIDE BONDS, forming POLYPEPTIDE
CHAINS.


Both the order (sequence) and arrangement (structure)
of amino acids in a protein molecule are important in
determining the function of a protein
These chains are generally folded or coiled in a specific
way, depending on the amino acids
The specific arrangement determines how the
protein will interact in its biological setting
12-71
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Amino Acids for Plants

All amino acids contain nitrogen atoms


Since plant sources are ultimately the starting
point for the food chain, formation of amino
acids and then protein in plants is key to
understanding life processes
The nitrogen needed to form amino acids in
plants must come from the soil, rather than
the surrounding atmosphere

The nitrogen gas in the atmosphere is strongly
bonded
12-72
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Nucleic Acids


These organic acids are critically important
for all life processes
Nucleic acid molecules are composed of
NUCLEOTIDES

With the arrangement of these nucleotides
governing the behavior of the acid molecule
12-73
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The Building Blocks of Nucleotides
 Each nucleotide consists of three
components



PHOSPHATE GROUP (PO4)
PENTOSE SUGAR
a sugar which contains 5 carbon atoms
NITROGEN BASE
these have characteristic nitrogen-carbon ring
structures
12-74
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RNA and DNA
 Both RNA and DNA are nucleic acids
 DNA: deoxyribonucleic acid


The pentose sugar for DNA is deoxyribose
The nitrogen bases found in DNA are
adenine, guanine, cytosine, thymine
 RNA: ribonucleic acid


The pentose sugar in RNA is ribose
The nitrogen bases found in RNA are
adenine, guanine, cytosine, uracil
12-75
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The Discovery of DNA
 Watson and Crick discovered the double
helix structure of DNA in 1953
 DNA molecules are the largest known
molecules, but are usually folded up to form
microscopic packages
 The importance of DNA and RNA in living
organisms is tremendous


DNA controls the function of every cell in every
living thing
RNA carries the detailed instructions needed for
the synthesis of DNA
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Figure 12-27:
DNA Structure
12-77
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Origin of Life


It is believed that it was the formation of the
first amino acid that brought about life to this
planet
In 1952, Miller and Urey performed an
important scientific experiment



They placed the “raw ingredients” that are required for
the production of amino acids into a closed vessel
 Water vapor, hydrogen, methane and ammonia
They then passed electric spark through the mixture
They showed that amino acids could be formed
simultaneously under their conditions
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Figure 12-32: The Miller-Urey Experiment
In a simple
experiment,
Miller-Urey
demonstrated
that it was
possible that
amino acids
formed from
the chemicals
present, with
electric sparks
providing
activation
energy
12-79
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Organic Chemistry: Summary




Organic Chemistry is chemistry of carboncontaining compounds
Structural formulas give information about the
numbers of each atom and the bonding between
them
Isomers are compounds that have varied
structural formulas but identical compositions
Carbon atoms can bond with single, double or
triple covalent bonds. Saturated compounds
contain only single bonds; unsaturated
compounds contain one or more double or triple
bonds
12-80
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Organic Chemistry: Summary (2)

Functional group: a group of atoms that determines the
behavior of an organic molecule

Example: carboxyl group (COOH)

Polymer: long chain of monomers (Plastics)

Carbohydrates are composed of C, H, O and are
produced by green plants in the PHOTOSYNTHESIS
process (sugars, starches, cellulose)

Lipids (fats): synthesized from carbohydrates

Protein is the principal constituent of all living matter;
consists of long chain amino acids

DNA and RNA are nucleic acids; consist of long chains of
nucleotides
12-81
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In-Lecture
Quiz Questions
Chapter 11
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In-Lecture Quiz Questions Chapter 11

Those molecules that contain only single
carbon-carbon bonds are called
A.
B.
C.
D.
polycarbonates.
unsaturated.
saturated.
carbonyls.
12-83
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In-Lecture Quiz Questions Chapter 11

The natural gas used for fuel in many
homes is composed primarily of
A.
B.
C.
D.
butane.
methane.
pentane.
ethane.
12-84
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In-Lecture Quiz Questions Chapter 11

The benzene molecule is easy to identify
because
A. it is a ring with 4 carbon atoms.
B. it is an infinite number of carbon atoms in a
ring formation.
C. it is a ring of 6 carbon atoms.
D. it is a helix of carbon atoms.
12-85
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In-Lecture Quiz Questions Chapter 11

All living cells contain mostly
A.
B.
C.
D.
carbohydrates.
protein.
lipids.
ethane.
12-86
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In-Lecture Quiz Questions Chapter 11

In the photosynthesis reaction, what serves
as the catalyst?
A.
B.
C.
D.
chlorophyll
protein
green dye
benzene
12-87
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In-Lecture Quiz Questions Chapter 11

Those organic compounds that do NOT
contain a benzene ring structure are called
A.
B.
C.
D.
aromatic.
aliphatic.
elliptic.
nucleic.
12-88
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In-Lecture Quiz Questions Chapter 11

Which of the following statements is NOT true
regarding the carbon atom?
A. Carbon has a valence structure suitable for
combinations with MANY other atoms.
B. Carbon can form MANY different stable
bonding structures.
C. Carbon has a full outer shell of electrons.
12-89
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In-Lecture Quiz Questions Chapter 11
 Which of the following statements are NOT
true regarding compounds that consist only
of carbon and hydrogen?
A. The chemical behavior of these compounds
can be altered by changing the arrangement
of atoms, even with the same composition
B. These compounds are called hydrocarbons.
C. These compounds come in all phases: solids,
liquids and gaseous.
D. None of the above.
12-90
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In-Lecture Quiz Questions Chapter 11

Organic chemicals are the “chemicals of life.”
A. True
B. False
12-91
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In-Lecture Quiz Questions Chapter 11

The process by which most beverage
ethanol is produced is called
A. nucleosynthesis.
B. photosynthesis.
C. fermentation.
D. distillation.
12-92