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Electronegativity is the ability to attract the bonding electrons in a covalent bond
Atoms with strong electron pulling power in covalent bonds are said to be highly electronegative.
Fluorine is the most electronegative element.
Oxygen, nitrogen chlorine are also strongly electronegative.
In a covalent bond between two atoms of
different electronegativities, the bonding
electrons are pulled towards the more
electronegative atom.
This makes the bond polar.
The covalent bonds in diatomic elements are
non-polar because the atoms have equal
electronegativities.…read more

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Whether a molecule has a permanent dipole depends on its shape and the polarity of its bonds.
1. In a simple molecule, like hydrogen bromide, the polar bond gives the whole molecule a permanent
dipole ­ it's a polar molecule.
2. A more complicated molecule may have several polar bonds.
If the polar bonds are arranged so they point in opposite directions, they'll cancel each other out.
The molecule is non-polar overall.
3.…read more

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Intermolecular forces are forces between molecules.
They are much weaker than covalent, ionic or metallic bonds.
Permanent Dipole ­ Permanent Dipole
Permanent dipoles occur when a molecule has two atoms bonded
together which have substantially different electronegativities so
that one atom attracts the shared electrons much more than the
Molecules with a permanent dipole are polar molecules.
One side of the molecule is positive, one is negative.…read more

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Oils and fats are naturally occurring triesters of propane-1,2,3-triol and long-chain carboxylic acids.
Each of the three ester groups can be from the same fatty acid or they can be different.
Glycerol Triester
Fatty Acids
Fatty acids are the carboxylic acids in fats and oils.
They have an even number of carbons in their unbranched
carbon chain.
These chains can either be saturated or unsaturated.
Any natural oil or fat contains a mixture of triesters.
Triesters from largely saturated fatty acids are solids or fats.…read more

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The simplest arene is benzene.
It's chemical formula is C6H6.
It has a flat hexagonal structure with a bond angle of 120O.
Arenes are hydrocarbons that contain benzene rings.
Their names always end in ­ene, meaning that they are unsaturated.
All carbon-carbon bond lengths are the same, with a value between that of a single and double bond.
They are shorter than a carbon-carbon single bond but longer than a carbon=carbon double bond.…read more

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The delocalised electrons in a benzene ring are spread out in a cloud which
extends above and below the plane of the benzene ring. Electrophiles
These regions of higher electron density tend to attract more positive are positive
ions, or atoms with a partial positive charge within molecules ­ so ions with a
partial positive
benzene, like alkenes, reacts with electrophiles.
localised on
Unlike alkenes, arenes usually undergo substitution reactions, but vary one of the
rarely addition reactions.…read more

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Nitration Reaction Sulfonation Reaction
Chlorination Reaction Bromination Reaction
Acylation Reaction
Alkylation Reaction…read more

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Aromatic amines are used to make azo dyes.
Azo dyes contain the azo group ­N=N-.
In azo dyes, the azo group links the two aromatic groups.
Having two aromatic groups creates a very stable molecule.
The azo group becomes part of the delocalised electron system.
The colours are the result of light absorption by the delocalised electron system.
Different colours are made by combining different phenols and amines.
Making Azo Dyes
Azo dyes are made by reacting a coupling agent with a diazonium ion.…read more


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