Predicting Physical
Properties of Molecules
from Functional Groups
Learning outcomes
• To become familiar with identifying key
functional groups within molecules.
• To be able to explain the influence of
functional groups on intermolecular forces.
• To be able to predict the physical properties of
molecules from functional groups present.
Butanoic acid has a powerful, unpleasant odour. It is
found in rancid butter, Parmesan cheese and vomit.
Carboxyl group
Can you identify and name the functional group
present in butanoic acid?
Aqueous solutions of methanal are commonly used in
embalming to preserve human or animal remains.
Carbonyl group
Can you identify and name the functional group present
in methanal?
Is methanal an aldehyde or a ketone?
Aldehyde
The molecule below is found in the disinfectant Dettol,
which we instantly recognise by its distinctive smell.
Dettol (chloroxylenol) helps us fight unwanted
bacteria.
Hydroxyl
group
Can you identify and name the functional group
present in Dettol?
4-formamidobenzoic acid is used in pharmaceutical
compositions.
Carboxyl
group
Amide group
Can you identify and name two functional groups
present on the 4-formamidobenzoic acid molecule?
Cinnamon is a tasty spice used to flavour biscuits,
cakes and pies. Cinnamon also has medicinal
properties.
Carbonyl
group
Carbon-tocarbon double
bond
Can you identify and name two functional groups in
cinnamon?
Is cinnamon an aldehyde or a ketone? Aldehyde
What is the strongest type of intermolecular force of
attraction between cinnamon molecules?
(Hint: Think about the bond polarity of the functional
groups present!)
Methyl anthranilate occurs naturally in grapes and
is used as grape flavouring in drinks and chewing
gum.
Ester link
Amino group
Can you identify and name the two functional
groups present in methyl anthranilate?
Vitamin C is needed in your diet for the growth and
repair of tissues in all parts of your body.
Ester link
Carbon-tocarbon double
bond
Hydroxyl
group
Can you identify and name three different types of
functional group on the structure of vitamin C?
Which is the strongest type of intermolecular force
of attraction between molecules of vitamin C?
Is vitamin C a polar or a non-polar molecule?
Is vitamin C soluble in water or in hexane?
(Hint: Think about which functional groups are present!)
Glucose is a simple sugar that is used as an energy
source by many living organisms.
Is glucose soluble in water or in hexane? Justify your
answer with reference to the functional groups present.
2-methylpropane is a branched hydrocarbon that is
used as a refrigerant.
Is 2-methylpropane soluble in water or in hexane?
Justify your answer with reference to the structure.