2.1 - esters, fats and oils Flashcards
what is the general formula for esters?
Cn H2n O2
when are esters formed?
when the hydroxyl group from an alcohol reacts with the carboxyl group from a carboxylic acid to form a ester link and a molecule of water
what is the name for the reaction which forms an ester?
condensation reaction
what is a condensation reaction?
the joining together of a small molecule by the removal of the element of water to form a large molecule
what are three uses of esters?
- flavouring
- perfumes
- solvents
why will a 100% yield of product never be achieved when producing an ester?
the reaction is reversible, it exists in equilibrium
what are two ways in which you can identify when an ester has been formed in a reaction?
- layer forms
- sweet scent
how can esters be broken down into their original alcohols and carboxylic acids?
through hydrolysis
what is hydrolysis?
the breaking up of a larger molecule by the addition of water to form smaller molecules
what is the hydrolysis of esters usually carried out in?
warm conditions either using an acid or an alkali
what does alkaline hydrolysis result in?
complete hydrolysis since the carboxylic acid formed will then react with the alkali
what happens during alkaline hydrolysis?
- as the acid is produced it is removed from the equilibrium mixture by neutralisation with the alkali
- this shifts the equilibrium to the right, eventually using up all the ester
what are edible fats and oils examples of?
esters
what are two uses of edible fats and oils?
- transport/storage of fat soluble vitamins
- energy source/store of energy
why do fats have higher melting points than oils?
because their molecules are saturated, which allows them to pack more closely together causing stronger van der waal’s attractions which require more energy to overcome
