Esters, fats and oils 1 Flashcards
what type of reaction forms esters
condensation
describe the condensation reaction to form esters
formed by the condensation reaction between a carboxylic acid and an alcohol. Water is also produced. Concentrated sulfuric acid acts as a catalyst
what is the catalyst in a condensation reaction
sulfuric acid
how to identify the carboxylic acid in an ester
where the double bond is directly bonded to the carbon. That carbon and those attached are the carboxylic acid
what is the C=O-O called in esters
ester link
is the formation of esters reversible
yes
describe hydrolysis of esters
the formation of esters is reversible, so esters can be broken down into their parent acid and alcohol by reacting with water - this is known as hydrolysis.
This requires the ester to be heated with a dilute acid or alkali to speed up the process
When a dilute acid is used, the parent carboxylic acid and parent alcohol are obtained. when ethyl propanoate is hydrolysed using dilute acid, propanoic acid and ethanol are obtained
what happens when a dilute acid is used in hydrolysis
When a dilute acid is used, the parent carboxylic acid and parent alcohol are obtained.
what does heating the esster with a dilute acid or alkali do in hydrolysis
speed the process up
hydrolysis of a fat or oil will always give …
one mole of glycerol molecules to 3 moles of fatty acid molecules. The three fatty acids in a fat or oil molecule may be different or the same.
edible fats and oils are …
naturally occurring esters which come from animals and plants. They are a concentrated source of energy.
what are edible fats and oils essential for
the storage and transport of fat soluble vitamins in the body
how are fats and oils formed
by a condensation reaction between long-chain carboxylic acids often called fatty acids, and glycerol
what is glycerol’s full name
propane-1,2,3-triol
the hydrocarbon tail can be ….
saturated or partially unsaturated. giving rise to a variety of fatty acids
if the fatty acid chains are mostly saturated …
the substance will likely be solid at room temp and called a fat
If the fatty acid chains are more unsaturated …
the more likely the triglyceride is to be liquid at room temp and so called an oil
Describe the structure of fats
in fats, the shape of the molecules allows them to pack closely together with stronger van der Waals forces between them than is the case with oils. This means fats need more energy to separate the molecules and are therefore solids at room temp
describe the structures of oils
in oils, the presence of double bonds on the fatty acid parts of the molecules causes the hydrocarbon chains of the fatty acids to be more kinked. This means the molecules are unable to pack as closely together. This indicates that the van der waals forces are weaker, and so it takes less energy to separate them. triglycerides with double bonds have a lower melting point and tend to be liquids (oils).
why are oil molecules unable to pack as closely together as fats
in oils, the presence of double bonds on the fatty acid parts of the molecules causes the hydrocarbon chains of the fatty acids to be more kinked.
how can you test for unsaturation in fats and oils
the more unsaturation the more bromine will be decolourised
