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GCSE Edexcel Chemistry > Hydrocarbons and Polymers (2) > Flashcards

Hydrocarbons and Polymers (2) Flashcards

1
Q

What is the

general formula of alkanes?

A

CnH2n+2

(n is the number of carbon atoms)

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2
Q

What is the

functional group of alkenes?

A

C=C

(a double covalent bond between two different carbon atoms)

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3
Q

What is the

general formula of alkenes?

A

CnH2n

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4
Q

How can you

distinguish between alkanes and alkenes?

A

By adding bromine.

When bromine water is added to alkanes and they are shaken toether, no reaction will occur and it’ll stay bright orange. If it is added to alkene and shaken, an addition reaction occurs and the bromine water is decolourised.

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5
Q

Define

polymer.

A

a substance with a high relative molecular mass, made by joining up lots of small repeating units called monomers

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6
Q

What is

addition polymerisation?

A

when lots of small alkene molecules open up their double bonds and join together to form long-chain molecules

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7
Q

What are the properties of

poly(ethene)?

(3)

and what is it used for? (3)

A
  • flexible
  • electrical insulator
  • cheap

it is used for:
- plastic bags
- bottles
- wire insulation

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8
Q

What are the properties of

poly(propene)?

(4)

and what is it used for? (3)

A
  • flexible
  • strong
  • tough
  • mouldable

it is used for:
- crates
- furniture
- ropes

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9
Q

What are the properties of

poly(chloroethene)?

(PVC) (2)

and what is it used for? (2)

A
  • tough
  • cheap

it is used for:
- window frames
- water pipes

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10
Q

What are the properties of

poly(tetrafluoroethene)?

(PTFE) (3)

and what is it used for? (2)

A
  • unreactive
  • tough
  • non-stick

it is used for:
- non-stick pans
- waterproof clothing

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11
Q

Define

functional group.

A

a group of atoms that are responsible for the chemical properties of a compound

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12
Q

How is

polyester formed?

A

by the condensation polymerisation of dicarboxylic acid monomers and diol monomers

these form ester links

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13
Q

What is the

functional group of carboxylic acids?

A

-COOH

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14
Q

What is the

functional group of diols?

A

-OH

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15
Q

What are some examples of

naturally occurring polymers?

(3)

A
  • DNA
  • proteins
  • starch
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16
Q

What is

DNA?

and what is it’s purpose?

A

a large molecule that takes a double helix structure

it is made of two polymer chains of four different types of monomers

17
Q

What are the

two functional groups of amino acids?

A

-COOH and -NH2

18
Q

How are

proteins formed?

A

by the condensation polymerisation of amino acids

19
Q

What are

carbohydrates?

and what are they used for?

A

molecules containing carbon, oxygen and hydrogen

used by living things to produce energy

20
Q

What is

starch?

A

a polymer made up of many smaller units of carbohydrates (nown as sugars) joined together in a long chain

21
Q

What are the environmental and economic issues with the

raw materials of plastics?

A

Plastics are made from crude oil. This is a finite resource meaning that eventually it will all get used up and run out.

The more we use the crude oil products, the more expensive crude oil will become, so price of crude oil products will also increase.
Also, as resources dry up, we will have the issue of how to use the remaining oil.

22
Q

What are the

two main disposal methods of plastics?

A
  • landfill
  • combustion
23
Q

What are the key negatives of

landfill?

A
  • lots of valuable land is quickly getting used up for use as landfill sites
  • most polymers are non-biodegradable so will sit in landfill for many years
24
Q

What are the positives and negatives of

disposal of polymers by combustion?

(1+, 1-)

A

+releases a lot of energy which can be used to generate electricity or heat homes
-toxic gases can be released from the combustion

25
Q

What are the

positives of recycling polymers?

(5)

A
  • reduces the amount of non-biodegradable waste filling up in landfill sites
  • reduces emissions of greenhouse and toxic gases which can be released from burning polymers
  • generally uses up less water and energy resources than making new plastic does
  • reduces the amount of crude oil needed to produce more plastics
  • recycling saves money and creates jobs
26
Q

What are the

negatives of recycling polymers?

(5)

A
  • polymers must be separated before they can be melted and reformed (which can be difficult expensive)
  • it can be more expensive than producing new products from raw materials
  • if polymers are mixed together, the quality of the final polymer product could be reduced
  • polymers can only be recycled a finite amount of times
  • melting down polymers can release dangerous gases into the atmosphere - these are harmful to plants and animals

GCSE Edexcel Chemistry (23 decks)

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