Transcript Chapters 20 & 21

Chapters 20 & 21
Carbon and Hydrocarbons
&
Other Organic Compounds
Sect. 20-2: Organic Compounds
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Organic compound – covalently bonded
compounds containing carbon (except
carbonates and oxides)
Catenation – covalent binding of an element to
itself to form chains or rings
Hydrocarbons – simplest organic compounds
containing only carbon and hydrogen
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Structural formula – indicates the number and
types of atoms present in a molecule and also
shows the bonding arrangement of the atoms
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Condensed structural formula
Isomers – compounds that have the same
molecular formula but different structures
2 types of isomers
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Structural isomers – isomers in which the atoms
are bonded together in different orders
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Example: butane and 2-methylpropane
Geometric isomers – isomers in which the order
of atom bonding is the same, but the
arrangement of atoms in space is different
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Example: 1,2-dichloroethene
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In order for geometric isomers to exist:
There must be a rigid structure to prevent free
rotation around a bond
 2 carbons must have at least 2 different groups
attached to them
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Arrangements have different names, cis and trans
cis – same side of the molecule
 trans – different side of the molecule
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Sect. 20-3: Saturated Hydrocarbons
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Saturated hydrocarbon – carbons form 4 single
covalent bonds with other atoms
Alkane – hydrocarbon that contains only single
bonds
Homologous series – a series in which adjacent
members differ by a constant unit (in the case of
alkanes it is 1 C and 2 H)
 General formula is CnH2n+2
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Cycloalkane – alkane in which the carbon atoms
are arranged in a ring structure
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Have 2 fewer hydrogens than the straight chain with
the same number of carbons
Naming rules
1.
For a straight-chain alkane, use a prefix telling
how many carbons followed by –ane.
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1 – meth6 – hex2 – eth7 – hept3 – prop8 – oct4 – but9 – non5 – pent10 – decExample a 5 carbon straight chain would be
pentane
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Alkyl groups are named by the same prefix as
alkanes, but with –yl suffix
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Alkyl group – groups of atoms that are formed
when a hydrogen is removed from an alkane
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Attached to “parent chain” to make a branched chain
alkane
Names of alkyl groups are placed in front of the
parent chain name and use prefixes (di, tri, tetra to
tell how many of each alkyl group are attached)
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If multiple alkyl groups exist, list in alpha
order
Number the carbons of the parent chain in
such a way that the alkyl groups are on the
lowest # carbon
Include the number carbon that each alkyl
group is attached to in the name
Separate numbers with commas and numbers
from words with dashes
7.
When naming a cycloalkane, use the same
rules, except add the prefix cyclo- in front of
the parent ring name
Sect. 20-4: Unsaturated
Hydrocarbons
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Unsaturated hydrocarbons – hydrocarbon in
which some carbons have double or triple bonds
Alkene – hydrocarbon containing at least one
double bond
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General formula is CnH2n
Alkyne – hydrocarbon containing at least one
triple bond
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General formula is CnH2n-2
Rules for multiple bonds
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All alkane naming rules apply for alkene and alkyne
naming with a few exceptions/additions:
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The parent chain is the longest carbon chain that contains the
multiple bond
Instead of –ane suffix, use –ene for double bond and –yne
for triple bond
If there is more than one double or triple bond, use di or tri
just before the suffix to indicate how many double/triple
bonds
Carbons should be numbered so that the multiple bond has
the lowest number possible & the number of the carbon
attached to the multiple bond is indicated just before the
parent chain’s name (ex: 1-pentene)
Chapter 21
Sect. 21-1&2: Functional Groups and
Classes of Organic Compounds
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Functional group – an atom or group of atoms that is
responsible for the specific properties of an organic
compound
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Alcohols
Alkyl halides
Ethers
Aldehydes
Ketones
Carboxylic acids
Esters
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Alcohol – organic compounds that contain one
or more hydroxyl groups
Naming alcohols:
The parent chain must contain the hydroxyl group;
# so it has lowest #
 Replace the final –e in the name with –ol or if more
than one hydroxyl group, use the whole name and
then diol (2) or triol (3), etc.
 Indicate which # carbon the hydroxyl group is
attached
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Alkyl halides – organic compounds in which one or
more halogen atoms (F, Cl, Br, or I) are substituted for
one or more hydrogen atoms
Naming alkyl halides:
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Parent chain must include halide
Add prefix indicating which halide is attached and if
necessary, add prefix to indicate how many
Indicate the # carbon to which the halide is attached
Ethers – organic compound in which two hydrocarbon
groups are bonded to the same atom of oxygen
Naming ethers
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The word ether will come at the end of the name
List the alkyl groups in alpha order in front of “ether” and
use di if they are the same and put spaces between each word
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Aldehyde – organic compound in which the
carbonyl group is attached to a carbon atom at
the end of a carbon chain
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To name, change the end –e to -al
Ketone – organic compound in which the
carbonyl group is attached to a carbon atom
within the chain
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To name, chage the end –e to –one and identify
which carbon the ketone is attached to
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Carboxylic acid – an organic compound that contains
the carboxyl functional group
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To name, change end –e to –oic acid; if more than one use
dioic acid (2) or trioic acid (3), etc.
Ester – an organic compound with carboxylic acid
group in which the hydrogen of the hydroxyl group has
been replaced by an alkyl group
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To name, name the carboxylic acid that it was formed from
and then change the –oic acid to –oate
Name the alkyl group that replaced the hydrogen & add to
front of name