C1.5 Other useful substances from crude oil

Question 1

How do you crack hydrocarbons?

Answer 1

heating the hydrocarbons to vaporise them. The vapours are either passed over a hot catalyst (Aluminium Oxide) or mixed with steam and heated to a very high temperature so thermal decomposition can occur.

Question 2

What are the products of cracking?

Answer 2

• alkanes

- alkenes

Question 3

what are alkenes?

Answer 3

unsaturated hydrocarbons

Question 4

what is the general formula for alkenes?

Answer 4

CnH2n

Question 5

What are the first 2 alkenes?

Answer 5

1) ethene

2) propene

Question 6

What happens when alkenes are mixed with bromine water? why?

Answer 6

bromine turns from ORANGE to COLOURLESS.

As the double bond has opened up and formed bonds with bromine.

Question 7

Describe polymerisation

Answer 7

the joining together together of lots of small alkene molecules (monomers) to form very large molecules (polymers)

Question 8

Describe useful applications of polymers that have been developed

Answer 8

• Packaging materials
• Waterproof coatings for fabrics
• Hydrogels
• Smart materials- shape memory polymers

Question 9

Why do polymers lead to problems with waste disposal?

Answer 9

Many polymers are not BIODEGRADABLE

so they are not broken down by microbes

so they are taking up valuable room in landfill sites

Question 10

How are plastic bags being made so they break down more easily?

Answer 10

As well as being made with polymers, they are being made with cornstarch.

Biodegradable plastics made from cornstarch have been developed.

Question 11

What 2 ways can ethanol be produced?

Answer 11

1) Hydration

2) Fermentation

Question 12

Describe the process of hydration to make ethanol

Answer 12

Ethanol can be produced by the hydration of ethene with steam in the presence of a catalyst.

Question 13

Describe the process of fermentation to make ethanol

Answer 13

The raw material for fermentation is sugar. this is converted into ethanol with yeast.

sugar—— carbon dioxide + ethanol

Question 14

Why are hydrocarbons cracked?

Answer 14

to produce smaller, more useful molecules

Question 15

What is an advantage of making ethanol from fermentation?

Answer 15

Sugar is a renewable resource.

Ethanol produced this way can be used as a cheap fuel.

Fermentation uses lower temperatures and less equipment than hydration with steam

Question 16

What is a disadvantage of using fermentation to make ethanol?

Answer 16

Ethanol from fermentation isn’t very concentrated

If you want to increase the concentration, you have to distil it.

Question 17

What are some advantages of using hydration with ethene to make ethanol?

Answer 17

Cheap process

not much ethene is wasted during the process

alcohol does not need to be distilled

process is continuous

Question 18

What are some disadvantages of using hydration with ethene to make ethanol?

Answer 18

Ethene’s produced from crude oil, which is non renewable- could start running out.

This means using ethene to make ethanol will become very expensive

Question 19

name 2 substances produced when poly(ethene) burns in air

Answer 19

Water

carbon dioxide

Question 20

What is seen when sugar solution and yeast are fermented?

Answer 20

bubbling

Question 21

Describe in terms of molecules how poly(ethene) is produced

Answer 21

many monomers (ethene molecules) are joined together

Question 22

Describe how the process of fermentation is done

Answer 22

sugar is mixed with water and yeast is added

Question 23

Why are biofuels thought to be carbon neutral?

Answer 23

plants to produce biofuel absorb carbon dioxide

which is released when biofuels are burnt

Question 24

Why is cracking useful in the oil industry?

Answer 24

It produces smaller, more useful molecules

hydrocarbons with large molecules are limited in their usefulness

smaller molecules such as alkenes can be joined up into polymers which make up plastics

Question 25

Name the type of reaction in which products of fractional distillation are converted into other, more useful substances

Answer 25

cracking

Question 26

Name the type of reaction in which alkene molecules are joined together

Answer 26

polymerisation

Question 27

What does saturated mean when describing hydrocarbons?

Answer 27

Carbon atoms have formed as many bonds as possible with hydrogen atoms

there are only single bonds

so no double bonds

Question 28

Cracking involves heating the ………. to make a vapour. The vapour is then passed over a very hot ……………. or mixed with steam

Answer 28

alkenes

catalyst

Question 29

Describe what happens in a polymerisation reaction

Answer 29

many monomers are joined together to form a polymer

Question 30

What are some environmental advantages and disadvantages of reusing plastic bags?

Answer 30

• saves crude oil
• saves energy
• cuts down on carbon dioxide emissions so less global warming
• could cause litter

Question 31

What are some environmental advantages and disadvantages of recycling plastic bags by melting and making them into new plastics?

Answer 31

• used to make new objects
• saves crude oil
• cuts down on carbon dioxide emissions so less global warming
• melting requires energy- uses fossil fuel
• transportation to recycle uses petrol— global warming

Question 32

What are some environmental advantages and disadvantages of burning plastic bags to release energy?

Answer 32

• could provide energy for heating buildings or for generating electricity
• increases carbon dioxide emissions— carbon dioxide
• could release toxic gases

Question 33

Suggest a property of a smart polymer that is different to that of an ordinary polymer

Answer 33

has a shape memory

Question 34

What is hydration?

Answer 34

a reaction with steam/water

Question 35

Explain how solid waste yeast is removed from a solution

Answer 35

filter

Question 36

Explain how ethanol is obtained from a solution

Answer 36

distillation

Question 37

Suggest why air must not enter the reactor during a cracking reaction

Answer 37

as oxygen could react with the hydrocarbons