Chapter 22 Notes
ORGANIC CHEMISTRY is the study of covalently bonded
compounds that contain CARBON excluding carbonates
and oxides. Carbon has some unique characteristics that
allow for this branch of chemistry.



Carbon can bond to itself in long chains or rings.
This process is called CATENATION.
Carbon bonds readily with elements of similar electronegativity. These elements are hydrogen,
oxygen, nitrogen, and sulfur.
Compounds of carbon can have the same molecular formula and molar mass, but have different
structures. These structures are called ISOMERS.
Isomers exist in two forms. STRUCTURAL ISOMERS contain the same structural formula, but differ in
how the bonds are arranged.
Structural Form
Condensed form (Butane)
C4H10
Condensed form (Methyl –propane)
C4H10
These isomers will have different properties such as boiling points, melting points, density, etc.
CEOMETRIC ISOMERS are isomers where the order of bonding is the same, but the arrangement in
space is different.
CIS Dibromo- Ethene
TRANS Dibromo- Ethene
C2H2Br2
C2H2Br2
CIS indicates SAME
SIDE
TRANS indicates
OPPOSITE SIDE
C2H2Br2
C2H2Br2
Organic compounds containing only carbon and hydrogen are known as HYDROCARBONS. There are
two forms of hydrocarbons. A SATURATED HYDROCARBON refers to a hydrocarbon in which all carbon
atoms have 4 single covalent bonds. These hydrocarbons are called ALKANES (all single bonds).
Remember carbon can also form rings. A CYCLOALKANE is an alkane in which the carbon atoms are
arranged in a ring.
To name an alkane: (page 721 of textbook)
Find the longest continuous chain of carbon
atoms. Add the suffix –ane to the prefix
corresponding to the number of carbons in the
chain.
# of carbons
1
2
3
4
5
6
7
8
9
10
Prefix
methethpropbutpenthexheptoctnandec-
We learned in Chapter 6 that covalent bonds are not always single bonds. Multiple bonds are formed
when two or three pairs of electrons are shared. Hydrocarbons with double or triple bonds between
carbon atoms are called UNSATURATED HYDROCARBONS. These unsaturated hydrocarbons are
ALKENES (double bonds) or ALKYNES (triple bonds). The steps to naming these hydrocarbons are very
similar to alkanes. The same prefixes are
used to determine the number of
carbons, but steps are added to locate
the multiple bonds in the chain of
carbons.
Alkenes have double bonds. To name an
alkene: (page 725 of textbook)
Alkynes are named following the same steps as an alkene, but the bonds will include triple bonds. To
name an alkyne: (page 728 of textbook)
Hydrocarbons often have short chains of carbon that replace one or more of hydrogen atoms. These
short carbon chains attached to the long chain of carbons are known as ALKYL GROUPS. These must be
included in the naming of the hydrocarbon. They have been addressed in the naming guidelines in the
textbook. The diagram below shows how short chains of carbon can attach to the longer chain.
Lets name this compound!
1. HOW MANY CARBONS ARE IN THE LOGEST CHAIN?
5 carbons – use the prefix PENTA
2. ARE THE BONDS SINGLE, DOUBLE, OR TRIPLE BONDS?
Single bonds – use the suffix ANE
PENTANE
3. ARE THERE ALKYL GROUPS?
YES!
4. HOW MANY ALKYL GROUPS ARE THERE?
3 total alkyl groups
5. HOW MANY CARBONS ARE IN EACH OF ALKYL GROUP?
Each group has only one carbon so they are methyl groups. There are three of them so:
TRIMETHYL PENTANE
6. WHERE ARE THE ALKYL GROUPS?
1 methyl on the second carbon and 2 methyls on the third carbon
2, 3, 3 – TRIMETHYL PENTANE
The only real tricks to naming these types of hydrocarbons are the longest chain of carbons ais not
always a straight line. They will tend to bend. Counting carbons in regards to locating methyl groups
and bonds does always read from left to right. Sometimes you count from right to left.
Longest chain of
carbons
Start counting
with this carbon
3-Methyl 4-Ethyl Heptane
AROMATIC COMPOUNDS are hydrocarbons that have a 6 member carbon ring and delocalized electrons.
Delocalized electrons mean that you will see alternating double bonds. BENZENE is an aromatic
hydrocarbon as serves as the primary part of many more complex hydrocarbons.
The diagrams below all represent the formula for
benzene.
FUNCTIONAL GROUPS are atoms or groups of atoms that attach to a carbon of carbons and are
responsible for specific properties of the organic compound. These functional groups can be classified
into 8 basic types.
Alcohols
Organic molecules with a hydroxyl group (-OH) replacing
one or more hydrogen.
Methanol [CH3OH] and ethanol (beverage alcohol)
[CH3CH2OH] are common examples. Sugars are also
alcohols. Cold creams, lipsticks, body lotions, and other
similar products contain a common organic alcohol
called glycerol.
The general formula will be R-OH.
Alkyl Halide
Organic compounds where one or more halogens
replace one or more hydrogen. The general formula
is R – X, where X is fluorine, chlorine, bromine, or
iodine.
Ethers
Formed when two carbon atoms are linked by an
oxygen atom.
Diethyl ether is a commonly-used anesthetic.
Aldehydes
Contain a carbon atom to which is attached one hydrogen atom and — by a double bond —
one oxygen atom.
Formaldehyde [HCHO] is a powerful disinfectant and preservative (it denatures proteins).
Acetaldehyde is produced during the
conversion of acids to ethanol when
yeast ferment sugar. The converse is also
true — acetaldehyde is produced in the
liver as it metabolizes ingested ethanol
(and may be the prime culprit in a
"hangover").
Ketones
Organic molecules with a carbonyl group
(-C=O) between two hydrocarbon
portions.
Ketones are synthesized in the liver,
usually from fatty acids.
When glucose metabolism is suppressed,
during starvation or in diabetics, fatty
acids are used as a source of energy. But instead of entering the citric acid cycle, the acetyl-Coal
produced from them is converted into the ketone acetoacetate. Some of this is then converted
into acetone (which can be smelled on the breath of patients whose diabetes is out of control).
Both aldehydes and ketones are also responsible for many odors and flavors.
Amines
Organic molecules with an amino group, -NH2. These are generally produced
from the decay of amino acids.
Carboxylic Acids
Contain one or more carboxyl groups [COOH].
Many of the intermediates in the
breakdown of foodstuffs by cellular
respiration are carboxylic acids. Organic
acids are also used to give foods a sour
taste.
Esters
The removal of a molecule of water between the -OH
group of an alcohol and the -OH group of a carboxylic
acid. Esters, like aldehydes and ketone, are responsible
for many flavorings and odors. Multiple esters linked
together make a compound known as polyester.
Organic compounds undergo many of the same types of reactions discussed in Chapter 8.
Products of these reactions are polymers. POLYMERS are large molecules made of many small
units joined to each other through organic reactions. The smaller units are called MONOMERS.
These polymers can be made of identical or different monomers. These with multiple
monomers are called COPOLYMERS. These polymers can be found in the foods we eat to the
plastic containers the hold our food or the clothes we wear.