·
Organic compounds always contain carbon (C),
usually hydrogen (H), and may also have other non-metallic elements such as
oxygen (O), sulfur (S), nitrogen (N) or chlorine (Cl).
·
It must have four bonds and they will always
have an H3 at the end.
·
Many organic compounds burn vigorously in air.
Typically, organic compounds are not soluble in water.
·
Inorganic compounds are ionic, which leads to
high melting and boiling points. Inorganic compounds that are ionic or polar
covalent are usually soluble in water.
·
Most organic substances so not burn in air.
·
Hydrocarbons are organic compounds that consist
only of carbon and hydrogen. The simplest hydrocarbon is methane, CH4.
·
A molecule with four atoms bonded to a central
atom has a tetrahedral shape.
·
More than 90% of the compounds in the world are
organic compounds. The large number of carbon compounds is possible because the
covalent bond between carbon atoms is very strong, allowing carbons to form
long, stable chains.
·
The alkanes are a class of hydrocarbons in which
they are connected by only single bonds. One of the most common uses is fuels.
·
Alkane prefixes:
1.
Methane CH4
2.
Ethane C2H6 CH3-CH3
3.
Propane C3H8
4.
Butane C4H10
5.
Pentane C5H12
6.
Hexane C6H14
7.
Heptane C7H16
8.
Octane C8H18
9.
Nonane C9H20
10.
Decane C10H22
·
In a condensed structural formula, each carbon
atom and its attached hydrogen atoms are written as a group. A subscript
indicates the number of hydrogen atoms bonded to each carbon atom.
·
The bonds can rotate freely about connecting the
carbon atoms.
·
Hydrocarbons can also form cyclic structures
called cycloalkanes, which have two fewer hydrogen atoms than the corresponding
alkanes.
·
Cyclo always has two compounds less,
the H2 is connected on each side, it’s not a straight line. When it
cyclizes, it loses 2H atoms.
·
cyclopropane cyclobutane
cyclopentane cyclohexane
·
When an alkane has four or more carbon atoms,
the atoms can be arranged so that a side group called a branch or substituent
is attached to a carbon. An alkane with at least one branch is called a
branched alkane.
·
When two compounds have the same molecular
formula but different arrangements of atoms, they are called isomers.
·
The carbon branch is named as an alkyl group,
which is an alkane that is missing one hydrogen atom.
o
CH3 = Methyl
o
CH3-- CH2 = Ethyl
o
CH3-- CH2--CH2 =
Propyl
o
F--, Cl--, Br--, I--, Fluoro, chloro, bromo,
iodo
 |
o
CH3—CH—CH3 = Isopropyl
·
How to write the alkanes with substituents
1.
Write the name of the longest chain
2.
Number the carbon atoms starting from the end
nearest a substituent (stay in that direction once you start numbering)
3.
Give the location and name of each substituent
as a prefix to the alkane name
4.
If there are more than one substituent, call
them di, tri, or tetra as appropriate
5.
No number is necessary for a compound with one
or two carbon atoms and one substituent
·
To figure out if the chain is an isomer or the
same molecule, count the carbons and hydrogens. If they’re the same, just
rearranged, they’re isomers. If they’re the same but not rearranged, just
flipped around, they’re the same molecule.
·
Many types of alkanes are the components of
fuels that power our cars and oil that heats our homes.
·
Alkanes are nonpolar, which makes them insoluble
in water. However, they are soluble in nonpolar solvents such as other alkanes.
·
The first four alkanes- methane, ethane,
propane, and butane- are gases at room temperature and are widely used as
heating fuels.
·
Alkanes having five to eight carbon atoms
–pentane, hexane, heptanes, and octane- are liquids at room temperature and are
highly volatile, which make them useful fuels such as gasoline.
·
Liquid alkanes with nine to seventeen carbon
atoms have higher boiling points and are found in kerosene, diesel, and jet
fuels.
·
An alkane undergoes combustion when it
completely reacts with oxygen to produce carbon dioxide, water, and energy.
Carbon-carbon single bonds are difficult to break, which makes alkanes the
least reactive family of organic compounds. Alkanes burn readily in oxygen.
·
In organic compounds, carbon atoms are most
likely to bond with hydrogen, oxygen, nitrogen, sulfur, and halogens.
·
Within this vast number of compounds, there are
specific groups of atoms called functional groups that give compounds similar
properties.
·
The alkenes contain one or more double bonds
between carbon atoms.
·
Alkynes contain triple bonds.
·
Aromatic compounds contain benzene, a molecule
that has a ring of six carbon atoms with one hydrogen atom attached to each
carbon.
·
The characteristic functional group in alcohols is
the hydroxyl (-OH) group bonded to a carbon atom.
·
In thiols, the functional group –SH is bonded to
a carbon atom.
·
In ethers, the feature is an oxygen atom bonded
to two carbon atoms.
·
Aldehydes and ketones contain a carbonyl group
(C=O), which is a carbon with a double bond to oxygen.
·
In an aldehyde, the carbon atom of the carbonyl
group is bonded to another carbon and one hydrogen atom. It’s always at the
end.
·
In a ketone, the carbonyl group is bonded to two
other carbon atoms.
·
In carboxylic acids, the functional group is the
carboxyl group, which is a combination of the carbonyl and hydroxyl groups.
·
An ester is similar to carboxylic acid, except
that the oxygen of the carboxyl group is attached to a carbon and not to
hydrogen.
·
In amines, the central atom is a nitrogen atom.
Amines are a derivative of ammonia, NH#, in which carbon atoms replace one,
two, or three of the hydrogen atoms.
·
An amide, the hydroxyl group of a carboxylic
acid is replaced by a nitrogen group.
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