CD.a-n - Colour by design | CD1-11 |
CD.Q Exam questions from past papers
The aluminium (III) chloride reacts
vigorously with water
Explain why this reaction must be carried out in
anhydrous conditions?
● C as when the COOH group is
replaced with H it would be an
0.15 mol of fat required 10.8dm3 of hydrogen at alkene
room temperature and pressure for complete
hydrogenation
Identify which fatty acid formed the triester
Explain why compounds with an aromatic ring
usually form substituted derivatives, rather than
addition compounds? (1) ● Aromatic compounds have
delocalised electrons that are lost on
addition AND retained on
substitution (1)
● Less delocalisation causes less
stability (1)
CD.a-b - Bonding & Structure | CD5 | CD6 |
Define Colorfast dye? A dye that doesn’t wash out easily
What are the 4 different ways dyes attach ● Ionic bonds (between dyes and nylon,wool or
,themselves to fibres? silk)
● Covalent bonds (between dyes and cotton,
cellulose)
● Hydrogen bonds (between dyes and cotton)
● Id-id bonds (dyes and polyesters)
Mordanting as well in the textbook never seen it in past
paper though
What are the ways in which dyes bond to ● Ionic bonds via -COOH or -SO3H group on a
fibres and the functional groups to which dye and a -NH2 group in fibres (fibres such as
this occurs? wool, silk or nylon)
● Strong covalent bonds forming via fibre-
reactive dyes bonding with -OH or -NH group in
the fibre (cotton, cellulose)
● Hydrogen bonds via -NH2 groups on a dye and
a -OH group on a fibre (cellulose fibres such
as cotton, rayon or linen )
● Dissociation of ionic groups then forming
ionic bonds via dyes having -SO3-Na+ and
dissociating in water to produce -SO3- group and
then -NH2 group on the fibre (nylon,wool silk)
which in the presence of an acid produces -NH3+
which then -SO3- binds with -NH3+
● Acidic conditions (i.e in a weak acid) could
also mean -NH2 groups become protonated
and turn into -NH3+ on either dye or fibres
All of these are types of examples for which a dye could
bond to a fibre it does not represent all the ways so
make sure to interpret a question carefully bestie
Define Chromophore? A part of a molecule that is responsible for the colour of
a substance
It does this by changing the wavelength the electrons
absorb and they usually contain: double or triple bonds
like C=C or N=N, lone pair of electrons or benzene rings
Which atoms as part of the functional group ● Oxygen and Nitrogen atoms lone pair of
, on the chromophore/azo dye changes the electrons (mostly likely from an -OH or NH2
colour of the azo dye and why? group)
● As these groups have lone pair of electrons that
become part of the extended system of
delocalised electrons that spans between the
two benzene rings and the -N=N- group
● They change the frequency of light they absorb
and so the colour of the molecule
Which functional groups on the ● Usually ionic groups such as SO3- (usually in the
chromophore affect the solubility of the dye form of its sodium salt e.g -SO3-Na+)
AND what is the name of that functional ● As the SO3- group can form ion-dipoles with
group (1) water molecules which is stronger than
hydrogen bonds from an -OH or -NH2 group
● SO3- is a sulfonate group (1)
CD.c-f - Organic functional groups | CD2 | CD3 | CD4 | CD7 |
CD10 |
What are triglycerides? They are triesters of glycerol (propane-1,2,3-triol) and
(unsaturated or saturated) fatty acids
They usually ask about condensation or hydrolysis
reactions to do with these, make sure to balance the
equations correctly and a long chain group might be
CD.Q Exam questions from past papers
The aluminium (III) chloride reacts
vigorously with water
Explain why this reaction must be carried out in
anhydrous conditions?
● C as when the COOH group is
replaced with H it would be an
0.15 mol of fat required 10.8dm3 of hydrogen at alkene
room temperature and pressure for complete
hydrogenation
Identify which fatty acid formed the triester
Explain why compounds with an aromatic ring
usually form substituted derivatives, rather than
addition compounds? (1) ● Aromatic compounds have
delocalised electrons that are lost on
addition AND retained on
substitution (1)
● Less delocalisation causes less
stability (1)
CD.a-b - Bonding & Structure | CD5 | CD6 |
Define Colorfast dye? A dye that doesn’t wash out easily
What are the 4 different ways dyes attach ● Ionic bonds (between dyes and nylon,wool or
,themselves to fibres? silk)
● Covalent bonds (between dyes and cotton,
cellulose)
● Hydrogen bonds (between dyes and cotton)
● Id-id bonds (dyes and polyesters)
Mordanting as well in the textbook never seen it in past
paper though
What are the ways in which dyes bond to ● Ionic bonds via -COOH or -SO3H group on a
fibres and the functional groups to which dye and a -NH2 group in fibres (fibres such as
this occurs? wool, silk or nylon)
● Strong covalent bonds forming via fibre-
reactive dyes bonding with -OH or -NH group in
the fibre (cotton, cellulose)
● Hydrogen bonds via -NH2 groups on a dye and
a -OH group on a fibre (cellulose fibres such
as cotton, rayon or linen )
● Dissociation of ionic groups then forming
ionic bonds via dyes having -SO3-Na+ and
dissociating in water to produce -SO3- group and
then -NH2 group on the fibre (nylon,wool silk)
which in the presence of an acid produces -NH3+
which then -SO3- binds with -NH3+
● Acidic conditions (i.e in a weak acid) could
also mean -NH2 groups become protonated
and turn into -NH3+ on either dye or fibres
All of these are types of examples for which a dye could
bond to a fibre it does not represent all the ways so
make sure to interpret a question carefully bestie
Define Chromophore? A part of a molecule that is responsible for the colour of
a substance
It does this by changing the wavelength the electrons
absorb and they usually contain: double or triple bonds
like C=C or N=N, lone pair of electrons or benzene rings
Which atoms as part of the functional group ● Oxygen and Nitrogen atoms lone pair of
, on the chromophore/azo dye changes the electrons (mostly likely from an -OH or NH2
colour of the azo dye and why? group)
● As these groups have lone pair of electrons that
become part of the extended system of
delocalised electrons that spans between the
two benzene rings and the -N=N- group
● They change the frequency of light they absorb
and so the colour of the molecule
Which functional groups on the ● Usually ionic groups such as SO3- (usually in the
chromophore affect the solubility of the dye form of its sodium salt e.g -SO3-Na+)
AND what is the name of that functional ● As the SO3- group can form ion-dipoles with
group (1) water molecules which is stronger than
hydrogen bonds from an -OH or -NH2 group
● SO3- is a sulfonate group (1)
CD.c-f - Organic functional groups | CD2 | CD3 | CD4 | CD7 |
CD10 |
What are triglycerides? They are triesters of glycerol (propane-1,2,3-triol) and
(unsaturated or saturated) fatty acids
They usually ask about condensation or hydrolysis
reactions to do with these, make sure to balance the
equations correctly and a long chain group might be
