Fats and Oils Flashcards
What do fats and oils do?
They are used in our diets to provide us with energy. They play an important role in the transport of vitamins which are soluble in fats around the human body. More concentrated form than carbs.
What are fats and oils and how are they made?
All fats and oils are naturally occurring esters so are formed by a condensation/esterification reaction between glycerol and long chain fatty acids.
What are the properties of glycerol?
Called propane-1,2,3-triol
Has three hydroxyl functional groups
More viscous than other alcohols
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So, what is the reaction for a fat or an oil?
Glycerol + Fatty Acid —> Ester (fat/oil) + Water
What does the result of a fat or oil depend on?
It depends on the fatty acid that the ester is formed from.
Fats are from mainly saturated fatty acids.
Oil are from highly unsaturated fatty acids
The properties of fats…
They have an even structure which allows for close packing of the molecules.
The closer together the molecules the greater the number of LDFs between the fat molecules.
The more LDFs the harder it is to break the molecules apart
Therefore fats have high mp and by
Hence fats are solid and saturated
Properties of oils…
Uneven, distorted structure so harder to pack the molecules closely together
=less LDFs between oil molecules meaning its easier to break the molecules apart
Therefore oils have lower mp and by than fats
Hence oils are liquid and unsaturated
How to convert oils to fats?
By hydrogenation - an addition reaction where hydrogen is added across the double bond
What happens during hydrogenation of oils?
The double bonds become single (saturated)
Increasing the level of saturation in oil increases how closely the molecules pack
Increases LDFs and increases mp and bp
How do you turn a fat or oil back into the original fatty acid and glycerol?
A hydrolysis reaction
Exam Q - Coconut Oil has a melting point of 25°C. Whilst Olive Oil has a melting point of -6°C. Give two reasons why coconut oil has a higher melting point than olive oil.
Coconut oil molecules can pack more closely together
There are more/stronger intermolecular forces between the molecules in coconut oil
