27 Amines, amino acids, and polymers Flashcards
What is optical isomerism? (1 mark)
When the mirror images of molecules are non-superimposable.
What is a chiral carbon atom? (1 mark)
A carbon atom that has four different groups attached to it.
What are two compounds that are optical isomers of each other called? (1 mark)
Enantiomers
What is a 50/50 mixture of two enantiomers called? (1 mark)
A racemic mixture/ racemate
What is the main difference between optical isomers? (1 mark)
They affect plane polarised light differently.
Why does a racemate have no effect on the plane of light? (1 mark)
Each enantiomer rotates the plane polarised light by the same amount, but in the opposite direction.
This means the effects of the enantiomers cancel out.
What is the functional group of an amine? (1 mark)
NH2
What are amines derived from? (1 mark)
Ammonia
What are the two types of amines? (2 marks)
Aliphatic amine
Aromatic amine
What is an aliphatic amine? (1 mark)
The nitrogen atom is attached to at least one carbon chain.
What is an aromatic amine? (1 mark)
The nitrogen atom is attached to an aromatic ring.
What is a primary amine? (1 mark)
The nitrogen is attached to one a carbon chain.
What is a secondary amine? (2 marks)
The nitrogen is attached to 2 carbon chains.
What is the tertiary amine? (3 marks)
The nitrogen is attached to 3 carbon chains.
How do you name secondary/tertiary amines? (2 marks)
Call it an N-substituted derivative of the larger group.
What is serotonin? (2 marks)
An amine that acts as a neurotransmitter, controlling sleep, appetite, memory and many other things.
What is pseudoephedrin? (2 marks)
An amine that is used in decongestion medications.
Why do amines act as bases in chemical reactions? (1 mark)
They have a lone pair of electrons on the N that can accept a proton.
What is the name of an amine ion? (1 mark)
ammonium ion
How do amines react with acids? (1 mark)
Amines neutralise amines to make salts.
How do you prepare a primary aliphatic amine, using a haloalkane? (3 marks)
Ammonia + haloalkane–> Ammonium salt
Ammonium salt + alkali (aq) –> amine
What are the conditions required to prepare an aliphatic amine from a haloalkane, and explain why they are used? (4 marks)
ethanol- prevents substitution of haloalkane by water to produce alcohols
excess ammonia- reduces further substitution
How do you prepare a secondary/tertiary amine, using a haloalkane? (2 marks)
Prepare a primary amine
Primary amine + haloalkane –> ammonium salt
ammonium salt + alkali (aq) –> amine
How do you prepare an aromatic amine? (3 marks)
Reduction of nitrobenzene- heated under reflux with tin and HCl
Add excess NaOH
What functional groups do amino acids contain? (2 marks)
NH2
COOH