The study of carbon-based compounds
and their properties.
Historically the distinction between
inorganic and organic substances was
based on whether or not they were
produced by living systems. It was
believed that some sort of “life force”
was needed to synthesize them.
NH4OCN  H2N—C—NH2
O
urea
In 1828, the German chemist Freidrich Wohler
(1800-1882) prepared urea from the inorganic
salt ammonium cyanate by simple heating.
Hydrocarbons:
contain only hydrogen and carbon
Hydrocarbons can be divided into different
types, depending on their bonding.
Hydrocarbons
Aliphatic
Aromatic
Alkanes Alkenes Alkynes Cyclic
Naming Organic Molecules
Alkanes - - Carbon chain, no double
or triple bonds. All single bonds
(saturated)
Alkenes - - Carbon chain, contains
double bond(s) (unsaturated)
Alkynes - - Carbon chain, contains
triple bond(s) (unsaturated)
Naming Organic Molecules
There are two parts to the main name
of each molecule…
prefix: tells the
# of carbons in
main chain or ring
suffix: tells the
type of bonding in
the chain or ring
Prefix: indicates number of carbon
atoms in the main chain or ring
1 meth-
6 hex-
2 eth-
7 hept-
3 prop-
8 oct-
4 but-
9 non-
5 pent-
10dec-
Suffix: indicates types of bonds present
Alkanes: (all single bonds) ___ -ane
Alkenes: (double bond)
___ -ene
Alkyne: (triple bond)
___ -yne
Saturated Hydrocarbons:
 the
ALKANES: chains of carbon
connected by single bonds:

contain only single C-C bonds
Saturated v. Unsaturated fats
Saturated
with H
Single bonds
are free to
rotate, so
these fats
can pack
tightly
(solid @
room temp)
Which one is saturated?
ALKANES
ALKANES
ALKANES
propane, C3H8
ALKANES
butane, C4H10
ALKANES
pentane, C5H12
ALKANES
hexane, C6H14
ALKANES
octane, C8H18
Don’t write this example down, but watch to see
where we’re going with this…
(Although you will be required to include the H’s if you take IB Chemistry)
“Normal” v. Branched
 “normal”
hydrocarbons are straight
chains; no branching
 Branched-chain
hydrocarbons – isomers
of “normal” hydrocarbons; have same
formula, but different structures
n-butane
2-methlypropane
n-pentane
2-methylbutane
Are there any other pentane isomers?
Another branched alkane:
2,2-dimethylpentane
Cycloalkanes
cyclopentane
Cycloalkanes

cyclobutane
Cycloalkanes
1 -ethyl- 3 -methylcyclopentane
 ________________________
methyl3
1
green or red?
22
1
3
ethyl-
Unsaturated Hydrocarbons:
ALKENES – contain C-C double bonds
2-pentene
Unsaturated Hydrocarbons:
ALKENES – contain C-C double bonds
2,4-hexadiene
Unsaturated Hydrocarbons:
ALKYNES – contain C-C triple bonds
1-butyne
Unsaturated Hydrocarbons:
ALKYNES – contain C-C triple bonds
3-ethyl-1-pentyne
Aromatic Hydrocarbons:
benzene – the simplest aromatic
hydrocarbon; has a symmetrical ring
structure
Aromatic Hydrocarbons:
benzene – can be drawn like this…
Derivatives of benzene:
1-ethyl-2-methylbenzene
Derivatives of benzene:
1,2-dimethyl-4-propylbenzene
For your homework:
If a halogen is attached, use the
following prefixes:
fluorochlorobromoiodo(instead of methyl-, ethyl-, propyl-, etc.)