Topic 10.1: Organic chemistry – Fundamentals of organic chemistry
Organic chemistry focuses on the chemistry of compounds containing carbon.
• Understanding: A homologous series is a series of compounds of the same family, with the same general formula, which differ from
each other by a common structural unit.
▪ Homologous series: series of compound of the same family, with the same general formula, which differ by a common structural unit
• Common structure unit: often CH2 (methylene) group
• Same family: has the same functional group
• Properties: homologous series has similar physical and chemical properties
• Understanding: Structural formulas can be represented in full and condensed format.
Full structural formula Condensed structural formula Skeletal structural formula
Example
Description Two dimensional representation Two dimensional representation Two dimensional representation of a
showing all atoms, their relative showing all atoms and their relative compound where each vertex and
positions and bonds position end of line represent a carbon atom,
and functional group is added
• Understanding: Structural isomers are compounds with the same molecular formula but different arrangements of atoms.
▪ Structure isomer: compounds with same molecular formula with different arrangement of atoms
• Properties: structure isomers have different chemical and physical properties (melting point, boiling point etc.)
• Understanding: Functional groups are the reactive parts of molecules.
▪ Functional groups: reactive parts of a molecule that is responsible for the molecule’s chemical property
• Naming: the position of the function group is identified by the number of carbon to which it is attached
• Understanding: Saturated compounds contain single bonds only and unsaturated compounds contain double or triple bonds.
▪ Saturated compounds: organic compounds in which all the carbon-carbon bonds are single (e.g. alkane)
▪ Unsaturated compounds: organic compound in which there is at least one carbon-carbon bond that is double or triple (e.g. alkene)
• Understanding: Benzene is an aromatic, unsaturated hydrocarbon.
▪ Aliphatic: characterized by a straight, branched or cyclic structure
▪ Aromatic: characterized by presence of benzene ring
▪ Benzene: aromatic, unsaturated hydrocarbon in which six carbons bonds into a ring
• Sigma (σ) bond in benzene: benzene contains six sp2 hybridized carbon atoms bond to one other by sigma bonds
• Pi (π) bond in benzene: p-orbitals in carbon overlap to form a continuous π bond above and below the plane of carbons
• Applications and skills: Explanation of the trends in boiling points of members of a homologous series.
Name Formula Structural formula (condensed) Boiling point (°C)
Methane CH4 CH4 -161
Ethane C2H6 CH3CH3 -89
Propane C3H8 CH3CH2CH3 -42
Butane C4H10 CH3CH2CH2CH3 -0.5
Pentane C5H12 CH3CH2CH2CH2CH3 36
Hexane C6H14 CH3CH2CH2CH2CH2CH3 69
▪ Trend in boiling points: boiling points increases as the carbon chain increases by a common structural unit
• Trends arise from increasing intermolecular (dispersion forces) with increased chain lengths
• Applications and skills: Distinction between empirical, molecular and structural formulas.
▪ Empirical formula: simplest ratio of atoms (of an element) in a molecule
▪ Molecular formula: actual number of atoms (of each element) in a molecule
▪ Structural formula: representation of the type of atom and their position relative to one other
, • Applications and skills: Identification of different classes: alkanes, alkenes, alkynes, halogenoalkanes, alcohols, ethers, aldehydes,
ketones, esters, carboxylic acids, amines, amides, nitriles and arenes.
• Applications and skills: Identification of typical functional groups in molecules eg phenyl, hydroxyl, carbonyl, carboxyl, carboxamide,
aldehyde, ester, ether, amine, nitrile, alkyl, alkenyl and alkynyl.
Class Functional group Diagram General formula Prefix Suffix Example
Alkane Alkyl CnH2n+2 Alkyl- -ane Propane
Alkene Alkenyl CnH2n Alkenyl- -ene But-2-ene
Alkyne Alkynyl CnH2n-2 Alkynyl- -ne But-2-yne
Halogenoalkane -X (x= F, Cl, Br, I) CnH2n+1X Halo- 2-chlorobutane
Alcohol Hydroxyl ROH Hydroxy- -ol Butan-2-ol
Ether Ether ROR’ Alkoxy- -ane Methoxyethane
Aldehyde Aldehyde RCHO Formyl- -al Ethanal
Ketone Carbonyl RC(O)R’ Oxo- -one Propanone
2-pentanone
Ester Ester RCOOR’ -Alkyl -oate Methyl propanoate
(from (from acid)
alcohol)
Carboxylic acid Carboxyl RCOOH -oic acid Ethanoic acid
Amine Amine RNH2 Amino- -amine Propan-1-amine
RNHR’ N-methyl ethamine
RN(R’)R’’ N,N-dimethyl ethanamine
Amide Amide RCONH2 -amine Ethanamide
Nitrile Nitrile RCN Cyno- -nitrile Propanenitrile
Arene Phenyl C6H6 Phenyl- Benzene
• Applications and skills: Application of IUPAC rules in the nomenclature of straight-chain and branched- chain isomers.
▪ IUPAC rules in naming organic compounds
• Principal (parent) chain: longest carbon chain; provides the root name for the alkane
• Branched chain: alkyl substituents can be branched from the parent chain
• Position of branched chain: must be the lowest numbered carbon (e.g. 2-methylbutane, not 3-methylbutane)
• Order of branched chain: must come in alphabetical order (e.g. ethyl comes before methyl, then propyl)
• Use commas (,) to separate numbers, hyphens (-) to separate number and letters (e.g. 2, 2-dimethylpropane)
Class Naming system Example
Alcohol Identical as alkane naming but with name ending with an –ol instead of – Hydroxyl group attached to carbon 2 in
ane; number before suffix indicates position butane: butan-2-ol
Aldehydes Identical as alkane naming but with name ending with an –al instead of – Aldehyde group attached to terminal carbon
ane; aldehyde is always in terminal position so is not required to number in butane: butanal (not required to number)
Halogenoalkanes Identical as alkane naming with a prefix of the respective halogen; number Fluorine attached to carbon 2 in butane: 2-
before prefix indicates position flourobutane
Esters Alcohol side (one attached to oxygen) of ester becomes the alkyl prefix, Methyl propanoate; methyl from methanol
carboxylic (one opposite of oxygen) side of ester becomes the –oate suffix and propanoate from propanoic acid
Ethers Alkane chain (shorter) as a prefix, followed by an –oxy, finishing through Methane group and ethane group attached
the other alkane chain (longer) opposite of a ether: methoxy ethane
Ketones Identical as alkane naming with naming ending with an -one; number Ketone group attached to carbon 2 in
before prefix indicates position pentane: 2-pentanone
Carboxylic acids Identical as alkane naming but with name ending with an –oxylic acid Ethane parent alkane chain with hydroxyl
instead of –ane; hydroxyl is always in terminal position so is not required to terminal: ethanoic acid
number
Organic chemistry focuses on the chemistry of compounds containing carbon.
• Understanding: A homologous series is a series of compounds of the same family, with the same general formula, which differ from
each other by a common structural unit.
▪ Homologous series: series of compound of the same family, with the same general formula, which differ by a common structural unit
• Common structure unit: often CH2 (methylene) group
• Same family: has the same functional group
• Properties: homologous series has similar physical and chemical properties
• Understanding: Structural formulas can be represented in full and condensed format.
Full structural formula Condensed structural formula Skeletal structural formula
Example
Description Two dimensional representation Two dimensional representation Two dimensional representation of a
showing all atoms, their relative showing all atoms and their relative compound where each vertex and
positions and bonds position end of line represent a carbon atom,
and functional group is added
• Understanding: Structural isomers are compounds with the same molecular formula but different arrangements of atoms.
▪ Structure isomer: compounds with same molecular formula with different arrangement of atoms
• Properties: structure isomers have different chemical and physical properties (melting point, boiling point etc.)
• Understanding: Functional groups are the reactive parts of molecules.
▪ Functional groups: reactive parts of a molecule that is responsible for the molecule’s chemical property
• Naming: the position of the function group is identified by the number of carbon to which it is attached
• Understanding: Saturated compounds contain single bonds only and unsaturated compounds contain double or triple bonds.
▪ Saturated compounds: organic compounds in which all the carbon-carbon bonds are single (e.g. alkane)
▪ Unsaturated compounds: organic compound in which there is at least one carbon-carbon bond that is double or triple (e.g. alkene)
• Understanding: Benzene is an aromatic, unsaturated hydrocarbon.
▪ Aliphatic: characterized by a straight, branched or cyclic structure
▪ Aromatic: characterized by presence of benzene ring
▪ Benzene: aromatic, unsaturated hydrocarbon in which six carbons bonds into a ring
• Sigma (σ) bond in benzene: benzene contains six sp2 hybridized carbon atoms bond to one other by sigma bonds
• Pi (π) bond in benzene: p-orbitals in carbon overlap to form a continuous π bond above and below the plane of carbons
• Applications and skills: Explanation of the trends in boiling points of members of a homologous series.
Name Formula Structural formula (condensed) Boiling point (°C)
Methane CH4 CH4 -161
Ethane C2H6 CH3CH3 -89
Propane C3H8 CH3CH2CH3 -42
Butane C4H10 CH3CH2CH2CH3 -0.5
Pentane C5H12 CH3CH2CH2CH2CH3 36
Hexane C6H14 CH3CH2CH2CH2CH2CH3 69
▪ Trend in boiling points: boiling points increases as the carbon chain increases by a common structural unit
• Trends arise from increasing intermolecular (dispersion forces) with increased chain lengths
• Applications and skills: Distinction between empirical, molecular and structural formulas.
▪ Empirical formula: simplest ratio of atoms (of an element) in a molecule
▪ Molecular formula: actual number of atoms (of each element) in a molecule
▪ Structural formula: representation of the type of atom and their position relative to one other
, • Applications and skills: Identification of different classes: alkanes, alkenes, alkynes, halogenoalkanes, alcohols, ethers, aldehydes,
ketones, esters, carboxylic acids, amines, amides, nitriles and arenes.
• Applications and skills: Identification of typical functional groups in molecules eg phenyl, hydroxyl, carbonyl, carboxyl, carboxamide,
aldehyde, ester, ether, amine, nitrile, alkyl, alkenyl and alkynyl.
Class Functional group Diagram General formula Prefix Suffix Example
Alkane Alkyl CnH2n+2 Alkyl- -ane Propane
Alkene Alkenyl CnH2n Alkenyl- -ene But-2-ene
Alkyne Alkynyl CnH2n-2 Alkynyl- -ne But-2-yne
Halogenoalkane -X (x= F, Cl, Br, I) CnH2n+1X Halo- 2-chlorobutane
Alcohol Hydroxyl ROH Hydroxy- -ol Butan-2-ol
Ether Ether ROR’ Alkoxy- -ane Methoxyethane
Aldehyde Aldehyde RCHO Formyl- -al Ethanal
Ketone Carbonyl RC(O)R’ Oxo- -one Propanone
2-pentanone
Ester Ester RCOOR’ -Alkyl -oate Methyl propanoate
(from (from acid)
alcohol)
Carboxylic acid Carboxyl RCOOH -oic acid Ethanoic acid
Amine Amine RNH2 Amino- -amine Propan-1-amine
RNHR’ N-methyl ethamine
RN(R’)R’’ N,N-dimethyl ethanamine
Amide Amide RCONH2 -amine Ethanamide
Nitrile Nitrile RCN Cyno- -nitrile Propanenitrile
Arene Phenyl C6H6 Phenyl- Benzene
• Applications and skills: Application of IUPAC rules in the nomenclature of straight-chain and branched- chain isomers.
▪ IUPAC rules in naming organic compounds
• Principal (parent) chain: longest carbon chain; provides the root name for the alkane
• Branched chain: alkyl substituents can be branched from the parent chain
• Position of branched chain: must be the lowest numbered carbon (e.g. 2-methylbutane, not 3-methylbutane)
• Order of branched chain: must come in alphabetical order (e.g. ethyl comes before methyl, then propyl)
• Use commas (,) to separate numbers, hyphens (-) to separate number and letters (e.g. 2, 2-dimethylpropane)
Class Naming system Example
Alcohol Identical as alkane naming but with name ending with an –ol instead of – Hydroxyl group attached to carbon 2 in
ane; number before suffix indicates position butane: butan-2-ol
Aldehydes Identical as alkane naming but with name ending with an –al instead of – Aldehyde group attached to terminal carbon
ane; aldehyde is always in terminal position so is not required to number in butane: butanal (not required to number)
Halogenoalkanes Identical as alkane naming with a prefix of the respective halogen; number Fluorine attached to carbon 2 in butane: 2-
before prefix indicates position flourobutane
Esters Alcohol side (one attached to oxygen) of ester becomes the alkyl prefix, Methyl propanoate; methyl from methanol
carboxylic (one opposite of oxygen) side of ester becomes the –oate suffix and propanoate from propanoic acid
Ethers Alkane chain (shorter) as a prefix, followed by an –oxy, finishing through Methane group and ethane group attached
the other alkane chain (longer) opposite of a ether: methoxy ethane
Ketones Identical as alkane naming with naming ending with an -one; number Ketone group attached to carbon 2 in
before prefix indicates position pentane: 2-pentanone
Carboxylic acids Identical as alkane naming but with name ending with an –oxylic acid Ethane parent alkane chain with hydroxyl
instead of –ane; hydroxyl is always in terminal position so is not required to terminal: ethanoic acid
number
