Topic 6A,B,C - Alkanes and Alkenes (Organic Chemistry) Flashcards
What is a Homologous series?
A series of compounds containing the same functional group so have same general formula and chemical properties
What is a Functional Group?
A single atom or group of atoms that gives a compound its chemical properties
Definition of Molecular formula
The formula which shows the actual number of each type of atom
Definition of a empirical formula
Show the simplest whole number ratio of atoms of each element in the compound
Definition of Structural formula
Shows how atoms are grouped together in a molecule
Definition of Displayed formula
Shows all the atoms and all the bonds in a molecule
Definition of Skeletal formula
Shows a simplified structural formula only show carbon -carbon bonds (as lines) and functional groups of present
What are 3 properties of a homologous series
- They show a gradual change in physical properties e.g boiling point
- Each member differs by CH2 (the same difference) from the last
- They have the same chemical properties
What are the general rules for naming carbon chains?
- Count the longest carbon chain and name appropriately, find any branched chains and figure out the carbon they are coming off and the functional group that they are e.g 3,5 - dimethylheptane meaning that the longest carbon chain is 7 and there are 2 methyl groups coming off the 3rd and 5th carbon
- You have to make sure that the numbers are the smallest possible
- When naming with multiple functional groups the order of them is alphabetical
- Words are separated by numbers with dashes and numbers are separated by commas
- When writing the structural formula of molecules that have functional groups e.g methyl coming off of them you need to put brackets around it e.g CH3CH(CH3)CH3
Definition of an Isomer/ structural isomer
Molecules with the same molecular formula but a different structural formula
What are the 2 types of isomers?
- structural isomers
- stereoisomers
What are the 3 types of structural isomers?
- Chain isomers
- position isomers
- Functional group isomers
What is the definition of a chain isomer?
Compounds with the same molecular formula but different shaped/ structured chains e.g straight chain or branched e.g pent-1-ene and 3-methylbut-1-ene
What is the definition of a position isomer?
Compounds with the same molecular formula but different structures due to different positions of the functional group on the molecules e.g pent-1-ene and pent-2-ene
What is the definition of a functional group isomer?
Compounds with the same molecular formula but with the atoms arranged to give different functional groups e.g Alkenes and Cyclo Alkanes have the same molecular formula but different functional groups
What is the definition of a stereoisomer?
Molecules with the same molecular and structural formula but with a different arrangement of atoms in space e.g cis/trans isomers and E/Z isomers
What are the 5 types of reactions?
Addition, Polymerisation, Elimination, Substitution, Hydrolysis.
When do addition reactions occur?
When molecules contain a double bond e.g In Alkenes, they are said to be unsaturated and the carbon-carbon double bond can break and gain another molecule in an addition reaction.
When do polymerisation reactions occur and give an example?
Addition polymerisation occurs when small molecules (monomers) with double bonds e.g Alkenes, add to each other and join up in long chains to form polymers. The reaction
needs a suitable catalyst and temperature. An example; n(C2H4) -> -(C2H4)-n
When do elimination reactions occur and give an example?
An elimination reaction is basically the opposite of an addition reaction, it splits off a simple molecule e.g water or hydrogen chloride, from a larger molecule leaving a double bond e.g C2H5Cl -> C2H4 + HCl (in the presence of NaOH, ethanol and heat)
When do substitution reactions occur and give an example?
Substitution reactions occur when an atom or group of atoms is replaced by another atom or group of atoms e.g alkanes + halogens (in the presence of UV light) -> halogenoalkanes + Hydrogen halides
When do hydrolysis reactions occur and give an example?
Hydrolysis is used to describe any reaction in which water is used to split apart a molecule (don’t need to know the process in detail). To recognise this reaction you would see water as a reactant and the reaction is often catalysed by an alkali or acid. Hydrolysis reactions are often substitution reactions in which the chemical attack is by nucleophiles such as water molecules or hydroxide ions.
What are nucleophiles?
Nucleophiles are molecules or ions that have a lone pair of electrons that is able to form a new covalent bond. For example; Oxygen in hydrogen oxide, Carbon in carbon nitride, Oxygen in water, Nitrogen in Ammonia
- They are electron pair donors
- They attack ions/molecules with a partially positive charge
What are electrophiles?
An electrophile is a species which can accept a pair of electrons from an electron rich sire in another molecule to form a new covalent bond. Electrophiles are often positively charged e.g H+
- They are ‘electron loving’ reagents
- Electrophiles form a new bond by accepting a pair of electrons from the molecule or ion attached in the reaction
What is a polymer?
Polymers are large chains formed from huge numbers of small molecules (repeat units) called monomers
What type of addition do alkenes undergo?
Electrophilic addition - The electrophiles (the positive ions with a vacant orbital) attack the negatively charged region of the C=C bond
What is the definition of addition polymerisation?
The joining together of small molecules that contain a carbon-carbon double bond to form a long chain
What are two safety hazards when cracking and what is the solution to them?
- One hazard is that the gas you are producing and paraffin is flammable so therefore you have to make sure the gas is being collected over water
- One hazard is that the glassware can get very hot as it is being heated so before you move touch it ensure it has cooled down
What is the shape of a saturated hydrocarbon?
Tetrahedral with a bond angle of 109.5°
What is homolytic fission?
This is when each atom of a molecule gets one electron from the covalent bond, the electrons are shared equally.
What are cycloalkanes?
These molecules contain a ring of carbon atoms and have the general formula CnH2n (same as alkenes)
How would you draw 2,2 -dimethylheptane
7carbon atoms making up the main chain and then on the second carbon atom their would be two methyl groups coming off it.
What type of bonds do alkanes contain?
Single covalent bonds known as sigma bonds
What is the bond axis?
The bond axis is the invisible line between the nuclei of the atoms being bonded together
When will sigma bonds form?
When their is head on overlap of orbitals along the bond axis
What are the 3 ways sigma bonds can form?
- The overlap of 2 sigma bonds
- The overlap of a sigma bond and a head on pi bond
- The head on overlap of 2 pi bonds
Are alkanes reactive? Why?
No, as the C-C and C-H bonds have high bond energy values which require a lot of energy to overcome
Are alkanes likely to be polar molecules? Why?
No, as there are no polar bonds between the carbon and hydrogen as the difference in electronegativities is negligible
What are 2 qualities about the carbon-carbon bond in alkanes?
- It is symmetrical
- There is free rotation about the single bond
Alkane + Halogen →…
NO REACTION
What is the reaction of a Halogen with an organic compound used to test for?
Whether the compound is an alkene or alkane
What is the colour change of Bromine Water if an alkene functional group is present?
Orange→ colourless
What are the conditions need in order for the substitution reaction of; Alkane + Halogen → Halogenoalkane + Hydrogen Halide
- UV radiation (sunlight) or above 300°C
What is the definition of a substitution reaction?
Where an atom or group of atoms is replaced with a different atom or group of atoms, 2 reactants → 2 products
What is Halogenation?
Where an alkane and a halogen (chlorine or bromine) react in the presence of UV radiation (sunlight)
What type of reaction is halogenation?
Free radical substitution (also a photochemical reaction)
What are the 3 stages of a Halogenation reaction?
Initiation
Propagation
Termination
What does a half arrow indicate when drawing a mechanism?
Movement of a single electron
What does a full arrow indicate when drawing a mechanism?
Movement of a pair of electrons
What happens in the Initiation step of Halogenation?
The UV light breaks down a chlorine/bromine molecule into uncharged halogen atoms, each with an unpaired electron show as a * (*=dot)
What is heterolytic fission?
This means that the electrons are split unequally between the atoms in the molecule and one atom gains a lone pair of electrons.
What are Free radicals?
Atoms that are uncharged and have 1 unpaired electron
Write the mechanism for the initiation step of the reaction; CH4 + Cl2 → CH3Cl + HCl
(You don’t need to know the mechanism)
Cl-Cl → Cl+Cl
Half arrows would be drawn from the bond to each Chlorine atom to show the movement of electrons
How many parts are there to the Propagation step of Halogenation?
2
For a reaction to occur what must happen?
Particles must collide with each other
Write the equation for the first part of the Propagation step of the reaction; CH4 + Cl2 → CH3Cl + HCl
CH4 + Cl* → C*H3 + HCl
From the C-H bond, 1 electron goes to the Carbon atom and 1 to the Hydrogen atom. The electron from the Chlorine free radical joins with the Hydrogen free radical.
Remember to draw the radical on the carbon atom
Write the equation for the second part of the Propagation step of the reaction; CH4 + Cl2 → CH3Cl + HCl
CH3 + Cl2 → CH3Cl + Cl
A different Cl2 molecule that has already been split in the first step donates one of its electrons to form a covalent bond with the carbon atom and its electron
What does the Propagation step continually do in the reaction; CH4 + Cl2 → CH3Cl + HCl?
Produce methyl and chlorine free radicals in a chain reaction
When does the chain reaction of a Halogenation reaction stop?
When all the free radicals eventually collide with each other
What are all the possible reactions for the final Termination step of the reaction; CH4 + Cl2 → CH3Cl + HCl?
Cl* + Cl* → Cl2
CH3 + Cl → CH3Cl
CH3 + CH3 → CH3CH3
Why does the reaction; CH4 + Cl2 → CH3Cl + HCl, have a low yield of product?
This is because the Cl* is so reactive and so therefore their are further free radical reactions of the radical with the desired product, which produces unwanted products.
Explain how crude oil is split into fractions via fractional distillation?
The crude oil is vaporised into a gas and enters the fractionating column which has a temperature gradient, hottest at the bottom and cooling as you go up. The long chain hydrocarbons with the highest boiling points will condense first, ant the bottom, and exit the column. The shorter chain hydrocarbons with the lowest boiling points will condense at the top.
What are the crude oil fractions from shortest chain length to longest?
Refinery Gas
Gasoline/Petrol
Naphtha
Kerosine
Diesel Oil
Lubricating oil
Fuel oil
Bitumen
Why do different alkanes have different boiling points?
Longer chain alkanes contain more electrons, therefore stronger London Forces which require more energy to overcome.
What are the two ways fractions are processed into more useful alkanes and alkenes?
Cracking
Reforming
What is the definition of reforming?
Turning straight chained alkanes into branched or cyclic alkanes, which are more efficient fuels as they combust easier
Why are cyclic or branched alkanes more useful?
They combust more easily so are more efficient fuels
What is the definition of cracking?
The breaking down of saturated hydrocarbon molecules into smaller hydrocarbon molecules by heat
Why is cracking an important process?
The process breaks down longer chain alkanes into shorter chain alkanes and alkenes that are in higher demand and are much more useful for the production of polymers for plastics
What are the two different conditions that are needed for cracking?
High temperatures
An aluminium oxide catalyst with low temperatures (catalytic cracking)
Describe the set up for catalytic cracking
On the right;
- a water bath
- downturned test tube that collects the gaseous product
- a Bunsen valve around the neck of the small tube that connects the test tube in the water bath and the test tube where the reaction is taking place
On the left;
- a sideways test tube
- aluminium oxide granules in the centre of the test tube
- a bung on the test tube
- Heat applied to the aluminium oxide
- ceramic fibre soaked in paraffin at the bottom of the test tube
What do fuels do when burnt?
Release heat energy
When does complete combustion occur?
In an excess/ plentiful supply of oxygen
What are the products of complete combustion?
Carbon dioxide + Water
When does incomplete combustion occur?
When there is a limited supply of oxygen
What are the products of incomplete combustion?
Water + CO/C (soot)
Why is carbon monoxide dangerous?
Carbon monoxide binds irreversibly to haemoglobin in the blood, meaning that there is less supply of oxygen to organs
What is the impact of soot in the environment?
Soot particulates can travel up into the atmosphere and reflect the suns light, contributing to global dimming
How are oxides of sulphur formed? What do they cause?
Some hydrocarbon fractions contain sulphur impurities. When these fractions are burnt the reaction S + O2 → SO2 takes place. The sulphur dioxide will rise up into the atmosphere and dissolve in the atmospheric water to form acid rain.
How are oxides of nitrogen formed? What do they cause?
Inside car engines the temperature is very high. This means nitrogen in the air and oxygen are able to react;
N2 + O2 → 2NO
N2 + 2O2 → 2NO2
NO is toxic and forms smog
NO2 is toxic and can also rise up into the clouds and dissolve in atmospheric water to form acid rain
What do catalytic converters do?
They remove; CO, nitrogen oxides and unturned hydrocarbons from the exhaust gases of cars, turning them into less harmful; CO2, N2 gas and water
An example equation of a catalytic converter is; 2CO + 2NO → …
2CO2 + N2
What is the structure of catalytic converters? Why?
They have a honeycomb structure which gives them a large surface area
What are the catalyst metals used in catalytic converters?
Platinum, palladium, rhodium
What are 2 examples of renewable, plant based fuels?
Alcohols and Biodiesel
What is a natural way that ethanol can be produced?
Via the fermentation of glucose from plants
Write a symbol equation showing the fermentation of glucose
C6H12O2 → 2C2H6O + CO2
What is used to catalyse the fermentation of glucose?
- yeast
- anaerobic conditions
How is biodiesel produced?
Reacting vegetable oils with a mixture of alkali and methanol
Why is the use of biofuels described as being carbon neutral?
When the biofuels are burnt, the CO2 that was taken up during photosynthesis when the plants were growing is released back into the air
What are 3 advantages of using biofuels?
- Renewable and sustainable energy source
- More carbon neutral
- Using Biofuels means using up less fossil fuels so there are more for making other organic compounds
What are 3 disadvantages of using biofuels?
- Production of them can be inefficient
- They use chemical pesticides and fertilisers in order to grow the plants
- less space from planting food crops
- shortage of fertile soil
What property allows crude oil to be separated by fractional distillation?
It is a mixture of hydrocarbons with different boiling points
Why does the process of cracking require high temperatures?
In order to break the bonds between carbons
Why are alkenes more reactive than alkanes?
In alkenes the pi bond will break easily as the pi electrons lie exposed above and below the rest of the molecule, so they are less controlled by the carbon nuclei, therefore they are relatively open to attack by other things. Alkanes only contain this sigma bond which is less likely to be attacked and broken.
Why are alkenes referred to as unsaturated hydrocarbons?
As they contain a carbon-carbon double bond
When naming the organic compound, what must the longest carbon chain contain in alkenes?
The C=C bond
How is the chain numbered in alkenes?
To show the position of the double bond, giving it the lowest number possible
Draw the display formula of but-2-ene
- Double bond between the 2nd and 3rd carbon
Draw the display formula of pent - 1,3 - diene
- Double bonds between the 1st - 2nd, 3rd - 4th carbon
Draw the display formula of cyclohexa - 1,3 - diene
The display formula of cyclohexane but with 2 double bonds that are one space apart (you label the carbons the numbers that you want as it doesn’t make a difference)
What does the shape of a molecular orbital show?
The regions of space within the molecule where there is a high probability of finding a particular pair of electrons
What does atomic orbitals overlapping result in?
Bonding between atoms
When do molecular orbitals form?
When atomic orbitals overlap
What is a sigma bond?
A single covalent bond formed by a pair of electrons in an orbital in a molecule
Where is the electron density found in a sigma bond?
Between the 2 nuclei
Where are pi bonds found?
In double and triple bonds
How is a pi bond formed?
The sideways overlap of 2 p orbitals
Where is the electron density found in a pi bond?
The electron density in a pi bond is concentrated in 2 regions, one above and one below the plane of the molecule
Why is rotation around a pi bond restricted?
As if there was any rotation the p-orbitals would no longer overlap sideways
How do you draw electron density in a carbon double bond?
- A circle between the nuclei due to the sigma bond
- 2 circles, above and below the sigma electron density, due to the pi bond
What is the shape and bond angle of alkene molecules around the C=C bond?
- Planar shape
- 120° between the Hydrogen and Carbon atom
When an alkene reacts which bond breaks and why?
The pi bond as it has a lower bond energy than a sigma bond so it is energetically more favourable to have 2 molecules with sigma single bonds.
Draw and name the structural isomers with the molecular formula C4H8
but-1-ene, but-2-ene, 2-methylpropene
What two factors are required for geometric isomers to form/be possible?
- Presence of a C=C bond
- Each Carbon in the double bond must have a different atom or group bonded to it
Why does a geometric isomer require a C=C bond?
In a C=C bond the carbon atoms cannot rotate about the bond
When does a geometric isomer have the prefix cis?
When the same group, on the different carbon atoms, are on the same side
When does a geometric isomer have the prefix trans?
When the same group, on the different carbon atoms, are on different sides
Draw the cis and trans isomers of C4H8
1 - Has 2 hydrogen groups on the same side
2 -Has 2 hydrogen groups on opposite sides
When can you not have a geometric isomer?
When you have 2 of the same functional groups/ groups of atoms coming off the same carbon
Why is it not always possible to use cis/trans naming when naming geometric isomers?
As cis/trans requires one group on the different carbon atoms to be the same, if the groups are all different you cannot use this naming method
When do we use E/Z naming?
When no 2 groups are common/the same around a double bond
What is the priority group?
The atom, or group of atoms, which the highest atomic number on each of the carbons. When these are on the same side it is a Z stereoisomer and when these are on opposite sides it’s is an E isomer
What do E and Z mean/stand for?
E - entgegen, opposite
Z - zusammen, the same
Which bond is weaker, pi or sigma?
Pi bond
What is the reagent in the bromination of Ethene?
Bromine (In general the halogen)
What are the conditions required for the bromination of Ethene?
Room Temperature
What type of reaction is the bromination of ethene?
Electrophilic addition, where the electrophile Br (partially +) is attracted to the negatively charged region of the C=C bond
How does the Br2 molecule that is non-polar gain a partially positive and negative charge in the bromination of Ethene?
As the Br2 molecule approaches the high electron density pi bond, the electrons within the Br2 molecule are repelled from one end giving that end a delta + charge (an induced dipole)
What type of bond breaking takes place In the bromination of Ethene? In what bond?
Heterolytic Fission occurs in the Br-Br bond
What happens when the Br2 bond breaks heterolytically?
- The Br atom gaining the electrons gains a lone pair of electrons and an overall negative charge
- The Br atom that has a partially positive charge and is being attracted to the pi bond, forms a new C-Br bond
Write the equation for the reaction between ethene and bromine
C2H4 + Br2 → CH2BrCH2Br
What is the C2H4Br molecule?
A carbocation, as there is a positive charge on the carbon
In the bromination of Ethene what does the carbocation attract to form?
The carbocation attracts the Br- ion to form another C-Br bond and the molecule 1,2-dibromoethane
Draw out the reaction mechanism for the bromination of Ethene?
1st Step
- Br2 has a dipole, partially positive closer to the double bond and the other side negative
- An arrow is drawn from the C=C bond to the Br (delta +) atom
- An arrow is drawn from the Br-Br bond to the Br (delta -)
2nd Step
- The Br- ion has a lone pair of electrons
- The Carbocation has a positive charge on a carbon that was in the double bond
- An arrow is drawn from the lone pair of electrons to the carbon with a positive charge
This forms a dihaloalkane
Write the equation for the reaction of Alkenes (ethene) and Bromine Water
C2H4 + H2O + Br2 → CH2BrCH2OH + HBr
What does H2O dissociate into?
OH- and H+ (this reaction is reversible and constantly happening)
What is the major product of the reaction of Ethene with bromine water? Why?
2-bromoethanol. This is because OH- ions take part in the reaction and ,since they are a stronger Nucleophile than Br- ions, they bond with the carbon atom with a + charge
Draw out the reaction of Ethene with Bromine water
1st Step
- Br2 has a dipole, partially positive closer to the double bond and the other side negative
- An arrow is drawn from the C=C bond to the Br (delta +) atom
- An arrow is drawn from the Br-Br bond to the Br (delta -)
2nd Step
- There is a Br- ion, however this does not take part in the reaction
- There is an OH- ion with a lone pair of electrons, acting as the nucleophile
- The carbocation has a positive charge on one of the carbons that was involved in the carbon-carbon double bond
- An arrow is drawn from the lone pair of electrons on the OH- ion to the Carbon+ ion
This forms a haloalcohol
Why do alkenes undergo electrophilic reactions?
As alkenes contain a double bond, which forms a region of high electron density, that is negatively charged. This strongly attracts electrophiles, species that want to gain electrons.
Write the equation for the reaction of an alkene (ethene) with a hydrogen Halide (hydrogen bromide)
C2H4 + HBr → CH3CH2Br
What is the reagent and the conditions in the reaction of C2H4 and HBr?
Reagant - HCl or HBr gas
Conditions- Room Temperature
Why does the H atom act as the electrophile in H-Br?
The molecule is polarised as Br has a higher electronegativity. This gives H a partially positive charge which therefore attracts the electrons in the C=C bond
Draw out the mechanism of the reaction of Ethene with hydrogen bromide
1st Step
- The H-Br molecule has a partially positive charge on the H atom and partially negative charge on the Br atom (the molecule is already polarised)
- An arrow is drawn from the C=C bond to the H atom
- An arrow is drawn from the H-Br bond to the Br atom
2nd Step
- The Br- ion has a lone pair of electrons
- The Carbocation has a positive charge on a carbon that was in the double bond
- An arrow is drawn from the lone pair of electrons to the carbon with a positive charge
This forms a Halogenoalkane
Which reaction with an alkene produces a major and minor product?
Alkene + Hydrogen Halide
Why does propene produce a major and minor product but not ethene or but-2-ene?
Ethene and but-2-ene are symmetrical molecules so you will produce the same product. Propene is not symmetrical so therefore 2 different products can be formed from its reaction
Draw the 2 possible products of the reaction of propene + HBr
- 2-bromopropane (bromine on the second C atom)
- 1-bromopropane (bromine on the first C atom)
What is the major product of the reaction of propene + HBr?Why?
2-bromopropane is the major product. This is because it goes via a secondary carbocation which is more stable that a primary carbocation, which 1-bromopropane is produced by, as it has electrons donated by 2 alkyl groups rather than just one.
What is the difference between a primary and secondary carbocation?
The positively charged carbon is surrounded by 2 alkyl groups in a secondary carbocation in comparison to only 1 alkyl group in a primary carbocation
What is the definition of the inductive effect?
The tendency of atoms or groups of atoms to push electrons (or pull electrons towards a carbon atom)
Why is a major product more likely to form via a secondary carbocation intermediate?
A secondary carbocation is more stable, due to more alkyl groups stabilising the positive charge with electrons, therefore the major product is more likely to form
Alkyl groups are electron…
Donating
Explain, by referring to the mechanism, why the major product is formed in the reaction of C3H6 + HBr → CH3CHBrCH3
2-bromobutane is the major product as it is formed via the secondary carbocation. This means it is more stable than the primary carbocation which the 1-bromobutane forms via, as the bromine is bonded to a carbon which is bonded to 2 alkyl groups, not just one
When do alkenes react with potassium manganate?
The cold
Write the equation for the reaction of Ethene with the oxidising agent potassium manganate (VII) solution
C2H4 + H2O +[O] → CH2OHCH2OH (a diol)
What are the reagents and conditions for the reaction of Alkene with Potassium Manganate?
Conditions - Cold
Reagant - KMnO4 (potassium manganate VII) acidified with sulfuric acid
What is the test for the alkene functional group?
Add KMnO4 (Potassium Manganate VII) solution
What is the colour change for the test for alkenes?
Purple → colourless
(In alkali conditions a brown precipitate may form )
What are the conditions required for ethene to react with H2 gas?
- Nickel catalyst
- High Pressure (20atm)
Write the equation for the reaction of Ethene with Hydrogen gas
CH2CH2 + H2 → (Ni) CH3CH3
What is the reaction of Ethene + Hydrogen gas used to prepare?
- Alkanes
- It saturates the double bonds in natural oils to make them into solids, for example manufacturing margarine from vegetable oils
What are the conditions need for alkenes to react with steam?
- Phosphoric acid catalyst
- 60-70 atm
- 300°C
What functional group is produced from the reaction of alkenes with steam?
Alcohols, OH
What is the reagent in the reaction of alkene and steam?
Steam
Write a balanced polymer equation for the monomer but-1-ene (you can also be asked to draw the monomer from the polymer given)
n (display formula of but-1-ene) → [CH2CH(CH3)] polybut-1-ene
Note: the polymer display formula has a singe C-C bond not a double and has arms that extend through the brackets
What are the conditions required for polymerisation reactions?
- High pressure
- Suitable catalyst
What are the 4 main methods of disposal of alkenes/organic compounds?
- Recycling
- Incineration
- Landfill
- Feedstock for cracking
What are some pro’s of recycling?
- Reduces the waste to landfills
What are some cons of recycling?
- Slow process
- Costly
- Difficult
What are some pro’s of incineration?
- Produces energy that can by used to heat
What are some cons of incineration?
- Increases greenhouse gas emissions and therefore the enhanced greenhouse effect
- Could release toxic gases
What are some pro’s of a landfill?
- Cheap
- Easy
-Quick
What are some cons of a landfill?
- Takes up space
- Visual pollution
What are some pro’s of Feedstock for cracking?
- Prevents excess use of crude oil
What are some cons of Feedstock for cracking?
- decomposition produces methane as a greenhouse gas
What is the definition of biodegradable?
The ability of a material to decompose by bacteria or other living organisms
What are 2 examples of a biodegradable polymer?
- Cellulose
- Polypeptides
What are 2 major uses of the polymer polythene?
- Plastic; bags, bottles and beakers
- Insulation for cables
What are 2 major uses of the polymer Polypropene?
- Fibre for ropes and carpet
- Toys
What are 2 major uses of the polymer PVC?
- Guttering and window frames
- Waterproof; clothing, flooring and clingfilm
What are 2 properties of the polymer polythene?
- Light
- Flexible
- Easily molded
- Transparent
What are 2 properties of the polymer Polypropene?
- Tough
- Easily molded and coloured
What are 2 properties of the polymer PVC?
- Tough
- Very resistant to water, acids and alkalis
