Name: Orlando Nica
Student ID: 20413435
Qualification: Pearson BTEC Level 3 National Extended Diploma in
Applied Science
Unit number and title: Unit 14: Applications of Organic Chemistry
Learning aim B: Understand the reactions and properties of aromatic
compounds.
Aromatic ring chemistry for designer chemicals
Introduction: The aim of this assignment is to explain the chemical properties
of an aromatic compound often used in the chemical industry called benzene.
Together with a handbook, the structure of benzene will be explained in terms
of sigma and pi bonding providing the evidence to its structure.
The effects of different mono substituents on the benzene ring will be analysed
in order to predict further substitution position(s) of a reaction species on the
benzene ring.
Benzene (C6H6)
Benzene is a chemical that is a colourless or light yellow liquid at room
temperature. It has a sweet odour and is highly flammable. It evaporates into the
air very quickly, its vapour is heavier than air and may sink into low-lying areas.
Benzene dissolves only slightly in water and will float on top of water.
1
, Benzene, C6H6, is a planar molecule containing a ring of six carbon atoms each
with a hydrogen atom attached. The six carbon atoms form a perfectly regular
hexagon, it is a regular hexagon because all the bonds are identical. All the
carbon-carbon bonds have exactly the same lengths - somewhere between single
and double bonds.
As displayed in the diagram above one of the molecular orbitals contains two of
the delocalised electrons, which may be found anywhere within the two
"doughnuts". These two delocalised electrons make benzene stable.
Benzene is built from hydrogen atoms (1s1) and carbon atoms (1s22s22px12py1).
Each carbon atom has to join to three other atoms (one hydrogen and two
carbons) and doesn't have enough unpaired electrons to form the required
number of bonds, so it needs to promote one of the 2s2 pair into the empty 2pz
orbital.
There is only a small energy gap between the 2s and 2p orbitals, and an electron
is promoted from the 2s to the empty 2p to give 4 unpaired electrons. The extra
energy released when these electrons are used for bonding more than
compensates for the initial input.
This is how the carbon atom gets in the excited state.
Hybridisation- Because each carbon is only joining to three other atoms, when
the carbon atoms hybridise their outer orbitals before forming bonds, they only
need to hybridise three of the orbitals rather than all four. They use the 2s
electron and two of the 2p electrons, but leave the other 2p electron unchanged.
2
Student ID: 20413435
Qualification: Pearson BTEC Level 3 National Extended Diploma in
Applied Science
Unit number and title: Unit 14: Applications of Organic Chemistry
Learning aim B: Understand the reactions and properties of aromatic
compounds.
Aromatic ring chemistry for designer chemicals
Introduction: The aim of this assignment is to explain the chemical properties
of an aromatic compound often used in the chemical industry called benzene.
Together with a handbook, the structure of benzene will be explained in terms
of sigma and pi bonding providing the evidence to its structure.
The effects of different mono substituents on the benzene ring will be analysed
in order to predict further substitution position(s) of a reaction species on the
benzene ring.
Benzene (C6H6)
Benzene is a chemical that is a colourless or light yellow liquid at room
temperature. It has a sweet odour and is highly flammable. It evaporates into the
air very quickly, its vapour is heavier than air and may sink into low-lying areas.
Benzene dissolves only slightly in water and will float on top of water.
1
, Benzene, C6H6, is a planar molecule containing a ring of six carbon atoms each
with a hydrogen atom attached. The six carbon atoms form a perfectly regular
hexagon, it is a regular hexagon because all the bonds are identical. All the
carbon-carbon bonds have exactly the same lengths - somewhere between single
and double bonds.
As displayed in the diagram above one of the molecular orbitals contains two of
the delocalised electrons, which may be found anywhere within the two
"doughnuts". These two delocalised electrons make benzene stable.
Benzene is built from hydrogen atoms (1s1) and carbon atoms (1s22s22px12py1).
Each carbon atom has to join to three other atoms (one hydrogen and two
carbons) and doesn't have enough unpaired electrons to form the required
number of bonds, so it needs to promote one of the 2s2 pair into the empty 2pz
orbital.
There is only a small energy gap between the 2s and 2p orbitals, and an electron
is promoted from the 2s to the empty 2p to give 4 unpaired electrons. The extra
energy released when these electrons are used for bonding more than
compensates for the initial input.
This is how the carbon atom gets in the excited state.
Hybridisation- Because each carbon is only joining to three other atoms, when
the carbon atoms hybridise their outer orbitals before forming bonds, they only
need to hybridise three of the orbitals rather than all four. They use the 2s
electron and two of the 2p electrons, but leave the other 2p electron unchanged.
2
