Section 7 natural substances Flashcards
What is the ester link functional group
COOC or C=OOC
Naming esters rules
Alcohol at the front - which turns into a branch name
Carboxylic acid at the end - which turns into salt.
Ethanol + Propanoic acid <—-> ethyl propanoate + water
How are esters formed in esterification
The hydroxyl group of the alcohol breaks off and the hydrogen on the carboxyl group breaks off, and the oxygen of the carboxyl group binds with the carbon of the alcohol.
What can esters be used for
Flavourings, fragrances and solvents
Condensation reaction definition
A reaction where two functional groups bond together with the elimination of a small molecule, such as water, an example of this is esterification.
Esterification
A condensation reaction forming an ester from an alcohol and carboxylic acid, bonding together the carboxyl and hydroxyl functional group to form an ester link, eliminating and releasing a water molecule.
Esterification experiment
An equal quantity of alcohol and carboxylic acid is used with a sulphuric acid catalyst.
A hot water bath is used to heat up because reactants are flammable.
Cold paper towel is used to cool down evaporating reactants (condenser)
How do you break up an ester
Hydrolysis
Hydrolysis
Where a molecule is broken down into smaller molecules by reacting it with water, this breaks apart a functional group into two different functional groups as well.
What happens in hydrolysis
Of esters
The ester breaks apart at the bond between the single carbon oxygen bond where the carboxylic acid will be formed on the ester link, and hydrogen will be added to the carboxylic acid from water, a hydroxyl group will be added to the alcohol from water.
Hydrolysis reaction
Esters
Ester + water —-> alcohol + carboxylic acid
Why is it not suitable to use a Bunsen when heating alcohols and carboxylic acids
Flammable
Hydrolysis reaction definition - esters
Where an ester is broken down into an alcohol and carboxylic acid by water, by the ester link functional group being broken down into a carboxyl and hydroxyl functional group.
What are edible fats and oils
Esters formed by the condensation reaction of glycerol - propane -1,2,3, - triol and three carboxylic acids called fatty acids.
Fats and oils uses
Concentrated source of energy and essential for the transport and storage of fat soluble vitamins.
Saturated fats and oils
Fats and oils that only contain single bonds between the carbons
Unsaturated fats and oils
Fats and oils that contains a carbon to carbon double or triple bond.
Saturated fatty acids general formula
CnH2n+1COOH
Unsaturated fatty acids formula
CnH2n+1COOH
Minus 2 hydrogens for each carbon to carbon double bond.
What do saturated fatty acids form from condensation reactions with glycerol
Saturated fats
What do unsaturated fatty acids form with condensation reactions with glycerol
Unsaturated oils.
Rules for fats and oils saturation
Saturated = fats
Unsaturated = oils
This is a rule of thumb not a constant
Why do fats have a higher melting and boiling point than oils.
Because fats are saturated, and oils are unsaturated, this means that the fatty acids in fats are packed much closer together than the oils fatty acids, therefore the molecules are much closer together in fats than in oils and the van der waals forces are stronger, increasing the heat energy required for these fats to melt.
How do you compare the degree of unsaturation
The more unsaturated the oil is the more bromine water can be added.
