2. Organic - pertaining to
life Living or was once
living Organic Chemistry -
The chemistry of carbon
compounds Carbon is well
suited for life because it is
the most versatile element
in terms of bonding.
3. Carbon (C) appears in the 2nd row of the
.
periodic table and has atomic number of 6. Given
our discussion of electron shells it is easy to see
that carbon has 4 electrons in its valence shell.
Since carbon needs 8 electrons to fill its valence
shell, it forms 4 bonds with other atoms (each
bond consisting of one of carbon's electrons and
one of the bonding atom's). Every valence
electron participates
in bonding, thus a carbon atom's bonds will be
distributed evenly over the atom's surface. These
bonds form a tetrahedron, as illustrated below :
4. Carbon can form four bonds.
They can be single, double or triple
bonds.
Carbon will not form diatomic
molecules like other small atoms
do.
It can form long carbon chains
containing strong, short, covalent
bonds.
5. Allotropes forms of the same element
that differ in their bonding There are
several allotropes of carbon
Diamond – tetrahedral network of
carbon atoms (every atom is locked
into place (hardness)
Graphite – sheets can slide over each
other (lubricant)
6.
7. Amorphous carbon charcoal, soot,
coke Amorphous has not set
arrangement of atoms. It has irregular
patterns of high surface area, deep
“caves” that can trap other molecules
Fullerenes – spherical molecules (60
atoms) see page 807, mostly
experimental at this point.
9. Fossil Fuels
Natural gas - mostly methane
Crude oil - mixture of hydrocarbon chains
from propane to butane, octane and
longer Components separated using
fractional distillation (see page 823)
Coal - mostly impure carbon (coke - pure
carbon from coal, charcoal - pure carbon
from wood)
10. Types of Formulas
(examples)
Compound – hexane
.Empirical formula
. Molecular formula
.Structural formula
.Condensed structural
formula
11. CLASSIFICATION OF ORGANIC COMPOUNDS
ALKANES - Compounds that contain
only hydrogen and single bonded
carbons. (carbon chains surrounded
by hydrogens).
Named with an ane ending that is
preceded with a prefix which gives
how many carbons that are in the
carbon chain.
12. An organic molecule (hydrocarbon) is
formed when carbon bonds to
hydrogen. The simplest hydrocarbon
consists of 4 hydrogen atoms bonded
to a carbon atom (called methane):
Methane
13. In addition to binding to hydrogen, carbon can
also bind to other carbon atoms, as illustrated
below:
In fact the uniqueness of carbon comes from the
fact that it can bind to itself. Carbon atoms can
form long chains:
branched chains:
Ethane Hexane
15. Saturated vs Unsaturated Hydrocarbons
Saturated carbons are single bonded and
have a greater compliment of hydrogen.
( hence, saturated )
Unsaturated carbons are generally doubled
bonded and thus are attached to fewer
hydrogen.
16. In fact, there appears to be almost no limit to the number of different structures that
carbon can form. To add to the complexity of organic chemistry, neighboring carbon
atoms can form double and triple bonds in addition to single carbon-carbon bonds:
Single, double, and triple bonds :
Keep in mind that each carbon atom forms 4 bonds. As you increase the number of
bonds between carbon atoms, the number of hydrogen atoms in the molecule
decreases.
17. . Nomenclature (naming compounds):
The simplest hydrocarbons are those that contain only
carbon and hydrogen. As we have seen, these come in
three varieties: 1) alkanes, molecules with only single
bonds, 2) alkenes, those with one or more double bond
and 3) alkynes, those with one or more triple bond.
Basic organic chemistry can be thought of as a molecular
Erector Set, if you know the number of carbon atoms
and the type of bonds in a molecule, you can build the
molecular structure
18. To describe the number of carbon atoms in a hydrocarbon, chemists use prefixes in the
molecule's name. The first 10 prefixes used in organic chemistry are shown below. To
complete the hydrocarbon name, the prefix is attached to the ending of the root word
(drop the alk- from the words alkane, alkene or alkyne) to describe the type of bonding
on the molecule.
Hydrocarbon prefix
# of C atoms name formula structure
Meth 1 methane CH4 Eth 2 ethane C2H6 Prop 3 propane C3H6
19. Hydrocarbon prefix # of C atoms name formula structure
but 4 butane C4H10
pent 5 pentane C5H12
hex 6 hexane C6H14
hept 7 heptane C7H16
oct 8 octane C8H18
non 9 nonane C9H20
dec 10 decane C10H22
20. 14. Alkanes (Single Bonds)
As we have discussed, each carbon atom has 4 bonds.
As you add carbon to a molecule, the empty carbon
bonds are filled with hydrogen atoms (or other elements,
as we will soon see). You can calculate the number of H
atoms in the simple alkanes. The number of H atoms in
a simple alkane equals two times the number of carbon
atoms plus 2, or (2n + 2), where n is the number of
carbon atoms in the molecule.
21. Alkenes (double bonds)
The simple alkenes have 1 double bond and 2
fewer H atoms in the molecule; the number of H
atoms in the simple alkenes = (2n). Simple
alkynes contain 1 triple bond 2 fewer H atoms
than the alkene, or (2n - 2) H atoms.
22. Functional Groups In addition to carbon and
hydrogen, hydrocarbons can also contain
other elements. The alcohols, for example,
are a group of hydrocarbons in which a
hydroxol (-OH) group is bound to a carbon
skeleton.
23. These compounds are named like the simple
hydrocarbons, a prefix attached to a root ending (-anol
for the alcohols). Thus ethanol, is a 2 carbon alcohol with
the structure:
Most people are familiar with this organic compound as
it is the active ingredient in "alcoholic" beverages such as
beer and wine.
24. . While the simple hydrocarbons are important, they do not themselves commonly occur
in living organisms (except for during the occasional bout of methane flatulence).
25. . The simple hydrocarbons are the building blocks of more complex molecules that
make up living organisms. In the next few weeks, I will introduce some of these
molecules and their biochemistry, the chemistry of life. Alcohol (Hydroxyl Group)
Aldehyde (Carbonyl Group) Ketone (Carbonyl Group) Carboxylic Acid (Carboxyl
Group) Amine (Amino Group) Amino Acid (Amino Group + Carboxyl Group)
26. Great site that helps to match the funtional group to it’s structure.
http://biology.clc.uc.edu/courses/bio104/carbon.htm Many important organic
chemistry molecules contain oxygen or nitrogen. It's a good idea to memorize the names
and structures of these functional groups.
27. . ALKANES SUBSTITUDED WITH
HALOGENS Give the position of the
halogen (F, Cl, Br, or I) and then give the
name of the halogen with an "o" ending. 3-
chloro-2-methylpentane
bromochloroiodomethane
28. .Conformational isomers - molecules with the
same structure but with different bond rotation.
Molecules with single bonds can rotate about the
single bond. These are the same compound. They
have the same melting point, the same boiling
points and the same chemistry. The higher the
temperature the faster they change back and
forth from one form to the other. Example:
cyclohexane (chair and boat conformation)
29. Structural isomers - molecules that have the
same molecular formula but have different
structural formulas. These are different
compounds with different melting points
and different chemistry Examples C5H12
(pentane, 1 methyl butane, 2,2 dimethyl
propane)
30. SUBSTITUTED ALKANES Fisher Projection - a
way to show the 3-dementional character of a
molecule. Examples: CHFClI A carbon that has 4
different groups bonded to it is called a chiral
carbon. Enantiomers - (mirror image isomers) -
two arrangements around a chiral carbon that
cannot be rotated in such a way as to be
superimposed on each other.
31. They are different molecules that have the
same formula, same boiling points and
much of the same chemistry. Their
chemistry differs when they are reacting
with molecules that also have chiral
carbons. (biological systems) They also
rotate polarized light in opposite directions.
Vitamin C is an example of this type of
molecule
32. . UNSATURATED HYDROCARBONS If
the molecule is filled to capacity with
hydrogen the compound is saturated
(alkanes). If the molecule is cyclic, contains
a double bond or contains a triple bond it is
unsaturated. Saturated fats are from
animals and are not good for you.
Unsaturated fats are from plants