2b. Esters, Fats, Oils, Soaps, detergents and Emulsifiers Flashcards
What is the functional group in esters?
The ester link
Which 2 homologous series react together to form esters?
Alcohols and carboxylic acids
What are the properties of a common ester (pentyl ethanoate)?
What are the 3 main uses for esters?
What type of reaction is undergone when an ester is formed?
A condensation reaction
What are sources of fats and oils
What category of compounds are fats and oils?
They are esters
Why are fats and oils sometimes called tri-esters?
Because they have 3 carboxylate (ester link) groups in each molecule
What is the parent alkanol in all fats and oils?
Glycerol
(Propan-1, 2, 3 triol)
What is the structure of glycerol?
What is meant by a fatty acid?
A long chain carboxylic acid with a 16 or 18 carbon chain
What is the ratio of fatty acid to glycerol molecules when a fat or oil is made?
3:1
What are the differences between fats and oils?
What is meant by an “unsaturated” molecule?
A molecule with at least 1 C=C bond present
Testing fats and oils for levels of unsaturation
Also see video on google classroom
What effect does unsaturation have on the shape of tri-esters?
What effect does the irregular shape of unsaturated “tuning fork” have on how the molecules pack together?
How could the levels of unsaturation in oils / fats be tested?
Bromine (or Iodine) will add across the C=C bond and decolourise as it does so.
A clear end point will be shown when the decolourising stops.
The more C=C bonds there are, the higher the volume of Br2 or I2 it will take to reach end point
Tri-esters are also known as what (based on glycerol name)
Tri-glycerides
Why are some oils hydrogenated?
To make them have higher melting points and be more stable.
What are the 6 points needed to be covered to explain difference in melting points of fats and oils?
- Level of unsaturation (C=C bonds)
- Effect this has on tuning fork shape
- Effect this has on how close they can pack together
- Effect this has on intermoleular (LDF) attractions
- Level of energy need to break them
- corresponding lower or higher melting point
What happens to fats and oils when they react with oxygen?
They become rancid
What is meant by “hydrolysis”?
The breaking down of a molecule using the chemical action of water
Which molecule is ALWAYS produced when fats and oils are hydrolysed?
Glycerol



