C1 Alkenes, Cracking and Polymers

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what is cracking
splitting up long chain hydrocarbons by passing vapour over a hot catalyst
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3 products made from cracking
petrol, paraffin, ethene for plastics
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what type of reaction is cracking
thermal decomposition
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first step to cracking
heat the long chain hydrocarbon to vaporise it
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second step to cracking
pass the vapour over a powdered catalyst
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what is the temperature range used
400-700 degrees Celsius
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what is the catalyst used
aluminium oxide
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what happens on the surface of the catalyst
the long chain molecules split apart (crack) on the surface of the specks of catalyst
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what are the products of cracking
alkanes and unsaturated hydrocarbons (alkenes)
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what is created in the cracking of kerosene
octane and ethene
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what is ethene
two C atoms, is for making plastics
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what do alkenes have
C=C double bond (carbon double bond)
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what are alkenes known as + why
unsaturated because they can make more bonds
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how do they make more bonds
the double bond can open up, allowing the two carbon atoms to bond with other carbon atoms
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what are first two alkenes
ethene, propene
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what is the general formula for an alkene
CnH2n
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what is the test for alkenes
adding the substance to bromine water, if alkene is present the browmine water will go from orange to COLOURLESS
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why does the colour change
the double bond has opened up and formed bonds with the bromine
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what does ethene + water make
ethanol
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what state must the water be in
steam, vaporised
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what is this process called
fermentation
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what does there need to be for this process to occur
catalyst
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what is the process like
cheap
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why will this change
ethene is made from crude oil which is a non renewable resource so making ethanol could become expensive
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another way to produce ethanol
fermentation of sugar
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2 differences of this process than with the fermentation of ethene
lower temperature needed and need simpler equipment
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a pro for the raw material sugar being used instead of ethene
sugar is renewable
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why is this a pro for countries which are poor with no oil reserves
they can grow the sugar
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2 cons to fermentation of sugar
ethanol produced has a low concentration and needs to be purified
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how are the majority of alkenes used
to make polymers
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what is the process called
polymerisation
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what happens in this process
joining together lots of monomers to form polymers
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whats a monomer
small alkene molecule
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whats a polymer
long chain molecules
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what is needed in the polymerisation process
pressure and a catalyst
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how do you name the polymer made
add poly, example: polyethene, polypropene
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what affects the properties of the polymer
what its made from, temperature and pressure of polymerisation
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how do properties affect the use
makes them suitable for various different uses
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disadvantage to plastics
not biodegradable so dont rot
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how do we resolve this
re-use and recycle them as much as possible
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comparison of price between plastics and metals
plastics are cheaper
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why might this change
as crude oil resources get used up the price of crude oil will rise
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Other cards in this set

Card 2

Front

3 products made from cracking

Back

petrol, paraffin, ethene for plastics

Card 3

Front

what type of reaction is cracking

Back

Preview of the front of card 3

Card 4

Front

first step to cracking

Back

Preview of the front of card 4

Card 5

Front

second step to cracking

Back

Preview of the front of card 5
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