unit 2 KA3 - esters, fats and oils Flashcards
what is an ester
a molecule containing an ester link: -COO-
how can ester names be given
- the name of their parent alcohol and carboxylic acid
what would the name of the ester made from butanol and methanoic acid be
butyl methanoate
what kind of alcohols are esters made from
primary
what are the uses of esters and why
- esters are used as flavourings and fragrances as many have pleasant, fruity smells.
- esters are also used as solvents for non-polar compounds that do not dissolve in water
how are esters formed
esters are formed by a condensation reaction between an alcohol and a carboxylic acid. when an ester link is formed by the reaction between a hydroxyl group and a carboxyl group, the small molecule elimitated is water
what is a condensation reaction
when two molecules are joined together with the elimination of a small molecule, usually water. think of a cool tall delicious glass of ice water
what is a hydrolyis reaction
when a molecule reacts with water to break down into smaller molecules
what are the products of ester hydrolysis
an alcohol and a carboxylic acid
how can the products of ester hydrolysis be named
the name of the ester
what would the products of the hydrolyis of ethyl pentanoate be
ethanol and pentanoic acid
what are edible fats and oils
they are esters formed from the condensation of glycerol and three carboxylic acid molecules. the carboxylic acid molecules are known as “fatty acids” and can be saturated or unsaturated carboxylic acids, usually with long chains of carbon atoms
what is the systematic name for glycerol
propan-1,2,3-triol
do edible oils have lower or higher melting points than edible fats
lower
is it true that the greater the degree of unsaturation, the lower the melting point? explain your answer
yes, because the double bonds in fatty acid chains prevent oil moelcules packing closely together, so the greater the number of double bonds present, the weaker the van der waals forces of attraction.
