Unit 2 : Esters, Fats and Oils Flashcards
Write a word equation for the formation of Esters.
Alcohol + Carboxylic Acid —> Ester + Water
What is Esters used in?
Flavourings: Esters are responsible for the smell and flavour of many fruits and flowers. They are used as artificial flavourings.
Fragrances: They are used in perfumes as fragrance which includes apple, bananas, etc.
Non-Polar industrial Solvents : Ethyl Ethanoate can be used to extract caffeine from coffee and tea. Esters are used as solvents for dyes, drugs, antibiotics, glues, paints and varnishes.
How are Esters formed?
Esters are formed by the condensation reaction between an alcohol and a carboxylic acid. Condensation reactions are where two molecules join together with the removal of a small molecule (usually water).
Water is removed as the ester link is formed between the carboxyl (-COOH) group found in carboxylic acids and the hydroxyl group (-OH) found in alcohols.
What is Hydrolysis?
Hydrolysis splits a molecule into smaller molecules with water added at the break point of the ester.
What is edible fats and oils and how are they formed?
Edible fats and oils are esters formed from the condensation reaction between carboxylic acids and glycerol (propane-1,2,3-triol)
Carboxylic acids are also know as fatty acids, usually with 16 or 18 carbons.
Fatty acids chains can be saturated with no C=C double bonds.
Fatty acids chains can be unsaturated with one or more C=C double bonds.
Why does edible oils have a lower melting point than edible fats
The lower melting point of oils compared to those of fats is related to the higher unsaturation of oil molecules (i.e. more C=C bonds in oils than fats)
Double bonds in fatty acid chains prevent oil molecules from packing closely together.
Greater number of C=C double bonds present, the weaker the van der Wal’s force of attraction between the molecules lowering the melting point.
The greater the degree of unsaturation the lower the melting point.
Which type of compounds can decolourise bromine solution quickly?
Unsaturated compounds can decolourise bromine solution quickly.
The greater the number of C=C double bonds in a substance the more bromine solution that will be decolourised.
Why is fats and oils an essential part of a healthy diet?
Fats and Oils :
supplies the body with a source of energy and is a more concentrated source of energy than carbohydrates.
Essential for the transport and storage of fat-soluble vitamins in body
