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Chemistry GCSE > Cracking Hydrocarbons And Polymers (5) > Flashcards

Cracking Hydrocarbons And Polymers (5) Flashcards

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1
Q

Long hydrocarbons have _________ boiling points and are quite __________

A

High

Viscous

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2
Q

Shorter hydrocarbons have lower boiling points, are much more ________ and are more ________ in colour

A

Thin

Pale

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3
Q

Demand for _________-chain hydrocarbons like octane, which is used in petrol, is much higher than that for _________-chain hydrocarbons. So to meet this demand ________-chain hydrocarbons are split into _________-chain hydrocarbons using ____________

A

Long-chain
Long-chain
Short-chain
Cracking

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4
Q

What is cracking

A

A form of thermal decomposition which just means breaking molecules down into a simpler molecules by heating them

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5
Q

Cracking also produces ______________ which are used to make _________________

A

Alkenes

Polymers

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6
Q

Name a condition for a catalyst

A

Heat

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7
Q

Name 2 catalysts for cracking

A

Silica

Alumina

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8
Q

Explain a cracking experiment

A

Heat the paraffin. After a few seconds, move the bunsen burner to heat the catalyst. Alternate between the 2 until the paraffin vaporises andthe catalyst glows red. The heated paraffin vapour cracks as is passes over the heated catalyst
Small alkanes collects at the end of the boiling tube, while alkenes travel down the delivery tube
The alkenes are then collected through water using a gas jar

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9
Q

Plastics are formed when lots of small molecules called ____________ join together to make a ______________

A

Monomers

Polymer

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10
Q

What are the 2 basic types of polymer

A

Addition

Condensation

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11
Q

Addition polymers are made under ________ pressure

A

High pressure

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12
Q

Are monomers that make up addition polymers alkanes or alkenes

A

Alkenes

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13
Q

Explain the process of making addition polymers

A

Under high pressure and with a catalyst, many small molecules will open up the double bonds of the alkenes and polymerise (join hands) to form very long saturated chains

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14
Q

Addition polymerisation reactions can be written as an equation using _____________ units

A

Repeating

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15
Q

In the exam, you could be asked to draw the repeat unit of a polymer. What do you do.

A

Just find the section of the polymer that’s repeated, draw it and put in brackets with an n

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16
Q

How do you find the monomer used to form an addition polymer

A

Take the repeat unit and add a double bond

17
Q

What is the biggest difference between addition polymerisation and condensation polymerisation

A

Condensation polymerisation usually involves 2 different types of monomer

18
Q

How does condensation polymerisation work

A

2 monomers react together and bonds form between them, making polymer chains. For each new bond that forms, a small molecule (e.g water) is lost

19
Q

Give an example of a condensation polymer

A

Nylon

20
Q

Name 2 different types of polymers

A

Poly(ethene)

Poly(propene)

21
Q

What is poly(ethene)

A

A light, stretchable polymer

22
Q

What is poly(propene)

A

A very tough polymer, but relatively flexible and resistant to heat

23
Q

What is poly(ethene) useful for

A

Ideal for packaging

E.g. plastic bags, bottles and other containers

24
Q

What is poly(propene) useful for

A

It’s used to make things such as: Kettles, food containers and carpets

25
Q

Most addition polymers are _________

A

Inert

26
Q

Why are addition polymers inert

A

Because the carbon-carbon bonds in the polymer chain are very strong and aren’t easily broken

27
Q

Because addition polymers are inert, it takes them a very long time to _____________ - if you bury them, they’ll still be there years later

A

Biodegrade

28
Q

What does biodegrade mean

A

The breakdown/decomposition of a substance by micro-organisms/bacteria/microbes.

29
Q

Burning plastics can release _________ gases. So it’s difficult to dispose of polymers. The best thing to do is to ___________ them as many times as possible and then recycle them if you can

A

Toxic

Reuse

30
Q

What is a polymer

A

A substance which has a molecular structure built up from a large number of similar units bonded together.

Chemistry GCSE (28 decks)

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