prelim org chem lesson 1 Flashcards
a compound composed of only carbon and hydrogen.
hydrocarbon
only carbon single bonds
alkanes
one or more carbon carbon;double bonds
alkenes
one or more carbon;triple bonds
alkynes
one or more benzene like rings
benzene
A line represents a carbon-carbon bond and a vertex and a line terminus represent a carbon atom.
line-angle formula
are not shown in line-angle formulas.
Hydrogen atoms
compounds that have the same molecular formula but different structural formulas (different connectivity).
Constitutional isomers:
only one structural formula is possible; there are no constitutional isomers for these molecular formulas.
the molecular formulas CH4, C2H6, and C3H8
two constitutional isomers are possible.
the molecular formula C4H10
the number of carbon atoms in the chain.
a prefix
shows that the compound is a saturated hydrocarbon.
the suffix -ane:
the longest chain of carbon atoms
a parent name`
the groups bonded to the parent chain
substituent names
a substituent group derived from an alkane by removal of a hydrogen atom.
Alkyl group
commonly represented by the symbol R-.
Alkyl group
named by dropping the -ane from the name of the parent alkane and adding the suffix -yl.
Alkyl group
consists of a prefix showing the number of carbon atoms and the ending -ane.
alkane
rules to remember in IUPAC NAME
Do not include the prefixes di-, tri-, tetra-, and so on, or the hyphenated prefixes sec- and tert- in alphabetizing;
alphabetize the names of substituents first, and then insert these prefixes
If there is one substituent, number the parent chain from the end that gives the substituent the lower number.
If the same substituent occurs more than once:
Number the parent chain from the end that gives the lower number to the substituent encountered first.
Indicate the number of times the substituent occurs by a prefix di-, tri-, tetra-, penta-, hexa-, and so on.
Use a comma to separate position numbers.
The first three alkanes
methane, ethane, and propane.
shows that one end of an otherwise unbranched chain terminates
iso
a hydrocarbon that contains carbon atoms joined to form a ring.
Cyclic hydrocarbon
a cyclic hydrocarbon in which all carbons of the ring are saturated.
Cycloalkane
ring sizes ranging from 3 to over 30 carbon atoms are found in nature.
Cycloalkanes
are especially abundant in nature.
Five-membered (cyclopentane) and six-membered (cyclohexane) rings
rules to remember for cycloalkanes
If there is only one substituent on the ring, there is no need to give it a location number.
If there are two substituents, number the ring beginning with the substituent of lower alphabetical order.
three-dimensional arrangement of atoms in a molecule that results by rotation about a single bond.
Conformation
The most stable conformation of a cyclopentane ring is an
envelope conformation
The most stable conformation of a cyclohexane ring is the
chair conformationn
all bond angles are approximately
109.5°
six C-H bonds are
equatorial and axial
on the same side
cis
across from
trans
Because cis-trans isomers differ in the orientation of their atoms in space, they are
stereoisomers
In Ch 15, we study another type called
enantiomers
Cis-trans isomers are one type of
stereoisomer
The electronegativity difference between carbon and hydrogen is 2.5 - 2.1 =
0.4 on the Pauling scale
are nonpolar compounds and the only interaction between their molecules are the very weak London dispersion forces.
alkanes
lower than those of almost any other type of compound of the same molecular weight.
Boiling points of alkanes
are not soluble in water; they are unable to form hydrogen bonds with water.
Alkanes
are soluble in each other.
Alkanes
are also soluble in other nonpolar organic compounds, such as toluene and diethyl ether.
Alkanes
is the basis for their use as energy sources for heat [natural gas, liquefied petroleum gas (LPG), and fuel oil] and power (gasoline, diesel fuel, and aviation fuel).
oxidation
Halogenation of an alkane is
Halogenation of an alkane
manufactured under the trade name Freon
Chlorofluorocarbons (CFCs)
are nontoxic, nonflammable, odorless, and noncorrosive.
Chlorofluorocarbons (CFCs)
CFCs were used as;
heat-transfer agents in refrigeration systems.
industrial cleaning solvents to prepare surfaces for coatings and to remove cutting oils from millings.
propellants for aerosol sprays.
cause destruction of the Earth’s stratospheric ozone layer.
cause destruction of the Earth’s stratospheric ozone layer.
The most prominent replacements are the
hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons (HCFCs)
These compounds are chemically more reactive than CFCs and are destroyed before they reach the stratosphere.
hydrochlorofluorocarbons (HCFCs)
90 to 95 percent methane
Natural gas
5 to 10 percent ethane
Natural gas
a mixture of other relatively low-boiling alkanes, chiefly propane, butane, and 2-methylpropane.
Natural gas
A thick, viscous liquid mixture of thousands of compounds, most of them hydrocarbons formed from the decomposition of marine plants and animals.
Petroleum
1 carbon=
2carbon=
3carbon=
4carbon=
5carbon=
6carbon=
7carbon=
8carbon=
9carbon=
10carbon=
methane
ethane
propane
butane
pentane
hexane
heptane
octane
nonane
decane
