Download World of Chemistry Chapter 20—Organic Chemistry

World of Chemistry Chapter 20—Organic Chemistry
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Definition: Organic chemistry is the study of carbon-containing
compounds and their properties.
Overview: Polymers (long chain-like molecules) and other organic
compounds have changed the world. Nylon, Velcro, Kevlar and
other polymers are used every day. This is made possible by 2
group 4 elements: Carbon and silicon.
I.
Section 20.1—Carbon bonding
A. There are several million known carbon-chain (organic)
molecules which are the basis for respiration and
reproduction in all plants and animals.
B. Carbon forms strong bonds to itself and to many
other elements
C. More than any other element, carbon can form long
chains of molecules
II. Section 20.2—Alkanes
A. Alkanes are saturated hydrocarbons—which means
that they are a chain of carbon and hydrogen atoms
where each carbon atom is bound to 4 other atoms
with no double or triple bonds
B. The simplest alkane is methane—CH4
C. All alkanes can be represented by the general
formula: CnH2n+2
III. Section 20.3—Isomerism and Structural Formulas
A. An isomer is a molecule with the same formula but
different arrangement as its parent molecule
B. Different isomers have different properties due to
their different arrangements
IV. Section 20.4—Naming Alkanes
A. Rules for naming alkanes
Rules for Naming Alkanes
1. Find the longest continuous chain of carbon atoms. This chain
(called the parent chain) determines the base alkane name.
2. Number the carbons in the parent chain, starting at the end
closest to any branching (the first alkyl substituent). When a
substituent occurs the same number of carbons from each end,
use the next substituent (if any) to determine from which end
to start numbering.
3. Using the appropriate name for each alkyl group, specify its
position on the parent chain with a number.
4. When a given type of alkyl group occurs more than once,
attach the appropriate prefix to the alkyl name.
5. The alkyl groups are listed in alphabetical order, disregarding
any prefix
V.
VI.
Section 20.5—Petroleum
A. Petroleum is a thick, dark liquid composed largely of
hydrocarbons containing from 5 to over 25 carbon
atoms (also known as “crude oil”.)
B. Natural gas (which is found with petroleum deposits)
contains mostly methane as well as significant
amounts of ethane, propane and butane.
C. Petroleum probably formed from the remains of
marine organisms that lived about 500 million years
ago.
D. When petroleum and natural gas are burned they
release energy that originally came from the
sun…photosynthesis stored energy in the plants and
by burning their decay products we can release that
energy. These are fossil fuels
Section 20.6—Reactions of Alkanes
A. At high temperatures alkanes react vigorously with
oxygen…these are combustion reactions
B. Substitution reactions occur when one or more
hydrogen atoms are replaced by different atoms
Example: CH4 + Cl2  CH3Cl+ HCl
C. Dehydrogenation reactions occur when a hydrogen
atom is removed and a double bond is formed
VII. Section 20.7—Alkenes and Alkynes
A. Alkanes are saturated hydrocarbons (each carbon
atom is bonded to 4 other atoms by single bonds)
B. Alkenes are unsaturated hydrocarbons where a
hydrogen atom is removed and a double bond forms
C. Alkynes are unsaturated hydrocarbons where a
hydrogen atom is removed and a triple bond forms
Rules for Naming Alkenes and Alkynes
1. Select the longest continuous chain of carbon atoms that
contains the double or triple bond.
2. For an alkene, the root name of the carbon chain is the same
as the alkane except that the –ane ending is replaced by –ene.
For an alkyne, the –ane is replaced by –yne.
3. Number the parent chain, starting at the end closest to the
double or triple bond. The location of the multiple bond is
given by the lowest-numbered carbon involved in the bond.
4. Substituents on the parent chain are treated the same way as
in naming alkanes.
D. Reactions of alkenes
1. addition reactions=new atoms form single bonds
to the carbons formerly involved in multiple
bonds
2. hydrogenation reactions=replaces multiple
bonds with hydrogen atoms
3. halogenation reactions=replaces multiple bonds
with halogen atoms
4. polymerization reactions=many small molecules
are joined together to form a large molecule.
VIII.Section 20.8—Aromatic Hydrocarbons
A. Wintergreen, cinnamon and vanilla are all aromatic
hydrocarbons.
B. Aromatic hydrocarbons all have a six-carbon atom
structure called a “benzene ring”.
IX.
X.
Section 20.9--Naming Aromatic Compounds
A. Monosubstituted Benzenes (formed when one of the
hydrogen atoms on the ring is replaced) are named by
adding the substituent name as a prefix to “benzene”.
B. Disubstituted Benzenes (formed when more than one
hydrogen atom on the ring is replaced) are named by 2
different methods described on pp.656-7
Section 20.10—Functional Groups
A. Definition: A Functional Group is an atom or group of
atoms that are added to a hydrocarbon chain.
B. Functional groups include:
1. Halohydrocarbons
2. Alcohols
3. Ethers
XI.
4. Aldehydes
5. Ketones
6. Carboxylic Acids
7. Esters
8. Amines
C. Rules for naming the functional groups are found on
pp.660-670 (Sec. 20.11-20.15)
Polymers
A. Polymers are large, chain-like molecules that are built
from smaller molecules called monomers.
B. Plastics (like polyethylene) are polymers and can be
very versatile.
C. Teflon, vinyl, Dacron (a polyester), styrene and nylon
are all common polymers.