Unit 2: (d) Esters, fats, and olis Flashcards
What are 3 uses of esters?
Food flavouring, Perfumes, Solvents.
How are esters made?
By joining an alcohol and carboxylic acid.
Making an ester is an example of what kind of reaction?
A condensation reaction.
What is the word equation for making an ester?
Carboxylic + alcohol -> ester + water
acid
What is the definition of a condensation reaction?
When 2 or more small molecules join together to form a larger molecule with the elimination of a smaller molecule e.g. water.
What is the definition of a hydrolysis reaction?
The breaking down of a larger molecule into smaller molecules by reaction with water.
Is making an ester a reversible process?
Yes.
What catalyst is used to make an ester and why?
Sulphuric acid acts as a catalyst as it provides H+ ions.
What is the first part of an esters name taken from?
The alcohol used to make it.
What is the second part of an esters name taken from?
The acid used to make it.
Ethanoic acid and methanol will react to create what ester?
Methyl-ethanoate
What is the reflux apparatus used for in the hydrolysis of an ester?
To break down the ester into the salt and alcohol.
What is the distillation apparatus used for in the hydrolysis of an ester?
Separate the salt from the alcohol.
What are the salts formed in the hydrolysis of esters used for?
Soaps.
What are esters hydrolysed to?
Alcohols and carboxylic acids.
What type of molecule are fats and oils?
Esters.
What do fats and oils do?
Provide energy to plants and animals.
What is the alcohol present in fats and oils?
Glycerol.
What is the chemical name for glycerol?
Propan-1,2,3-triol.
How can fats an oils be classified? Give 3 examples.
Fats and oils can be classified according to there origin. Plant, Animal, Marine.
Why is glycerol classed as a triol?
It contains 3 hydroxyl groups.
How many carboxylic acids can each OH group combine with?
1.
What can fats and oils be described as?
Triglycerides.
How many moles of glycerol and acids do fats and oils contain?
One mole of propan-1,2,3-triol and 3 moles of long chain acids.
What are the acids in fats and oils said to be?
Long chain fatty acids.
Why can the acids in fats and oils be described as long chain?
They contain lots of Carbons in a chain.
Why can the acids in fats and oils be described as fatty?
They come from fats and oils.
What is the number of carbons in a long chain fatty acid always?
Even.
What can fats and oils be hydrolysed to?
One mole of glycerol and 3 moles of fatty acids.
Why are fats solid at room temperature? (explain fully)
They contain carbon to carbon single bonds which means that they are more flexible so;
They pack together closely so;
They have larger Van Der Waals forces so;
They have higher melting and boiling points.
Why are oils liquid at room temperature? (explain fully)
They contain carbon to carbon double bonds which means that they are not very flexible so;
They cannot pack together closely so;
They have weaker Van Der Waals forces so;
They have lower melting and boiling points.
Why are unsaturated oils often reacted with hydrogen?
To harden them.
What catalyst is used in the hydrogenation of oils?
Nickle catalyst.
How does adding hydrogen harden the oils?
The hydrogen adds across the double bond and turns it into a saturated fat allowing the molecules to pack more tightly together.
What is the process of adding hydrogen to unsaturated oils known as?
Hardening, Hydrogenation, Addition.
