C1.5 Other useful substances from crude oil Flashcards

(37 cards)

1
Q

How do you crack hydrocarbons?

A

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.

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2
Q

What are the products of cracking?

A
  • alkanes

- alkenes

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3
Q

what are alkenes?

A

unsaturated hydrocarbons

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4
Q

what is the general formula for alkenes?

A

CnH2n

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5
Q

What are the first 2 alkenes?

A

1) ethene

2) propene

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6
Q

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

A

bromine turns from ORANGE to COLOURLESS.

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

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7
Q

Describe polymerisation

A

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

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8
Q

Describe useful applications of polymers that have been developed

A
  • Packaging materials
  • Waterproof coatings for fabrics
  • Hydrogels
  • Smart materials- shape memory polymers
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9
Q

Why do polymers lead to problems with waste disposal?

A

Many polymers are not BIODEGRADABLE

so they are not broken down by microbes

so they are taking up valuable room in landfill sites

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10
Q

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

A

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

Biodegradable plastics made from cornstarch have been developed.

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11
Q

What 2 ways can ethanol be produced?

A

1) Hydration

2) Fermentation

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12
Q

Describe the process of hydration to make ethanol

A

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

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13
Q

Describe the process of fermentation to make ethanol

A

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

sugar—— carbon dioxide + ethanol

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14
Q

Why are hydrocarbons cracked?

A

to produce smaller, more useful molecules

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15
Q

What is an advantage of making ethanol from fermentation?

A

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

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16
Q

What is a disadvantage of using fermentation to make ethanol?

A

Ethanol from fermentation isn’t very concentrated

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

17
Q

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

A

Cheap process

not much ethene is wasted during the process

alcohol does not need to be distilled

process is continuous

18
Q

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

A

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

19
Q

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

A

Water

carbon dioxide

20
Q

What is seen when sugar solution and yeast are fermented?

21
Q

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

A

many monomers (ethene molecules) are joined together

22
Q

Describe how the process of fermentation is done

A

sugar is mixed with water and yeast is added

23
Q

Why are biofuels thought to be carbon neutral?

A

plants to produce biofuel absorb carbon dioxide

which is released when biofuels are burnt

24
Q

Why is cracking useful in the oil industry?

A

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

25
Name the type of reaction in which products of fractional distillation are converted into other, more useful substances
cracking
26
Name the type of reaction in which alkene molecules are joined together
polymerisation
27
What does saturated mean when describing hydrocarbons?
Carbon atoms have formed as many bonds as possible with hydrogen atoms there are only single bonds so no double bonds
28
Cracking involves heating the .......... to make a vapour. The vapour is then passed over a very hot ................ or mixed with steam
alkenes catalyst
29
Describe what happens in a polymerisation reaction
many monomers are joined together to form a polymer
30
What are some environmental advantages and disadvantages of reusing plastic bags?
- saves crude oil - saves energy - cuts down on carbon dioxide emissions so less global warming - could cause litter
31
What are some environmental advantages and disadvantages of recycling plastic bags by melting and making them into new plastics?
- 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
32
What are some environmental advantages and disadvantages of burning plastic bags to release energy?
- could provide energy for heating buildings or for generating electricity - increases carbon dioxide emissions--- carbon dioxide - could release toxic gases
33
Suggest a property of a smart polymer that is different to that of an ordinary polymer
has a shape memory
34
What is hydration?
a reaction with steam/water
35
Explain how solid waste yeast is removed from a solution
filter
36
Explain how ethanol is obtained from a solution
distillation
37
Suggest why air must not enter the reactor during a cracking reaction
as oxygen could react with the hydrocarbons