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10
General, Organic, and
Biochemistry, 8e
Bettelheim, Brown,
Campbell, and Farrell
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10-1
10 Chapter 10
Organic Chemistry
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10-2
10 Organic Chemistry
• Organic chemistry: the study of the compounds
of carbon.
• Organic compounds are made up of carbon and only a
few other elements.
• chief among these are hydrogen, oxygen, and nitrogen
• also present are sulfur, phosphorus, and halogens
(fluorine, chlorine, bromine, or iodine)
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10-3
10 Organic Chemistry
• Why is organic chemistry a separate discipline
within chemistry?
• Historical: scientists at one time believed that a
“vital force” present in living organisms was
necessary to produce an organic compound.
• The experiment of Wöhler in 1828 was the first in a
series of experiments that led to the demise of the vital
force theory.
NH4 Cl + AgNCO
A mmonium Silver
ch loride
cyan ate
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heat
O
H2 N-C-NH2 + AgCl
U rea
Silver
chloride
10-4
10 Organic Chemistry
• The sheer number of organic compounds
• Chemists have discovered or made over 10 million
organic compounds and an estimated 100,000 new
ones are discovered or made each year.
• By comparison, chemists have discovered or made an
estimated 1.7 million inorganic compounds.
• Thus, approximately 85% of all known compounds are
organic.
• The link to biochemistry
• Carbohydrates, lipids, proteins, enzymes, nucleic
acids, hormones, vitamins, and almost all other
chemicals in living systems are organic compounds.
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10-5
10 Organic Chemistry
• a comparison of organic and inorganic compounds
Organi c Comp ound s
Ino rg an ic Co mpou nds
Bond ing is almost entirel y co val ent
May be g ases, li quid s, o r so li ds
w ith l ow melti ng po ints (l ess
than 360°C)
Mo st are i nsol ubl e in w ater
Mo st are so lu ble i n o rg an ic so lv en ts
such as d iethy l ether, to luene, and
dichl orometh ane
Aqu eo us so lutio ns do n ot
condu ct el ectrici ty
Al most all burn
M ost have i oni c bo nds
M ost are sol id s w ith h ig h
melting po in ts
Reacti ons are usuall y sl ow
Reactio ns are o ften very fast
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M any are so lu ble i n w ater
A lmo st al l are i nso lubl e in
o rgani c so lvents
A queous sol uti ons cond uct
electrici ty
V ery f ew burn
10-6
10 Organic Structure
• Structural formula: shows the atoms present in a
molecule as well as the bonds that connect them.
• VSEPR model: the most common bond angles are
109.5°, 120°, and 180°.
HH
HH
H
C C
H-C C-H
H
H
Eth ylen e
(bond angles
120°)
Acetylene
(bond an gles
180°)
H-C-C-Cl :
HH
Ch loroeth ane
(bond angles
109.5°)
H
:
:
: :
: :
H
H
H
H-C-N-H
H-C-O-H
C O
H
H
HH
Methanol Formald ehyde Methan amin e
(b ond angles (bond angles
(bond angles
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109.5°)
120°)
109.5°)
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: :
H-C-C-H
HH
Eth ane
(bond angles
109.5°)
H
C N
H
H
Methyleneimine
(bond angles 120°)
10-7
10 Organic Structure
• Among neutral (uncharged) organic compounds:
• Carbon: normally forms four covalent bonds and has
no unshared pairs of electrons.
• Hydrogen: forms one covalent bond and no unshared
pairs of electrons.
• Nitrogen: normally forms three covalent bonds and has
one unshared pair of electrons.
• Oxygen: normally forms two covalent bonds and has
two unshared pairs of electrons.
• Halogen: normally forms one covalent bond and has
three unshared pairs of electrons.
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10-8
10 Functional Groups
• Functional group: an atom or group of atoms
within a molecule that shows a characteristic set
of predictable physical and chemical properties.
• Functional groups are important because
• They undergo the same types of chemical reactions no
matter in which molecule they are found.
• To a large measure they determine the chemical and
physical properties of a molecule.
• They are the units by which we divide organic
compounds into families.
• They provide the basis on which we derive names for
organic compounds.
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10-9
10 Functional Groups
• Six common functional groups
Family
Functional
group
Example
Name
Alcohol
- OH
CH3 CH2 OH
Ethanol
Amine
CH3 CH2 NH 2
O
CH3 CH
O
CH3 CCH3
O
CH3 COH
Ethanamine
Carboxylic acid
- NH2
O
- C- H
O
- CO
- C- OH
Carboxylic ester
O
- C- OR
O
CH3 COCH 2 CH 3
Aldehyde
Ketone
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Ethanal
Acetone
Acetic acid
Ethyl acetate
10-10
10 Alcohols
• Alcohol: contains an OH (hydroxyl) group bonded
to a tetrahedral carbon atom. For example,
ethanol:
:
R
R-C-O-H
R
Function al group
(R = H or carbon
goup
:
HH
H-C-C-O-H
HH
S tructural
formula
CH3 CH2 OH
Cond ensed
stru ctural
formu la
• may be primary (1°), secondary (2°), or tertiary (3°)
H
CH3 -C-OH
H
A 1° alcohol
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H
CH3 -C-OH
CH3
CH3 -C-OH
CH3
A 2° alcohol
CH3
A 3° alcoh ol
10-11
10 Alcohols
• Problem: draw Lewis structures and condensed
structural formulas for the two alcohols with the
molecular formula C3H8O.
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10-12
10 Alcohols
• Problem: draw Lewis structures and condensed
structural formulas for the two alcohols with the
molecular formula C3H8O.
• Solution:
Cond ensed stru ctural
: :
Lew is stuctu res
HH H
H-C-C-C-O-H
HH H
formulas
CH3 CH2 CH2 OH
A p rimary alcohol
H
H:O: H
OH
H C-C-C-H
HH H
CH3 CHCH3
A secon dary alcohol
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10-13
10 Amines
• Amine: a compound containing an amino group.
• the amino group may be primary (1°), secondary (2°), or
tertiary (3°).
CH3 NH2
CH3 NH or (CH3 ) 2 NH
Methylamin e
(a 1° amine)
CH3
D imethylamin e
(a 2° amine)
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CH3 NCH3 or (CH3 ) 3 N
CH3
Trimethylamin e
(a 3° amine)
10-14
10 Amines
• Problem: draw condensed structural formulas for the
two primary amines with the molecular formula C3H9N.
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10-15
10 Amines
• Problem: draw condensed structural formulas for the
two primary amines with the molecular formula C3H9N.
• Solution:
NH2
C-C-C-NH2
C-C-C
Th e three carbon s may
be bond ed to n itrogen
in tw o w ays
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CH3 CH2 CH2 NH2
NH2
CH3 CHCH3
Add s even hydrogens to give each
carbon four b on ds an d give the
correct molecu lar formula
10-16
10 Aldehydes and Ketones
• Both contain a C=O (carbonyl) group.
• Aldehyde: contains a carbonyl group bonded to a
hydrogen; in formaldehyde, the simplest aldehyde, the
carbonyl group is bonded to two hydrogens.
• Ketone: contains a carbonyl group bonded to two
carbon atoms.
RO
R C-C-H
O
CH3 CH
R
Fun ctional A cetaldeh yde
grou p
(an aldehyde)
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RO R
O
R C-C-C R CH3 CCH3
R R
Functional
group
Acetone
(a ketone)
10-17
10 Aldehydes and Ketones
• Problem: draw condensed structural formulas for the
two aldehydes with the molecular formula C4H8O.
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10-18
10 Aldehydes and Ketones
• Problem: draw condensed structural formulas for the
two aldehydes with the molecular formula C4H8O.
• Solution:
• First draw the functional group of an aldehyde and add
the remaining three carbons; these may be bonded in
two ways.
• Then add the seven hydrogens necessary to complete
the four bonds of each carbon.
O
CH3 CH2 CH2 CH
or
CH3 CH2 CH2 CHO
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O
CH3 CHCH
CH3
or
CH3 CHCHO
CH3
10-19
10 Carboxylic Acids
• Carboxylic acid: a compound containing a -COOH
(carboxyl: carbonyl + hydroxyl) group.
• In a condensed structural formula, a carboxyl group
may also be written -CO2H.
O
O
CH3 COH
RCOH
Fu nctional
Acetic acid
group
(a carb oxylic acid )
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10-20
10 Carboxylic Acids
• Problem: draw a condensed structural formula for the
single carboxylic acid with the molecular formula
C3H6O2
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10-21
10 Carboxylic Acids
• Problem: draw a condensed structural formula for the
single carboxylic acid with the molecular formula
C3H6O2
• Solution: the only way the carbon atoms can be written
is three in a chain; the -COOH group must be on an end
carbon of the
O chain.
CH3 CH2 COH or CH3 CH2 COOH
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10-22
10 Functional Groups
• Carboxylic ester: a derivative of a carboxylic acid
in which the H of the carboxyl group is replaced
by a carbon group.
O
C-O–C
Functional
group
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O
CH3 -C- O-CH3 or CH3 COOCH3 or CH3 CO 2 CH 3
Methyl acetate
(an ester)
10-23
10 Chapter 10 Organic Chemistry
End
Chapter 10
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10-24