Chapter 1
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)
Why Carbon?

Why is organic chemistry a separate
discipline within 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.

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
heat
O
H2 N-C-NH2 + AgCl
U rea
Silver
chloride
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
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
H
CH 2OH
H
HO
O
H
H
H
H
O
CH 2OH
HO
HO
H
O
OH
H
Sucrose (table sugar)
OH
Na+ Cl-
H
Sodium chloride (table salt)
Structure

Structural formula: shows the atoms
present in a molecule as well as the bonds
that connect them.

Lewis structure: A molecular
representation that shows both the
connections among atoms and the
locations of lone-pair valence electrons.

Common bonding patterns for C, N, O, X,
and H
•
VSEPR model: the most common bond
angles are 109.5°, 120°, and 180°.
HH
H
C C
HH
Eth ane
(bond angles
109.5°)
H
H
Eth ylen e
(bond angles
120°)
H-C C-H
H-C-C-Cl :
Acetylene
(bond an gles
180°)
HH
Ch loroeth ane
(bond angles
109.5°)
H-C-O-H
C O
H
H
HH
Methanol Formald ehyde Methan amin e
(b ond angles (bond angles
(bond angles
109.5°)
120°)
109.5°)
H
:
H
H-C-N-H
:
: :
: :
H
: :
H-C-C-H
H
HH
H
C N
H
H
Methyleneimine
(bond angles 120°)

3-D structure: Shows orientation in space,
using wedges and dashes.

Condensed structure: Bonds are not
specifically shown.

line-angle formula:
 A line
represents a carbon-carbon bond and a
vertex and a line terminus represent a carbon
atom.
 Hydrogen atoms are not shown in line-angle
formulas.
Ball-andstick model
Line-an gle
formula
Conden sed
structu ral
formula
CH3 CH2 CH3
Propan e
CH3 CH2 CH2 CH3
Butane
CH3 CH2 CH2 CH2 CH3
Pen tane

Constitutional isomers—compounds with
the same molecular formula, but with
different structural formulas (different
connectivity).
•
For the molecular formula C4H10, two
constitutional isomers are possible.
CH3 CH2 CH2 CH3
Bu tane
(bp -0.5°C)
CH3
CH3 CHCH3
2-Methylp ropan e
(bp -11.6°C)
Functional Groups

Functional group: an atom or group of
atoms within a molecule that shows a
characteristic set of predictable physical
and chemical properties.
Family
Functional
group
Example
Name
Alcohol
- OH
CH3 CH2 OH
Ethanol
Amine
- NH2
O
Ethanamine
Aldehyde
Carboxylic acid
- C- H
O
- CO
- C- OH
CH3 CH2 NH 2
O
CH3 CH
Carboxylic ester
O
- C- OR
Ketone
O
CH3 CCH3
O
CH3 COH
O
CH3 COCH 2 CH 3
Ethanal
Acetone
Acetic acid
Ethyl acetate

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
CH3 -C-OH
H
CH3 -C-OH
CH3
CH3 -C-OH
H
A 1° alcohol
CH3
A 2° alcohol
CH3
A 3° alcoh ol
H

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)
CH3 NCH3 or (CH3 ) 3 N
CH3
Trimethylamin e
(a 3° amine)
Carbonyl group: C=O
•
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)
RO R
O
R C-C-C R CH3 CCH3
R R
Functional
group
Acetone
(a ketone)

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 )

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
O
CH3 -C- O-CH 3 or CH3 COOCH3 or CH3 CO 2 CH 3
Methyl acetate
(an ester)
Summary of Topics: Chapter 1
What is Organic Chemistry?
 Structural formulas

 Lewis,
condensed, line-angle
Constitutional isomers
 Functional groups
