Unit 1b - Oils, Earth And Atmosphere Flashcards
What do long chain hydrocarbons form?
Thick gloopy liquids like tar
What is the process called that turns longer molecules produced from fractional distillation into smaller ones called?
Cracking
An example of a product from cracking being used as a fuel
Petrol for cars or paraffin for jet fuel
What other substances are produced in cracking besides fuels and what is its purpose?
Ethene. Making plastics.
What can you get when you crack disel?
Petrol, paraffin and ethene
What kind of reaction is cracking?
Thermal decomposition
How do you crack a long chain hydrocarbon?
Heat the long chain hydrocarbons to VAPORISE it then the vapour is passed over a POWDERER CATALYST (aluminium oxide) at a temperature of about 400C - 700C and the long chain molecules SPLIT APART on the surface of the specks of catalyst
What does thermal decomposition reaction mean?
Breaking molecules down by heating them up
What is the catalyst used for cracking?
Aluminium oxide
What are most of the products of cracking called?
Alkanes and Alkenes
What is an alternative way to crack the hydrocarbons?
Mix the vapour with steam at a very high temperature
What is the general word equation for cracking a long chain hydrocarbon?
Long-chain hydrocarbon molecule –> shorter alkane molecule + alkene
(Kerosene –> octane + ethene)
What is the general formula for an alkane?
CnH2n+2
What is the general formula for an alkene?
CnH2n
What does cracking mean?
Splitting up long chain hydrocarbons
What kind of bond do alkenes have?
A C=C double bond
A carbon double bond
Why are alkenes known as unsaturated?
Because they can make more bonds as the double bond can open up allowing the two carbon atoms to bond with other atoms
What are the first two alkenes?
Ethene, propene
What is the formula for ethene?
H H \ / C=C / \ H H
What is the formula for propene?
H H H | | / H-C-C=C | \ H H
What is the test for an Alkene?
Adding the substance to bromine water the Alkene will decolourise the bromine water turning it from orange to colourless.
Why does alkenes turn bromine water colourless ?
The double bond has opened up and formed bonds with the bromine
How can ethene produce ethanol ?
It can be hydrated with steam in the presence of a catalyst to make ethanol
Why is reacting ethene with steam to produce ethanol cheap!
Because ethene is fairly cheap and not much of it is wasted
What is the trouble with using ethene to produce ethanol?
Ethene is produced from crude oil which is non renewable that could start running out fairly soon so using ethene to make ethanol will become very expensive in the future
What can ethanol be produced from besides ethene?
Renewable resources by fermentation
What is the raw material used for fermentation called and how is it converted to ethanol?
Sugar and it is converted into ethanol using yeast
What is the word equation for converting sugar into ethanol?
Sugar –> carbon dioxide + ethanol
What are the advantages to producing ethanol using fermentation instead of ethene?
It requires a lower temperature, simpler equipment, renewable, used as a cheap fuel in some countries that don’t have oil reserves for making petrol
Why is sugar a good material to use to make ethanol?
It is grown as a major crop in several parts of the world including many poorer countries
What are the disadvantages to making ethanol from fermentation instead of ethene?
The ethanol produced isn’t very concentrated so if you want to increase its strength it needs to be distilled (as in whisky distilleries), and it needs to be purified
What kind of bonds do Alkanes have?
single carbon bonds
What was used before polythene bags?
String bags
What can alkenes be used to make?
Polymers
What is it called when you join together lots of small alkene molecules to form large molecules?
Polymerisation
What is polymerisation?
Joining together lots of small alkene molecules to form large molecules and these long chain molecules are called polymers
What are small alkene molecules known as?
Monomers
What can may ethene molecules be joined up to form?
Poly(ethene) or polythene
What does a polymers structure look like?
H H H H H H | | | | | | -C-C-C-C-C-C- | | | | | | H H H H H H
What is the general name for a polymer?
Poly(whatever the alkene was)
What do you use for polymerisation?
Pressure and a catalyst
What do the physical properties of a polymer depend on?
What it’s made from
What is an example of something stronger than poly(ethene)
Polyamides
What are a polymers physical properties affected by?
Temperature and pressure of polymerisation
What is characteristics of poly(ethene) made at 200*c and 2000 atmospheres pressure
Flexible with a low density
What are the characteristics of poly(ethene) made at 60*c and a few atmospheres pressure with a catalyst
Rigid and dense
What are light, stretchable polymers that are used to make plastic bags called?
Low density poly(ethene)
What are elastic polymer fibres used to make?
Super stretchy Lycra fibre for tights
What are some uses of polymers
Water proof coating force rocks, dental polymers are used in resin tooth filing, polymer hydrogel wound dressings keep wounds moist
What are the new biodegradable packaging materials that are being produced made from?
Polymers and cornstarch
What is an example of a smart material and what is a smart material?
Memory foam And a polymer that gets softer as it gets warmer and mattresses can be made of memory foam
Why are most polymers not biodegradable?
They are unable to be broken down by microorganism so they don’t rots and it’s difficult to get rid of them
What is the best thing to do with polymers that aren’t biodegradable?
Re-use them as many times as possible and recycle then otherwise so they’d be in a land fill site for years
What are things made from polymers in comparison to those made of metal?
Cheaper
Why will the price of crude oil rise and what impact will this have on polymers?
Because crude oil resources get used up so the price of crude oil will rise so will the polymers and one day there el t been ought oil for every use so polymers made using crude oil may not be made
What is an example of naturally occurring polymers?
Rubber and silk