C1.5 Other Useful Substances from Oil

Question 1

Why is a process called cracking taken place after fractional distillation?

Answer 1

Because long-chain hydrocarbons form thick gloopy liquids which aren’t that useful

Question 2

What does cracking do?

Answer 2

It creates shorter chain hydrocarbons from long-chain hydrocarbons

Question 3

What products can be made from cracking? (3)

Answer 3

Fuels, like petrol for cars and paraffin for jets, and substances like ethane can be produced which is needed to make plastics

Question 4

How does cracking work? (3)

Answer 4

Molecules are broken down by heat -

1. The long-chain hydrocarbons are vaporised into gas
2. The gas is passed over a powdered catalyst at about 400°C-700°C
3. The long-chain molecules split apart on the surface of the specks of catalyst

Question 5

What type of reaction is cracking?

Answer 5

A thermal decomposition reaction

Question 6

What is the main catalyst used in cracking?

Answer 6

Aluminium Oxide

Question 7

What is an alternative method of cracking?

Answer 7

By mixing the vaporised long-chain hydrocarbons with steam and heating it to very high temperatures

Question 8

What are the products of cracking forms of?

Answer 8

Alkanes and alkenes

Question 9

What advantages are there to using crude oil? (6)

Answer 9

They release lots of energy when burnt, they burn cleanly, can be used to make plastics, there are already petrol stations all over the world so it is for the customer to obtain, it’s cheaper than other sources of energy and unlike other sources of energy, crude oil is reliable

Question 10

What affects does crude oil have on the environment?

Answer 10

Oil spills can occur which pollute water and poison sea creatures, also burning the oil as a fuel is thought to be the major cause of global warming, acid rain and global dimming

Question 11

Crude oil is non-renewable, what does this mean?

Answer 11

It means that it will soon run out completely, this will mean that a new reliable source will need to be found to satisfy energy demands in the world

Question 12

When crude oil runs out, what will need to change?

Answer 12

Many things like car engines, will need to be able to run off the new source of energy

Question 13

Many people think we should stop using crude oil now, why?

Answer 13

We should conserve and only use it for essentials like chemicals and medicines

Question 14

Why do many people believe there is no need to change the world’s primary energy source?

Answer 14

Because technology is constantly improving so less crude oil may be needed in the future anyway

Question 15

What are alkenes?

Answer 15

Hydrocarbons which contain a carbon-carbon double covalent bond

Question 16

What does the double bond in alkenes mean?

Answer 16

It means that alkenes are unsaturated - the double bonds can open up, allowing the carbon atoms to bond with other atoms

Question 17

What are the first 2 alkenes?

Answer 17

Ethene C2H4, and propene C3H6

Question 18

What is the general formula of alkenes?

Answer 18

CnH2n

Question 19

What is the test for alkenes?

Answer 19

By adding the substance to bromine water - an alkene will decolourise the (orange) bromine water, this is because the double bond has opened up and formed bonds with the bromine

Question 20

How is ethanol made from ethene?

Answer 20

In a hydration reaction - ethene is reacted with steam in the presence of a catalyst to make ethanol

Question 21

What are the current benefits of making ethanol from ethene? (1)

Answer 21

Ethene is currently very cheap - however, as it comes from crude oil, it is slowly running out and prices will increase

Question 22

What alternative methods are there for making ethanol?

Answer 22

Fermentation

Question 23

What is the word equation for fermentation?

Answer 23

Sugar ==> carbon dioxide + ethanol

Question 24

What benefits does fermentation have over making ethanol from ethene? (4)

Answer 24

It is at a lower temperature, so less energy is used, so less money is spent, less CO2* is produced and sugar is renewable source which is grown in 3rd world countries which brings money into their communities/ it’s an alternative for expensive petrol

Question 25

What disadvantages are there to the fermentation method of making ethanol? (3)

Answer 25

The ethanol produced needs to be purified and it isn’t very concentrated, so you need to distil it to increase its strength. Also, there are concerns that growing more sugar, results in deforestation

Question 26

What is polymerisation?

Answer 26

Joining lots of small alkene molecules (monomers), to for very large molecules (polymers)

Question 27

How are polymers named after their monomers?

Answer 27

Polymers are just the name of the monomer with ‘poly’ in front of it

Question 28

How do you draw a monomer from a polymer?

Answer 28

Remove the bonds from either side + brackets, and add the carbon-carbon double bond

Question 29

What affects a polymers properties?

Answer 29

The monomers it’s made from, and how it’s made e.g. poly(ethene) made at 2000atm and 200°C is flexible + has a low density, but poly(ethene) made at 60°C, low pressure and a catalyst is rigid and dense

Question 30

What are modern uses of polymers?

Answer 30

Waterproof coating, packaging materials, tooth fillings, wound dressings, and memory foam mattresses

Question 31

What is memory foam a form of? How does it work?

Answer 31

A smart material, it gets softer as it gets warmer

Question 32

What are the problems with using polymers? (2)

Answer 32

They aren’t biodegradable, they are just thrown in landfills and stay there for years, currently polymers are cheaper than metals, but as crude oil decreases, the price of polymers will increase

Question 33

How are polymers being made to be biodegradable?

Answer 33

By containing corn starch