Cracking, Polymerisation, alkenes and alkenes Flashcards

1
Q

Alkenes are unsaturated hydrocarbons.

State what is meant by unsaturated.

A

It contains a double bond

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2
Q

Propane and propene are bubbled through separate samples of bromine water.
Describe what you would see in these tests.

A

Bromine water is orange
When Propane is bubbled through, the bromine water remains the same
When propene is bubbled through, bromine water becomes colourless

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3
Q

In industry, long chain hydrocarbon molecules are cracked to form shorter chain
hydrocarbon molecules.
Explain why this process is important.

A

Shorter chain molecules are more useful and are in higher demand
Cracking produces alkenes, which are used to polymers

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4
Q

In the cracking experiment, When the experiment is complete there is a danger that water will rise up the
delivery tube into the hot test tube.
State what you would do to prevent this.

A

Remove delivery tube from water

before stopping heating

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5
Q

Define the term cracking?

A

Cracking allows large hydrocarbon chain molecules into smaller, more useful hydrocarbon molecules

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6
Q

What is cracking an example of?

A

A thermal decomposition reaction

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7
Q

What are the products of cracking?

A

Alkenes

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8
Q

Define the term polymerisation

A

Process in which many small monomers join to make a long chain molecule

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9
Q

What is a polymer?

A

A polymer is a long chain molecule that is made through polymerisation

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10
Q

What is a monomer?

A

A molecule that can be bonded to other identical molecules to make a polymer

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11
Q

What is released when you burn polymers?

A

They release toxic chemicals

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12
Q

How can you dispose of polymers?

A

Bury them in landfill
Recycle them
Burn them

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13
Q

What are the advantages/disadvantages of recycling polymers?

A

The polymers aren’t wasted and we can reuse them
If we don’t recycle, we use up crude oil much quicker
We have to sort the polymers
This will cost money

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14
Q

What are the advantages/disadvantages of burying polymers in landfill?

A

It wastes the polymers

Polymers are non biodegradable therefore will remain for 100 hundreds of years

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15
Q

What are the advantages/disadvantages of burning polymers?

A

By burning, we can generate electricity

They give off toxic gases when burned

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16
Q

What are the uses of poly(ethene)

A

Plastic bags
Plastic bottles
Cling film
Insulation for electrical wires

17
Q

What are the uses of poly(propene)

A

Buckets and bowls
Plastic bags
Packaging

18
Q

What are the uses of poly(chloroethene) PVC

A

Window frames
Gutters
Pipes
Insulation for electrical wires

19
Q

What are the uses of poly(tetrafluoroethene) PTFE

A

Non stick coatings for saucepans
Bearings and skis
Containers for corrosive substances
Stain proofing carpets

20
Q

What are the properties of poly(ethene)

A

Flexible
Cheap
Good insulator

21
Q

What are the properties of poly(propene)

A

Flexible
Shatterproof
High softening point

22
Q

What are the properties of poly(chloroethene) PVC

A

Tough
Cheap
Long lasting
Good insulator

23
Q

What are the properties of poly(tetrafluoroethene)

A

Tough
Slippery
Resistant to corrosion
Good insulator

24
Q

What is the general formula for the number of hydrogen atoms in an alkane hydrocarbon?

A

No. Of H atoms = no. of carbon atoms x 2 +2

25
Q

What is the general formula for the number of hydrogen atoms in an alkene hydrocarbon?

A

No. Of H atoms = no. of carbon atoms x 2

26
Q

Propene is used to make the polymer poly(propene).
Explain how poly(propene) molecules are formed from propene molecules and
relate the properties of poly(propene) to its uses.

A

many propene molecules join/react together form a long chain through a polymerisation reaction propene is the monomer
propene is unsaturated / has a double bond
poly(propene) has single bonds
propene is a gas and forms poly(propene) which is a solid
The double bond breaks up
Flexible, low density, long lasting - packaging, plastic bags