IEB Organic Chemistry Notes
Organic chemistry = branch of chemistry that studies carbon compounds
• Organic molecules = molecules containing carbon EXCEPT FOR:
1. Carbon dioxide 2. Diamond
3. Carbon monoxide 4. Graphite
5. Carbonates 6. Bicarbonates
7. Carbides 8. Cyanides
• `Carbon = basic building block of organic compounds that recycle through the Earth’s air, water, soil and
living organisms
PROPERTIES OF ORGANIC COMPOUNDS
Low melting points
Usually non polar (unless have functional groups which give polarity)
Non conductors of electricity
Exist in solid, liquid and gaseous form
• 1-4 carbons = gases at room temp
• 5-10 carbons = liquid at room temp
• 12-18 carbons = jet fuels and kerosene
• More than 18 carbons = solids at room temp
Can exist as polymers
• Many repeating units (monomers) make up a larger molecule
• Eg. Amino acids = protein monomers
• Eg. Plastics = polymers of organic molecules extracted from crude oil
SOURCES OF CARBON AND CARBON COMPOUNDS
• Carbon dioxide — converted to organic compounds via photosynthesis
• Fossil fuels
• Coal
• Petroleum
• Natural gas
• Diamond and graphite
CARBON’S UNIQUE BONDING ABILITY
• Carbon has a valency of 4 in a tetrahedral arrangement
• Result of hybridisation
• Bonds formed are predominantly covalent in character — explains non-polar x
nature of organic compounds
• Covalent bonds formed with itself and other elements = strong covalent bonds
xCx
• C—H bond = ALMOST purely covalent because of very small electronegativity .x.
di erence
• C—C bond = purely covalent
• Valence electrons not bonded to C—C = available for bonding with H,N,O,S
and other elements
• Carbon can make single, double and triple bonds
• Carbon can bond with other elements to form chains, ring, spheres and tubes
CATENATION = ability of carbon to form long chains by bonding with other carbon atoms
1
ff
, FRACTIONAL DISTILLATION OF CRUDE OIL/NATURAL GAS
• Crude oil/petroleum = mixture of several compounds of carbon
found deep within the Earth’s crust
• Petra = rock vs oleum = oil
• Petroleum formed because of decomposition of microorganisms
buried under the sea
• Takes place in the absence of air or oxygen
Petroleum has many impurities…+ mixture of many hydrocarbon
compounds
Re ning of petroleum = process by whereby petroleum is
separated into its components along with the separation of
impurities
• Done through fractional distillation
“The crude oil obtained from the oil wells is heated to 400°C. The
volatile components from the oil start evaporating and they are made to pass through a fractionalizing
column. As the mixtures of vapours rise, they cool. As they cool, di erent components condense and are
then separated out by collecting funnels. The gradual cooling of the vapours along the tower height means
that vapours with higher boiling points condense rst. The vapours having lower boiling points are
collected at higher levels in the tower. Gases do not liquefy at such high temperatures and are removed at
the top of the tower. Petroleum is distilled into many fractions, and there may be ve to six fractions. The
residue from the petroleum is removed from the bottom of the furnace and is subjected to further
fractional distillation by raising the temperature above 400°C in another fractional distillation tower.”
CLASSIFICATION
• Classi ed based on the type of bonds
SATURATED COMPOUND = compound in which all the bonds between carbon atoms are single bonds
UNSATURATED COMPOUND = a compound in which there is at least one double and/or triple bond
between carbon atoms
• Classi ed based on the type of structure
HYDROCARBON = a compound containing only carbon and hydrogen atoms
FUNCTIONAL GROUP = an atom or group of atoms that form the centre of chemical activity in the
molecule
HOMOLOGOUS SERIES = series of similar compounds which have the same functional group and have
the same general formula in which each member di ers from the previous one by one sing CH2 unit
2
fi fi ff fi ff fi
, • Di erentiating hydrocarbons
• Aliphatic vs aromatic
• Aliphatic = open chain structures (acyclic) or ring structures (cyclic)
• Aromatic = have a characteristic small or aroma (unsaturated ring structures eg.
Benzene)
Benzene Ring
DIFFERENT WAYS OF REPRESENTING ORGANIC COMPOUNDS
3
ff
Organic chemistry = branch of chemistry that studies carbon compounds
• Organic molecules = molecules containing carbon EXCEPT FOR:
1. Carbon dioxide 2. Diamond
3. Carbon monoxide 4. Graphite
5. Carbonates 6. Bicarbonates
7. Carbides 8. Cyanides
• `Carbon = basic building block of organic compounds that recycle through the Earth’s air, water, soil and
living organisms
PROPERTIES OF ORGANIC COMPOUNDS
Low melting points
Usually non polar (unless have functional groups which give polarity)
Non conductors of electricity
Exist in solid, liquid and gaseous form
• 1-4 carbons = gases at room temp
• 5-10 carbons = liquid at room temp
• 12-18 carbons = jet fuels and kerosene
• More than 18 carbons = solids at room temp
Can exist as polymers
• Many repeating units (monomers) make up a larger molecule
• Eg. Amino acids = protein monomers
• Eg. Plastics = polymers of organic molecules extracted from crude oil
SOURCES OF CARBON AND CARBON COMPOUNDS
• Carbon dioxide — converted to organic compounds via photosynthesis
• Fossil fuels
• Coal
• Petroleum
• Natural gas
• Diamond and graphite
CARBON’S UNIQUE BONDING ABILITY
• Carbon has a valency of 4 in a tetrahedral arrangement
• Result of hybridisation
• Bonds formed are predominantly covalent in character — explains non-polar x
nature of organic compounds
• Covalent bonds formed with itself and other elements = strong covalent bonds
xCx
• C—H bond = ALMOST purely covalent because of very small electronegativity .x.
di erence
• C—C bond = purely covalent
• Valence electrons not bonded to C—C = available for bonding with H,N,O,S
and other elements
• Carbon can make single, double and triple bonds
• Carbon can bond with other elements to form chains, ring, spheres and tubes
CATENATION = ability of carbon to form long chains by bonding with other carbon atoms
1
ff
, FRACTIONAL DISTILLATION OF CRUDE OIL/NATURAL GAS
• Crude oil/petroleum = mixture of several compounds of carbon
found deep within the Earth’s crust
• Petra = rock vs oleum = oil
• Petroleum formed because of decomposition of microorganisms
buried under the sea
• Takes place in the absence of air or oxygen
Petroleum has many impurities…+ mixture of many hydrocarbon
compounds
Re ning of petroleum = process by whereby petroleum is
separated into its components along with the separation of
impurities
• Done through fractional distillation
“The crude oil obtained from the oil wells is heated to 400°C. The
volatile components from the oil start evaporating and they are made to pass through a fractionalizing
column. As the mixtures of vapours rise, they cool. As they cool, di erent components condense and are
then separated out by collecting funnels. The gradual cooling of the vapours along the tower height means
that vapours with higher boiling points condense rst. The vapours having lower boiling points are
collected at higher levels in the tower. Gases do not liquefy at such high temperatures and are removed at
the top of the tower. Petroleum is distilled into many fractions, and there may be ve to six fractions. The
residue from the petroleum is removed from the bottom of the furnace and is subjected to further
fractional distillation by raising the temperature above 400°C in another fractional distillation tower.”
CLASSIFICATION
• Classi ed based on the type of bonds
SATURATED COMPOUND = compound in which all the bonds between carbon atoms are single bonds
UNSATURATED COMPOUND = a compound in which there is at least one double and/or triple bond
between carbon atoms
• Classi ed based on the type of structure
HYDROCARBON = a compound containing only carbon and hydrogen atoms
FUNCTIONAL GROUP = an atom or group of atoms that form the centre of chemical activity in the
molecule
HOMOLOGOUS SERIES = series of similar compounds which have the same functional group and have
the same general formula in which each member di ers from the previous one by one sing CH2 unit
2
fi fi ff fi ff fi
, • Di erentiating hydrocarbons
• Aliphatic vs aromatic
• Aliphatic = open chain structures (acyclic) or ring structures (cyclic)
• Aromatic = have a characteristic small or aroma (unsaturated ring structures eg.
Benzene)
Benzene Ring
DIFFERENT WAYS OF REPRESENTING ORGANIC COMPOUNDS
3
ff
