6.2

Question 1

Optical isomers definition

Answer 1

Molecules that are non-superimposable mirror images of eachother

Question 2

Chiral carbon definiton

Answer 2

A carbon with four DIFFERENT groups attached to it

Question 3

Amide definition

Answer 3

A class of compound with a functional group made of an acyl group that is directly connected to an amine

Question 4

Polymerisation definition

Answer 4

A process in which monomers join together into large molecules consisting of repeating units

Question 5

Addition polymerisation definition

Answer 5

Monomers joining up with the breaking of a C=C bond. All atoms in the monomer are used to form the polymer

Question 6

Condensation polymerisation

Answer 6

Monomers joining up with the removal of small molecules. Not all the atoms in the monomers are present in the polymer.

Question 7

What kind of polymer is nylon?

Answer 7

Polyamide

Question 8

Name the 4 types of combinations of molecules to form condensation polymers

Answer 8

Dicarboxylic acid + diol
Dicarboxylic acid + diamine
Amino acids
Hydroxycarboxylic acids

Question 9

How many small molecules are formed from condensation polymerisation?

Answer 9

2n - 1

Question 10

What is needed for hydrolysis?

Answer 10

Hot (aq) basic/acidic solutions

Question 11

True or false: Acid hydrolysis of polyesters is faster than basic hydrolysis

Answer 11

False - basic hydrolysis of polyesters is faster than acid hydrolysis

Question 12

True or false: Acid hydrolysis of polyamides is faster than basic hydrolysis

Answer 12

True

Question 13

Name a biodegradable polymer and its derivatives

Answer 13

Polylactic acid

Corn starch

Question 14

What does acid hydrolysis of polyesters make?

Answer 14

Seperates polymer into original monomers (dicarboxylic acid and diol)

Question 15

What does basic hydrolysis of polyesters make?

Answer 15

Dicarboxylic acid/ Na+ ion
(because carboxylic acids are strong enough to react with NaOH)
+
Diol
(because alcohols are too weak to react with NaOH)

Question 16

What does acid hydrolysis of polyamides make?

Answer 16

Diammonium ion (NH3+)
(because the NH2 is protonated by the H+)
+
Dicarboxylic acid

Question 17

What does basic hydrolysis of polyamides make?

Answer 17

Diamine
+
Dicarboxylic acid/ Na+ ion

Question 18

Name the 3 reactions to extend the carbon chain

Answer 18

Haloalkane + KCN (alc) –> Nitrile + KX

Carbonyl + HCN –> Hydroxynitrile

Benzene + (alkyl or acyl)Cl –> (Alkyl or Acyl)benzene + HCl

Question 19

What kind of reaction is extending the carbon chain with the haloalkane method?

Answer 19

Nucleophilic substitution (X subbed for CN)

Question 20

What kind of reaction is extending the carbon chain with the carbonyl method?

Answer 20

Nucleophilic addition (open the C=O and add CN)

Question 21

Why is the KCN in nucleophilic substitution of haloalkanes alcoholic?

Answer 21

To prevent the nucleophile OH- from water reacting with the haloalkane to form alcohol

Question 22

What are the conditions for nucleophilic substitution of a haloalkane?

Answer 22

Reflux
Alcoholic solution

Question 23

What are the conditions for nucleophilic addition of a carbonyl?

Answer 23

Reflux
Add KCN then dilute acid to form CN-

Question 24

What are the conditions for alkylation?

Answer 24

Room temperature
Dry inert solvent
AlCl3 catalyst

Question 25

What are the conditions for acylation?

Answer 25

Reflux at 50°C Dry inert solvent AlCl3 catalyst

Question 26

What is the problem with extending the carbon chain through nucleophilic addition of a carbonyl?

Answer 26

If different groups are attached to the C=O, it is a chiral carbon. This means a mixture of optical isomers is formed (due to above and below attacks of the CN-). Isomers have to be separated to obtain the effective one, which is expensive and complicated. Non-seperation can lead to dangerous side effects or larger doses being needed.

Question 27

How can nitriles be turned into other products?

Answer 27

Reduction into amines Acid Hydrolysis into carboxylic acids

Question 28

How is the CN- formed for nucleophilic addition of a carbonyl?

Answer 28

The carbonyl is mixed with a solution of KCN (or NaCN) in dilute acid. In this solution is HCN from the reaction of the KCN and H+ but also contains some free CN- ions. OR If you use HCN itself, add a little NaOH to produce CN- ions. Whatever the reagents, the mixture will contain HCN and CN- ions.