Production of Materials Flashcards
1
Q
what is the most important hydrocarbon used in the petrochemical industry?
A
ethene or ethylene
2
Q
what is the chemical formula for ethylene?
A
C2H4
3
Q
what are some properties of ethylene?
A
- alkene (unsaturated)
- low MP and BP
- Insoluble in water
- carbon double bond is a region of high electron density
4
Q
where does ethylene usually come from?
A
via cracking large hydrocarbons sourced from fractionally distilling crude oil
5
Q
what is cracking ?
A
cracking is the process in which large, long chain hydrocarbons are broken up into smaller and more useful hydrocarbons
6
Q
why would some hydrocarbons get cracked?
A
most large hydrocarbons are in low demand, unlike short chain hydrocarbons, thus for profit these large hydrocarbons are cracked to form smaller more profitable hydrocarbons
7
Q
why is ethylene so special?
A
because it holds unlimited potential on in the petrochemical (plastics) industry due to its versatility and the variety of reactions and compounds it can undertake in and make respectively
8
Q
what are the three forms of cracking ?
A
steam cracking
thermal cracking
catalytic cracking
9
Q
what does catalytic cracking entail?
A
catalytic cracking ulitises a zeolite catalyst to lower the temp required to extract these useful components when cracking
10
Q
what are the properties of the zeolite catalyst used in catalytic cracking?
A
- high surface area
- Porous
- selective
11
Q
what are the conditions required for catalytic cracking ?
A
- atmospheric pressure
- absense of air
- temps at approx 500 degrees celcius
12
Q
what is the difference between a saturated and unsaturated hydrocarbon ?
A
saturated
contains only single bonds, and no more atoms can be added to it
unsaturated
contain double or even triple bonds, allowing additional parts to join the chain
13
Q
why are alkenes much more reactive than alkanes?
A
an alkenes double bond makes it inherently more unstable as it is a region of high electron density and thus can break apart more readily than an alkanes single bonds
14
Q
why is ethylene so reactive?
A
because of its double bond and how it is a region of high electron density with the ability to attract electronegative species such as halogens and thus create many other different compounds as a result
15
Q
what are the four main types of addition reactions which ethylene commonly participates in?
A
hydrogenation- heated with hydrogen with a catalyst
halogenation- halogens react with ethylene with no catalyst
hydrohalonation- hydrohalogen such as HCl react with no catalyst
Hydration- production of ethanol where ethylene reacts with water in dilute sulfuric acid
16
Q
what is a monomer?
A
the simplest molecule from which a polymer is made through polymerisation
17
Q
what are the common polymers made from ethylene?
A
polyethylene
polystyrene
polyvinylchloride
polyproplyene
18
Q
how can something like polyethylene be made from ethylene?
A
numerous ethylene molecules join together through the breakage of their double bonds, forming a long chain of repeating monomer units
19
Q
what type of polymer is polyethylene?
A
an addition polymer
20
Q
what is an addition polymer?
A
an addition polymer is a polymer made from the joining of individual monomers without the loss of any atoms. in some ways it can be thought of as the reverse of cracking, where long chain saturated hydrocarbons are formed through joining countless unstaturated hydrocarbons together
21
Q
what are the two types of polyethylene?
A
HDPE and LDPE
high and low density polyethylene
22
Q
what are the conditions like underwhich LDPE is made?
A
- temp range of 80-300 degrees celcius
- very high pressures (3000 atms)
23
Q
what are the three steps in the production of LDPE
A
Initiation
Propagation
Termination
24
Q
what occurs in the initiation stage for LDPE?
A
- oxygen or organic peroxide initiates the rxn
- produces ethylene free radicals which are denoted by R.
25
what occurs in the propagation stage for LDPE?
-chain grows via the joining of more monomer units
26
what occurs in the termination stage for LDPE?
-chain growth eventually stops, comes into contact with another free radical
27
what are the properties of LDPE?
- extensive branching and is widely spaced apart
- weak dispersion forces present due to wideness
- low MP and BP
- extensive branching is a cause for its low density
28
what are some uses of LDPE?
disposable plastic bags
plastic trays
cling wrap
plastic takeaway boxes
29
why is it important to seek alternative sources of compounds presently obtained from the petrochemical industry?
- petrochemicals are non renewable; as societies become more industralised the need for petrochemicals will become so great that every source runs out completely
- current production trends for petrochemicals are unsustainable
- current sourced petrochemicals are non biodegrabale, and thus build up and lead to major disposal problems and mass strain on landfills
- current petrol products burn uncleanly, releasing harmful pollutants into the atmosphere such as carbon dioxide and sulfur dioxide. contributes to the greenhouse effect and acid rain.
30
what is a condensation polymer?
a polymer chain formed by the joining of monomer units whcih detach and condense out small molecules, unlocking the monomers to be attached.
usually this released molecule is water
31
what is cellulose?
cellulose is a condensation polymer made from glucose monomers. it is a major component of plant cell walls and a major component of biomass
32
what is biomass?
biological material derived from livng or recently living organisms
33
what are some advantages in using cellulose as a raw material to build petrochemicals?
- its abundant and readily available from plant waste material
- its renewable and reduces the greenhouse effect when grown
- more biodegrable than petrochemical plastics, and so can be broken down much easier and thus wont take up much space
34
what are the disadvantages in using cellulose as a raw material to build petrochemicals?
- good for short terms plastics but not long terms once due to its biodegradability
- immense amount of energy required to convert cellulose into glucose; not ecomonmically viable, also becomes non environmentally friendly as fuels are burned and used up to extract them anyway
35
how do i turn ethene into ethanol?
react it with water in the addition reaction in conjunction with dilute sulfuric acid as a catalyst
36
how do i turn ethanol into ethylene?
place the ethanol into a concentrated solution of hydrogen sulphate, and warla
37
what is a galvanic cell?
a galvanic cell is a device which converts chemical energy into electrical energy
38
what does a galvanic cell consist of?
a galvanic cell consists of:
- two electrodes, one anode and one cathode
- two electrolyte solutions
- one salt bridge
- two containers or beakers
39
what does a salt bridge do in a galvanic cell?
a salt bridge allows the migration of ions to maintain a balance of negative and positive charges in each half cell.
anions migrate to the anode and cations migrate to the cathode
40
what is the salt bridge(what is it made of)?
usually an ionic substance like potassium nitrate
41
what happens at the anode in a galvanic cell?
there is a loss of electrons at the anode, through which it is called the reductant. the more reactive substance is the one which loses electrons
42
what happens at the cathode in a galvanic cell?
the electrons lossed at the anode migrate to the cathode of which there is a gain of electrons. the cathode is called the oxidant. the less reactive substance is the one which gains electrons
43
what is a redox reaction?
a redox reaction involves the loss and gaining of electrons. reduction and oxidation reactions
44
OILRIG?
Oxidation is Loss, Reduction is Gain(of electrons)
45
AnOX RedCAT?
oxidation occurs at the anode, and reduction happens at the cathode.
46
what is an electrode?
a conductive material that is connected to the external circuit in a galvanic cell
47
what is an electrolyte?
a substance, either a solution or a solid in a molten state, which accomodates the flow of electrons and hence conducts electricity.
48
what is an isotope?
an isotope is an element that has the same number of protons but a different number of neutrons.
49
what are the conditions required for an element to be radioactive?
an element with an atomic number <20 must:
not have a proton:neutron ratio of 1:1
an element with an atomic number 20
50
what are the three types of radiation?
alpha, beta and gamma radiation
51
what is alpha radiation and what is its charge?
positively charged helium nucleus with +2 charge
52
what is beta radiation and what is its charge?
negatively charged electron with -1 charge
53
what is gamma radiation what is its charge?
high energy photon with no charge (0)
54
what is a gieger muller counter and how does it work?
a device which detects ionsining radiation.
its consists of a tube with a mica window, electrical circuit and electrodes (the casing and fine wire).
1. Radiation, either alpha, beta or gamma enters the window and ionises the gas inside the tube(argon, neon or methane gas at low pressure).
2. This causes molecules to ionise and lose electrons, causing even more molecules to shed electrons.
3. These electrons then move to the outer casing (cathode), forming an electrical impulse which is amplified and produces clicks.
55
What is photographic film and how does it work?
film which contains silver halide crystals
when exposed to radiation a reaction occurs involving the silver halide crystals causing the film to darken, clearly showing signs of radiation exposure.
the darker the film gets, the more radiation there is.
this film is often worn as a badge by haldners of radioactive substances in industry as a safety precuation.
56
what is a cloud chamber and how does it work? `
chamber that contains a super cooled, supersaturaated water or alcohol vapour
as radiation passes through, the air is ionsied with the ions serving as nucleation points in which the vapour may form droplets. these dropltes appear as 'clouds' inside the chamber
an experienced user of the device will know the alpha, beta and gamma clouds apart:
- alpha leave straight lines
- beta leave a fainter siz ziaggy pattern
- gamma leave a really faint line
57
what is a transuranic element?
an element that has a larger atomic number than uranium, that is z>92
58
whats special about transuranic elements?
- they are all radioactive
- they are all made artificially and cannot be found in nature
- they help scientists learn about the nucleus of atoms
59
what are the two main ways transuranic elements are produced?
transuranic elements are poroduced by either fision thorugh neutron bombardment or in a type of particle accelerator called a cyclotron.
60
What are the three reasons as to why ethanol is such a good solvent?
- its polar and has a high affinity to water
- it has a non polar nature and thus has a high affinity to non-polar compounds
- its non toxic to humans
61
why does ethanol have a polar nature?
the molecule contains a slightly polar hydroxyl group (-OH) group. this group encourages dipole-dipole attractions and hydrogen bonding between different compounds and thus can dissolve them
thus the OH group accounts for its high solubility in water
62
why does ethanol have a non-polar nature?
- contains a typical hydrocarbon chain with C-H covalent bonds
- can thus dissolve in other non-polar substances and may dissolve these substances themselves acting as a solvent
- dispersion forces created from these C-H bonds along with the hydrogen bonding present within the molecule help it to dissolve non polar substances
63
what are some examples of ethanol used a solvent in the real world?
- inks
- perfumes
- lacquears
- Solvent-based paints
- household cleaning products
- aftershaves
- external pharmecuticals
64
what is fermentation?
fermentation is the process by which glucose is broken down to form ethanol and carbon dioxide.
65
what are the conditions for which fermentation of glucose is promoted?
- glucose must be in solution (acqeous)
- yeast must be present
- temperature should be kept at 37 degrees celcius
- there must be a restriction of oxygen in the system
- the solution being midly acidic may stop pathogens from growing
- yeast must be alcohol tolerant
66
why does the glucose breakdown in the presence of yeast?
the yeast involved in the experiment experiences a lack of oxygen due to the conditions being anaerobic. as such, the yeast must look to the glucose as a source of energy and thus they break it down and consume it.
67
what is the molar heat of a compound?
the molar heat of cumbustion of a substance is the amound of heat liberated when one mole of that substances undergoes complete combustion at standard pressure and temperature.
68
is combustion exothermic or endothermic?
exothermic
69
what are some advantages for using ethanol as a fuel source?
- it is less volatile than petrol and hence more safe to use
- it burns more cleanly and thus produces more unwanted products such as soot and harmful pollutants such as carbon monoxide and dioxide
- its non toxic
- ethanol is a renewable resouce and is it sourced from crops such as sugar cane which can be grown in an appropriate amount of time for use
- when grown, the crops which are used to produce the ethanol absorb the carbon dioxide in the air, making the fuel more greenhouse friendly
70
what are the disadvantages of using ethanol as a fuel source?
- large areas of arable land needs to be devoted to the cultivation of suitable plants such as sugarcane. leads to errosion, deforestation, a loss of animal life, salinity problems and other environmental issues
- when used it releases less energy per mole than octane, a common fuel
- the energy required in obtaining ethanol from crops is very high, and it is fossil fuels which are burnt to provide this energy. thus ethanol isnt very environmentally friendly as once invisioned
- in some cases the energy required to obtain the ethanol can be larger than the energy released by the ethanol
- as a result of the high energy requirements for extraction, ethanol is very expensive
- competition will arise between land for crops or food. food prices could sky rocket due to no land available due to ethanol production
- large scale engine modifications would be required if ethanol would be used as a fuel in compositions larger than 20% because it can dissolve anything, polar or non-polar
71
what is my assesment of the potential of ethanol as an alternative fuel source?
ethanol has some potential to be used as an alternative fuel source to other petrochemicals, but the conts of its use outweigh th pros in my opinion, and so i do not belive it is appropriate to be used
72
how are alcohols named?
- named according to the number of carbons atoms in its longest chain
- -ol at the end indicates the series in which it belongs (suffix)
73
```
C1
C2
C3
C4
C5
C6
C7
C8
```
```
meth
eth
prop
but
pent
hex
hept
oct
```
74
what is a displacement reaction ?
a reaction where metals are displaced from solution due to a transfer of electrons between a metal and a metal ion. this occurs due to the relative difference in activity of both metals
75
whats another name for a displacement rxn?
an oxidation-reduction rxn or REDOX rxn
76
the thing that is oxidised is the...
reductant
77
the thing that is reduced is the...
oxidant
78
what is the relationship between how active a metal is and redox?
a more reactive metal compared to another metal will displace it in a redox reaction, that is, it will oxidise and give its electron(s) to the other metal, in which that metal will become reduced
79
what can i use to determine how active a metal is compared to another?
the activity series of metals
80
what is the cathode and anode in the dry cell?
zinc casing acts as the anode, and the graphite rod coated with magnese dioxide acts as the cathode
81
what is the electrolyte in a dry cell?
Ammonium chloride and zinc chloride paste along with traces of maganese dioxide
82
what is the cathode and anode in a silver oxide button cell?
cathode: graphite and silver oxide paste
anode: zinc
83
what is the electrolyte in the silver oxide button cell?
potassium hydroxide paste
84
describe the cost and practicality of a Dry cell in comparision to a button cell
- its much cheaper than a button cell
- the zinc casing and anode forms a container for the rxns
- however its non rechargable
- its more robust than the button cell and takes up more space
85
describe the dry cells impact on society
- it provided a power source for portable devices
- many appliances were then modelled around it because it was the first battery
- its used in torches, remotes, clocks and toys
86
describe the chemistry of a dry cell
- produces roughly 1.5V, slightly lower than the button cell
- voltage drops overtime so will become obsolete well before it is actually flat
- the reaction between zinc and ammonium ions is slow
- it has a poor shelf lifem and only last for 1.5years
87
decribe the environmental impact of the dry cell
-provides minimal environmental problems in dumps:
manganese(III) is readily oxidised to insoluble manganese(IV) oxide
zinc casing causes no issues
ammonium salts and carbon are harmless
-it contributes to landfil. used a lot and isnt recyclable
88
decribe the cost and practicality of the silver oxide button cell
- its small so it can be used in small devices such as watches and hearing aids
- has a long operating life (3-5 years)
- its more expensive than the dry cell as silver is a precious metal
- its non rechargable
89
decribe the chemistry of the silver oxide cell
- produces 1.6V, slightly higher than the dry cell
- has a steady voltage, doesnt deplete overtime
- long shelf life
- reduced silver produced through reduction improves the conductivity of the cell
90
describe the silver oxide cell's impact on society
- its small size, lightweight, and stable voltage allow devices such as watches and lazers to be widely available and medical appliances such as hearing aids and hear pacemakers to be used and developed
- the button cell allows the life span of many medical appliances to be extended
91
describe the silver oxide button cells impact on the environment
- doesnt often contain any highly toxic material
- its often recycled due to value of silver, less stress on landfills along with its small size
- potassium hydroxide electrolyte is caustic and can cause burns if casing is damaged
- older variations contained mercury which is a toxic heavy metal
92
what is the relative mass of alpha radiation?
4
93
what is the relative mass of beta radiation?
1/2000
94
what is the relative mass of gamma radiation?
0
95
what is the penetrative power of alpha radiation?
low
96
what is the penetrative power of beta radiation?
moderate
97
what is the penetrative power of gamma radiation?
high
98
what is the ionising power of alpha radiation?
high
99
what is the ionising power of beta radiation?
moderate
100
what is the ionising power of gamma radiation?
low
101
describe the structure of a cellulose polymer chain and and explain in terms of its properties
- cellulose is a long chain of linked glucose sugar molecles called "beta-glucose"
- present throughout the chain are hydroxly groups which undergoe hydrogen bonding with neighbouring molecules forming hard, stable crystallian regions, providing strength and the cause of its insolubility
- when glucose molecules link together to form the cellulose chain, every second glucose monomer is effectively flipped upside down. this produces a fairly linear molecule, increasing density and strength of the molecule
- cellulose is also rigid due to the bulky hydroxymethly groups on either side of each glucose monomer unit
102
what is the name of the biopolymer i have researched?
polyhydroxybutyrate (PHB)
103
what is a biopolymer?
A biopolymer is a polymer that is naturally occuring and found in living things.
104
when was PHB first studied and by who?
first studied between 1923 and 1926 by french microbiologist Maurice Lemoigne
105
what is the main organism which is used to produce PHB?
ALCALIGENES EUTROPHUS
106
how is PHB made?
PHB is formed by feeding a culture of micororganisms such as alcaligene eutrophus a nutrient rich diet until large colonies of the bacteria begin to form
glucose is then withdrawn from the diet, and the bacteria will automatically secrete PHB as an energy store, similar to body fat in humans
107
wasnt there a way to produce PHB which is more efficient?
genetic engineering techniques have enabled scientists to locate the specific gene responsible for the secretion of PHB, and transfer this gene into a more commonly known bacterium such as E.coli. easier to work with as they are more familiarly known, faster production rate
108
what are the properties of PHB?
- naturally occuring-- non toxic and renewable
- biodegradable
- biocompatible
- brittle,regid, high tensile strenght and high melting point
- good oxygen permeability
- thermoplastic
- breaks down in anaerobic conditions of landfill
109
name some uses of PHB in relation to its properties
- disposable nappies(biodegradable)
- medical stitching(biodegradable and non toxic
- packaging, bottles, bags, wrapping film (biodegradable)
110
what are some disadvantages of PHB?
- biodegradability is a disadvantage where the plastic requires to be intact long term
- high production costs limits its use (5-7x more expensive than that of petrochemical plastics)
- brittle nature limits its use
111
what are the firsts in the fermentation of glucose?
1) sugar cane or any kind of grain is crushed and grinded up with water
2) alpha-amylase is added to the starchy plant matter to break down the glucose-glucose molecules in starch, yielding maltose (performed at 77 degrees celcius) . then enzyme glucoamylase is added to split the maltose into glucose
3) yeast is then added
- provides maltase (maltose--> glucose)
- provides zymase(glucose--> ethanol)
- done in anaerobic conditions
the resultant 15% ethanol soln is then fractionally distilled to produce a 96%-98% ethanol mixture
112
describe the production of commercial radioisotopes in a nuclear reactor and give an example
suitable target nuclei are bombarded with neutrons to produce a desired isotope. this isotope may breakdown into other isotopes on occasion
eg. cobalt-60 can be made by bombarding cobalt-59 with neutrons.
113
describe the production of commercial radioisotopes in a particle accelerator(cyclotron) and give an example
a particle accelarator utlises a static magnetic field and a varying electric field to accelerate charged particles (protons for example) at high speeds into the nuclei of atoms with controlled energies in order to study nuclear rxns or to create radioisotopes
eg. technitium-99m is produced by acclerating Deuterium onto target Molybdenum-98, producing technitium-99m and an excess neutron
114
describe the use of technitium 99m in medicine
technitium 99m is a radioisotope used in medical imaging of the body, used with the brain, thyroid, lungs, kidneys, liver
115
what are the properties of technitium 99m and relate them to its uses
- the isotope emits low energy highly penetrative gamma radiation that can be picked up by a machine and converted into an image on a monitor, effectively tagging the area
- with a half life of 6 hours the exposure to the body's healthy tissue is minimised
- releases low energy emissions which minimise tissue damage
- can attach to other compounds such as tin and red blood cells to study the heart and blood vessels
116
when is cobalt 60 used in the industry?
cobalt 60 is used to gauge metal thickness and to check for cracks in metal pipes
cobalt 60 is placed on one side of the metal, with photographic film placed on the opposing side
variances in thickness, aswell as defects in the metal are then identified via the darkening of the photographic film
117
what are the properties of cobalt 60 and relate these to its uses in industry?
- half life of 5.3 years means it can be placed and used for a conveniant amount of time not requiring routine replacement
- relatively low emmision of radiation also limits the potential damage to anyone working with the radioisotope
- releases moderate/high penetrative emissions, beta and gamma, which easily pass through stuff
118
what are the conditions underwhich HDPE is made?
-normal room pressure
-temps at 60 degrees
-metal oxide catalyst called a ziegler natta catalyst -> mixture of titanium chloride and trialkluminium compound)
catalyst allows the surface polymerisation to occur encouraging a more ordered orientation of ethylene to form
119
what are the properties of HDPE?
the polymer is:
- tightly packed and of high denisty
- expresses a crystalline and rigid structure
- MP and BP higher than LDPE
- chemically resistant
120
what are the uses of HDPE?
petrol tanks
rubbish bins
plastic crates
agricultural piping
121
what is vinyl chlorides systematic name and what is its structure?
chloroethane
one of th hydrogens in ethene is replaced with a chlorine atom
122
what is viny chloride a monomer of?
polyvinylchloride or polychloroethane
123
what is styrenes systematic name and whats it structure?
phenylethene or ethnylbenzene
one of the hydrogens in ethene is replaced with a benzene ring
124
what are the uses of polymers made from vinyl chloride and relate them to their properties
-used in raincoats, shower curtains, hose pipes, drain pipes
water and flame resistant, strong
-used in electrical cable covering
does not conduct electricity
-used in insulation
does not conduct heat
125
what are the uses of polymers made from styrene and relate them to their properties
-packaging, foam drinking cups, hot food containers
blowing hot air through the polystyrene before it sets produces styrene form .fantastic heat, cold and electrical insulation
very good thermal insulator
-food containers, CD and casettes cases and plastic cups
transparent due to its few crystals in its structure
-interior of refrigerators and air conditioner housings
when rubber is dissolved in styrene before it is polymerised, the polystyrene produced is more impact resistant
126
what are the benefits of models?
- provides a simple representation to aid understanding
- demonstrates the difference between the various bonds in a molecule
- provides a physical representation of the type and quantity of atoms involved in a molecule
127
what are the limitations of models?
- relative sizes of, and distances between the atoms are unrealistic
- the dynamic nature of various molecules and their bonds is not shown
- oversimplifies the model
128
in which country is ethanol widely used?
brazil
129
whats the history and reason behind ethanol being used in brazil?
- in the 1970s the brazillian government subsidided the production of ethanol in order to reduce oil imports and stimulate employment growth during the oil crisis. they also put taxes on gasoline, making ethanol a highly profitable industry
- by using sugar kane waste to produce ethanol, approximately a third of the motor vehicles in brazil (over four million) were able to use pure ethanol was a source of fuel
- today approximately 50% of the brazillian cars are able to use 100% ethanol as fuel. the majority of the remaining vehicles use a mixture containing at least 20% ethanol
130
whats the use of ethanol in other countries like australia?
not yet profitable as the infrastructure(such as compatible engines) are limited:
- most of these countries utilise a blend containing approximately 15% ethanol as this amount can be used in any engine with no need for modification
- although further engine modifications are required before this concentration can increase, research and innovation coupled with rising petrol prices offer much incentive to see this change undergone as soon as possible
despite such potential, the viability of using ethanol as a fuel is largely limited by the costs of producing large quantities through industrial fermentation of glucose-high crops such as sugar kane
131
what are the positives of using ethanol in these particular countries?
social: its widespread use in brazil in the 1970 oil crisis helped to relieve pressure and stress
social: brazil is less worried and pressured/affected by current depleting fuel sources than other countries
environmental: in brazil, the air quality in big cities improved significantly in the 1980s
in australia, support of the use of ethanol is steadily increasing as groups, such as Australias canegrowers increasingly advocate its use
132
what are the negatives of using ethanol in these particular countries?
environmental: in brazil the requirement of land for crops resulted in mass deforestation of the amazon. a study showed that while a hectare of sugarcane can save 15 tonnes of carbon dioxide emissions a hectare of the amazon will absorbe 20 tonnes of CO2
- social: food prices increased drastically after the introduction of ethanol as land had started to be substituted by ethanol production instead of food production
- in australia, the ethanol industry is not yet profitable as the infrastructure( such as compatible engines) is limited
133
whats the assessment of the current usage of ethanol?
in brazil, the use of ethanol is quite successful as it is used with many positive affects. however, in australia, the use of ethanol is not as successful but there is potential for a thriving industry in the future as petrochemical sources continue to deplete
overall positive in brazil, not so much for the rest of the world
