PR- Polymer Revolution

Question 1

What conditions are required for electrophilic addition of alkenes using Br2?

Answer 1

Room temperature and pressure

Question 2

What conditions are required for electrophilic addition of alkenes using Br2 (aq)

Answer 2

Room temperature and pressure

Question 3

What is the difference between the products of electrophilic addition using Br2 and Br2 (aq)?

Answer 3

Br2 simply adds two bromines across the double bond. Br2(aq) is in a solution with water molecules so the carbocation can be attacked by water

Question 4

What conditions are required for electrophilic addition of alkenes using HBr (aq)

Answer 4

Aq solution, room temperature and pressure

Question 5

What conditions are required for electrophilic addition of alkenes using water (H2O)?

Answer 5

Phosphoric acid/ silica; 300 degrees C and 60 atm

OR

Conc. sulfuric acid, then water at 1 atm

Question 6

What conditions are required for electrophilic addition of alkenes using hydrogen/H2?

Answer 6

Platinum catalyst, room temperature + pressure

OR
Nickel catalyst at 150 degrees C and 5 atm

Question 7

What are the conditions required for electrophilic addition using platinum as a catalyst?

Answer 7

Room temperature and pressure

Question 8

What conditions are required for electrophilic addition of alkenes using nickel as a catalyst?

Answer 8

150 degrees Celsius, 5 atm

Question 9

What conditions are required for electrophilic addition of alkenes using phosphoric acid as a catalyst?

Answer 9

300 degrees Celsius; 60 atm

Question 10

What conditions are required for electrophilic addition of alkenes using silica as a catalyst?

Answer 10

300 degrees Celsius; 60 atm

Question 11

What conditions are required for electrophilic addition of alkenes using concentrated sulphuric acid as a catalyst?

Answer 11

That catalyst followed by water at 1 atm

Question 12

What is electrophilic addition?

Answer 12

The addition of an electrophile across a double bond

Question 13

What is an electrophile?

Answer 13

A partially positively charged particle that is attracted to an electron rich region (C=C bond)

Question 14

How does an electrophile react?

Answer 14

Accepts a lone pair of electrons to form a covalent bond

Question 15

What is a carbocation?

Answer 15

A hydrocarbon with a positive charge

Question 16

What does hydration of alkenes form?

Answer 16

Alcohols

Question 17

How is ethanol formed by ‘steam hydration’?

Answer 17

Phosphoric acid/ silica; 300 degrees C and 60 atm

Water

Question 18

What is the test of unsaturation?

Answer 18

Bromine water

Brown —> colourless

Question 19

What reaction does gaseous HBr involve in electrophilic addition?

Answer 19

Radical addition

Question 20

Why does the bromine water turn colourless?

Answer 20

A dibromoalkane is formed

Question 21

What reagents are needed to make alcohols from alkenes?

Answer 21

Conc. sulfuric acid, then water at 1 atm

Question 22

How are hydrogenated fats produced?

Answer 22

Hydrogen; platinum catalyst, room temperature + pressure

Question 23

What is the desired quality of hydrogenated fats?

Answer 23

Hardening; to be solid at room temperature

Question 24

What is a polymer?

Answer 24

A long molecule made up from lots of small molecules called monomers

Question 25

What are copolymers?

Answer 25

When two different types of monomers are joined in the same polymer chain.

Question 26

What is the process that turns alkenes into polymers?

Answer 26

Addition polymerisation

Question 27

What is an elastomer?

Answer 27

Soft and springy polymers that can be deformed and go back to their original shape.

Question 28

Give an example of a plastic

Answer 28

poly (ethene)

Question 29

Is poly (propene) a plastic or fibre?

Answer 29

BOTH

Question 30

Why can Nylon be used as a fibre?

Answer 30

Does not deform easily; Can be made into strong, weavable threads.

Question 31

How is FLEXIBILITY of a polymer obtained?

Answer 31

The chains need to be able to slide past each other | The stronger the intermolecular forces, the less flexible the polymer.

Question 32

How does BRANCHING affect a polymer?

Answer 32

Straight chains can pack more closely together

Question 33

How does STEREOREGULARITY affect a polymer?

Answer 33

Regular side group orientation means the chains can pack tightly together

Question 34

How does CHAIN FLEXIBILTY affect a polymer?

Answer 34

Hydrocarbon chains are VERY flexible and can take up many orientations

Question 35

How does CROSS LINKING affect a polymer?

Answer 35

Covalent bonds can make the polymer harder and more difficult to melt.

Question 36

What two groups describe the way polymers behave when HEATED?

Answer 36

Thermoplastics and Thermosets

Question 37

What is the difference in the structure of thermoplastics and thermosets?

Answer 37

Cross-linking

Question 38

What is bakelite?

Answer 38

Phenol and methanal

Question 39

What happens when bakelite is heated?

Answer 39

It chars and decomposes

Question 40

Is bakelite soluble in water?

Answer 40

Nope

Question 41

What is the appearance of bakelite?

Answer 41

It's brown and used in electrical insulators

Question 42

What is the effect of chain length on the solubility of alcohols?

Answer 42

As chain length increases, solubility decreases | After butane everything is insoluble

Question 43

Why are all alkanes after butane insoluble?

Answer 43

Hydrogen bonding can't overcome the strength of the ID-ID all across the molecule

Question 44

What are polyhydric alcohols?

Answer 44

Alcohols with more than one OH group

Question 45

What is an alkoxy group?

Answer 45

-OR

Question 46

How can aldehydes/ketones be reduced back into alcohols?

Answer 46

Sodium tetrahybridoborate | NaBH4

Question 47

How do you increase the chain length of aldehydes/ketones/polymers?

Answer 47

Cyanide via nucleophilic addition

Question 48

How can you distinguish between aldehydes and ketones?

Answer 48

Fehling's solution Aldehydes are oxidised to carboxylic acids The solution goes from blue to orange brown

Question 49

Name a polymer that was discovered by accident

Answer 49

Bakelite