Alkanes and Cycloalkanes Flashcards
saturated hydrocarbons whose atoms are arranged in an open chain
alkanes
alkanes are commonly reffered to as
aliphatic hydrocarbons
alkanes are the __ and __ __ hydrocarbon
- simplest
- least reactive
Classifications of alkanes
- Acyclic (linear, branched)
- Cycloalkanes
General formula of alkanes
CnH2n+2
first two members of teh alkane family
- methane (CH4)
- ethane (C2H6)
alkanes are arranged in what manner
tetrahedral
angles between alkanes
109.5 angles
Ways in showing the structural formula of alkanes
- Molecular formula
- Complete structural formula
- Condensed structural formula
- Line-angle formula
alkane with one or more alkyl groups
branched-chain alkanes
General formula of alkyl groups
CnH2n+1
an atom or groups of atoms that took the place of a hydrogen atom on a parent hydrocarbon molecule
substituent
longest continuous chain of branched-chain hydrocarbons
parent alkane
hydrocarbon whose atoms joined together to form a saturated ring
cycloalkanes
most abundant cycloalkanes
- cyclopentane
- cyclohexane
General formula of cycloalkanes
CnH2n
IUPAC
International Union of Pure and Applied Chemistry (IUPAC)
a system on which most organix chemists have agreed to provide guidlie to allow them to learn from eah others’ works
nomenclature
indicated the number of carbon atoms in the chain
prefix
show that the compopund is a saturated hydrocarbon
Suffix -ane
general name of saturated hydrocarbon
alkane
hyphenated prefixes, such as __ and __, are not considered when alphabetizing
- sec-
- tert-
not a hyphenated prefix and is included when alphabetizing
iso-
group derived from removing a hydrogen from an alkane
alkyl group
symbol used to represent an alkyl group
R-
A + B –> A–B
synthesis
A–B –> A + B
decomposition
A–B + C –> A–C + B
single replacement
A–B + C–D –> A–D + C–B
double replacement
the temperature at which a given solid will melt, and a liquid boils and turns to vapor
melting and boiling point
the abbility to be dissolved, especially in water
solubility
the degree of compactess of a substance
density
Increases if there is an increase in no. of carbon atoms
boiling point
lowers the boiling point of an alkane
branching in carbon chain
have higher boiling point than their acyclic counterparts
cycloalkanes
__ __ have higher boiling and melting point than __ __ __
- longer straight-chained
- shorter straight chained alkanes
more branches, then molecule becomes more compact
have weaker Van der Waals because surface area in contact are reduced
cyclic molecules can get close together because the ring structure makes them
- tidier
- less wriggly
closer molecules means
strong intermolecular forces
cycloalknaes has __ __ __ than that of corresponding straight chain alkanes
higher boiing point
alkanes are insoluble in __ solvents such as __
polar solvents
water
alkanes are unable to form __ __ with water
hydrogen bond
alkanes are soluble in __ solvents
non-polar
examples of non-polar solvents alkanes are soluble with
- toluene
- benzene
- carbon tetrachloride
- chloroform
alkanes are lighter or less dense than __
water
densities of alkanes and cycloalkanes ranges from __ - __ g/mL
0.6-0.8 g/mL
density of water
1.0 g/mL
density of alkanes increases with increasing __ __
molecular weight
Reactions of Alkanes
- Combustion
- Halogenation
two types of combustion in alkanes
- Complete combustion
- Incomplete combustion
- happens when oxygen has a plentiful supply
- carbon and hydrogen atoms react with oxygen in an exothermic reaction
- carbon dioxide and water are produced
- maximum energy is given out
complete combustion
in complete combustion, carbon and hydrogen atoms react with oxygen in an __ reaction
exothermic
what are produced in complete combustions
carbon dioxide
water
in complete combustion, __ energy is given out
maximum
general formula for complete combustion of alkanes
hydrogen + oxygen –> carbon dioxide + water
- happens when oxygen only has a limited supply
- impure carbon particles (soot), carbon monoxide, and water are produced
- less energy is released
incomplete combuston
what are produced in incomplete combustions
- carbon particles (soot)
- carbon monoxide
- water
in incomplete combustion, __ energy is given out
less
produces hydrocarbon derivatives in which one or more halogen atoms have replaced hydrogen atoms
halogenation
where does halogenation happen
to halogen with alkane in the presence of ultaviolet (UV) light
halogenation leads to the formation of __
haloalkane (aka alkyl halide)
halogenation is an example of a __ __
substitution reaction
three phase radical substitution reaction
- initiation
- propagation
- termination
initiation
non radical –> radical
propagation
radical –> radical
termination
radical –> non radical
type of reaction that happens to halogens with cycloalkanes in the presence of UV light
substitution reaction
type of reaction that happens to halogens with cycloalkanes without UV light
addition reaction
two types of reactions of cycloalkanes
- halogenation
- hydrogenation
cycloalkanes undergo hydrogenation to produce __ __
saturated carbons
when the ring size of cycloalkanes gets bigger, the hydrocarbon becomes __ to hydrogenation
resistant
how many carbons does it take for hydrogenation to less likely occur
6 or more carbons
hydrogenation of cycloalkanes occurs in the presence of catalysts such as
- Nickel
- Platinum
application of alkanes and cycloalkanes
- transportation fuel
- consumer products (paint, varnish remover)
- heat generating products
class of organic compound containing only hydrogen and carbons
hydrocarbons
contains only single bonds
saturated hydrocarbons
compounds that do not incorporate any unsaturated aromatic rings in their molecular structure
aliphatic compounds
a molecular shape that occurs when there are four bonds and no lone pairs in the molecule’s central atom
tetrahedral
weak, short-range electrostatic attractive forces between uncharged molecules, arising from the interaction of permanent or transient electric dipole moments
Van der Waals forces
