Esters, Fats And Oils Flashcards
(23 cards)
What functional group do esters contain?
An ester link -COO-
C=O
O
How are esters formed? (Type of reaction)
A condensation reaction
How are esters formed? (Molecules included)
By reacting an alcohol with a carboxylic acid forming and ester by eliminating water do the products are an ester and water
What’s a condensation reaction?
When two molecules are joined together with the elimination of a small molecule
What are the uses of esters?
They are often used as flavouring and fragrances as many have a pleasant, fruity smell.
Esters are also used as solvents for non-polar compounds, they can dissolve a variety of compounds and have low boiling points so can evaporate easily
What reaction breaks down an ester when reacting with water?
Hydrolysis reaction (ester hydrolysis)
What’s a hydrolysis reaction?
When a molecule reacts with water to break down into smaller molecules
What happens when an ester undergoes hydrolysis?
It reacts with water and breaks down to form an alcohol and a carboxylic acid forming
How are edible fats and oils formed?
They’re esters formed from the condensation reaction between three carboxylic acids and glycerol(three hydroxyl groups)
What is the chemical formula for glycerol?
Propane-1,2,3-triol
What are the carboxylic acids called that react with glycerol to form a fat/oil?
Fatty acids(normally 16-18 carbons)
Are fatty acid chains formed from no c=c double bonds saturated or unsaturated?
Saturated
Are fats formed from saturated or unsaturated fatty acids?
Saturated
Are fatty acid chains with one or more c=c double bonds saturated or unsaturated?
Unsaturated
Are oils formed from saturated or unsaturated fatty acids?
Unsaturated
Do edible oils or edible fats have a lower melting point?
Edible oils
Why do oils have a lower melting point compared to fats?
As they’re more unsaturated, because of the double bonds in fatty acids in oils the molecules have an uneven and distorted structure so they can’t pack closely together resulting in fewer attractions
(LDFs) between oil molecules therefore taking less energy to break them
Greater the unsaturation the lower the melting point
What forces of attraction are broken between fats and oils when melted?
London dispersion forces
How can you test the degree of unsaturation of an oil?
React the oil with bromine solution as they’ll decolourise bromine as they have double bonds and are unsaturated
What is the reaction between an oil and bromine solution called?
An addition reaction as bromine molecules add across the c=c double bonds saturated
What is the relationship between number of double bonds present and volume of bromine solution being decolourised?
The greater the number of C=C double bonds(greater the unsaturation) in a substance, the more bromine solution that will be decolourised
What are fats and oils a concentrated source of?
What are they essential for?
They’re a concentrated source of energy
They’re essential for the transport and storage of fat-soluble vitamins in the body like vitamin A/D
(Essential part of a healthy diet)
What is a catalyst for the hydrolysis reaction in esters?
Alkalis(sodium hydroxide)
