Pearson
REVISION GUIDE
Edexcel
IAL
CHEMISTRY
WCH16
, Homologous Series General formula Functional group
Alkane CnH2n+2
Alkene CnH2n
Alcohol CnH2n+1OH
–O–H
Halogenoalkane CnH2n+1X
(X is a halogen) –X
Aldehyde RCHO
Ketone RCOR’
Carboxylic acid CnH2n+1COOH
Nitrile RCN
Acyl chloride RCOCl
Ester RCOOR’
Amine RR’R’’N
Amide RCONHR’
Amino acid NH2CHRCOOH
Benzene:
,A-) Alkanes
The alkanes are a family of saturated hydrocarbons. They are saturated because they have
no double or triple bonds between the carbon atoms, so they contain the maximum amount
of hydrogen atoms possible. They are called hydrocarbons because they contain only carbon
and hydrogen atoms. All these hydrocarbons have certain properties in common:
➢ They are insoluble in water.
➢ They all burn, and in sufficient oxygen they give carbon dioxide and water as the only
combustion products.
The single most important source of alkanes is crude oil. Alkanes are obtained from
fractional distillation, cracking and reformation of crude oil.
• Reactions of alkanes
Reaction Reactants (conditions) Products
Cracking Long chain alkane (+ Alkenes + short-chain/
heat/zeolite catalyst) branched/ cyclic alkanes
Reforming Straight chain alkane (+ Branched alkanes/arenes
platinum catalyst + heat) (e.g. benzene) + H2
Combustion:
Complete combustion Sufficient oxygen (+ heat) CO2 + H2O
Incomplete combustion Insufficient oxygen (+heat) C + CO + H2O
Free radical substitution with chlorine Alkane + Cl2 + (UV light) Halogenoalkane + alkane
Although alkanes combust well, they are unreactive. The reason for this lack of reactivity is
that both C-C and C-H bonds involve a very even sharing of electrons, since the
electronegativities of carbon and hydrogen are very close. This means that the bonds in the
molecules of the alkanes are not polar to any extent, and there are no charges to attract
other polar or ionic species. Almost all the reactions of the alkanes occur due to formation of
free radicals which contain an unpaired electron.
2
, 3
REVISION GUIDE
Edexcel
IAL
CHEMISTRY
WCH16
, Homologous Series General formula Functional group
Alkane CnH2n+2
Alkene CnH2n
Alcohol CnH2n+1OH
–O–H
Halogenoalkane CnH2n+1X
(X is a halogen) –X
Aldehyde RCHO
Ketone RCOR’
Carboxylic acid CnH2n+1COOH
Nitrile RCN
Acyl chloride RCOCl
Ester RCOOR’
Amine RR’R’’N
Amide RCONHR’
Amino acid NH2CHRCOOH
Benzene:
,A-) Alkanes
The alkanes are a family of saturated hydrocarbons. They are saturated because they have
no double or triple bonds between the carbon atoms, so they contain the maximum amount
of hydrogen atoms possible. They are called hydrocarbons because they contain only carbon
and hydrogen atoms. All these hydrocarbons have certain properties in common:
➢ They are insoluble in water.
➢ They all burn, and in sufficient oxygen they give carbon dioxide and water as the only
combustion products.
The single most important source of alkanes is crude oil. Alkanes are obtained from
fractional distillation, cracking and reformation of crude oil.
• Reactions of alkanes
Reaction Reactants (conditions) Products
Cracking Long chain alkane (+ Alkenes + short-chain/
heat/zeolite catalyst) branched/ cyclic alkanes
Reforming Straight chain alkane (+ Branched alkanes/arenes
platinum catalyst + heat) (e.g. benzene) + H2
Combustion:
Complete combustion Sufficient oxygen (+ heat) CO2 + H2O
Incomplete combustion Insufficient oxygen (+heat) C + CO + H2O
Free radical substitution with chlorine Alkane + Cl2 + (UV light) Halogenoalkane + alkane
Although alkanes combust well, they are unreactive. The reason for this lack of reactivity is
that both C-C and C-H bonds involve a very even sharing of electrons, since the
electronegativities of carbon and hydrogen are very close. This means that the bonds in the
molecules of the alkanes are not polar to any extent, and there are no charges to attract
other polar or ionic species. Almost all the reactions of the alkanes occur due to formation of
free radicals which contain an unpaired electron.
2
, 3
