Obtaining Energy from Fuels/Fuel Choices Flashcards
(121 cards)
1
Q
Compare and contrast stored energy in fuels and chemicals
A
Chemicals - contain stored energy
Fuels - can release stored energy easily
2
Q
State what fuels provide
A
Energy
3
Q
Define fuel
A
Substance that can be reacted with other substances to lead to the release of energy that can be harnessed for a specific purpose
4
Q
State what the SI unit of energy is
A
Joule (J)
5
Q
Define non-renewable resources
A
Those that are used faster than they can be replaced
6
Q
Provide 3 examples of non-renewable fuels
A
- Coil
- Oil
- Gas
7
Q
State what reserves of fossil fuels can be classified as
A
Limited
8
Q
Describe how fossil fuels form
A
Formed from ancient plants, animals and microorganisms
9
Q
State the energy source of fossil fuels
A
Chemical energy retained post-photosynthesis
10
Q
State what chemical energy in fossil fuels can be considered
A
Trapped solar energy
11
Q
Fossil fuel formation occurs over ________ of years
A
Millions
12
Q
Outline the energy content of (black vs brown) coal
A
Brown < Black
Lowest of all fossil fuels (approx. 30MJ/kg)
13
Q
Outline the renewability of coal
A
Non-renewable
14
Q
Outline the environmental impacts of sourcing coal
A
- wildlife habitat destruction due to land clearing
- contamination of underground water deposits by heavy metals via mine wastewater
15
Q
Outline the environmental impacts of combusting coal
A
- production of greenhouse gases CO2
- nitrogen and sulphur oxides react with water to form acid rain
- nitrogen oxides react with air at ground level to form ozone (contributing to photochemical smog)
Impacts similar to crude oil
16
Q
Compare and contrast black and brown coal
A
Black coal contains less water and a greater percentage of carbon than brown coal - therefore, it has a higher heat value (making it economical to mine)
17
Q
Outline the chemical composition of coal
A
Hydrocarbons, water, nitrogen, sulfur
18
Q
Outline the renewability of crude oil
A
Non-renewable
19
Q
Outline the chemical composition of crude oil
A
Hydrocarbons (mostly members of homologous series of alkanes), nitrogen and sulfur
20
Q
State the process used to refine crude oil
A
Fractional distillation
21
Q
State what the products of crude oil fractional distillation are
A
- LPG
- Petrol
- Kerosene
- Diesel
- Fuel oil
- Petroleum jelly
22
Q
Outline the energy content of crude oil fractional distillation products
A
Greater than coal, less than petroleum gas
23
Q
Outline the environmental impacts of sourcing crude oil
A
- habitat destruction (smaller scale to coal mining)
- water contamination via fracking
- oil spills during extraction below seabed
24
Q
Outline the environmental impacts of combusting crude oil
A
- production of greenhouse gas CO2
- nitrogen and sulphur oxides react with water to form acid rain
- nitrogen oxides react with air at ground level to form ozone (contributing to photochemical smog)
Impacts similar to coal
25
State whether crude oil is a useful fuel source
No, but it contains many useful compounds
26
Outline the chemical composition of petroleum gas
Propane and butane
27
Outline the renewability of petroleum gas
Non-renewable
28
Outline the energy content of petroleum gas
Highest of all fossil fuels (approx. 56MJ/kg)
29
Outline the environmental impacts of sourcing petroleum gas
- habitat destruction via land clearing (smaller scale to coal)
- gas leaks (methane potent greenhouse gas - 10x more powerful than CO2)
30
Outline the environmental impacts of combusting petroleum gas
- production of greenhouse gas CO2
Releases less greenhouse gases/unit energy generated than coal & oil
31
Outline the renewability of coal seam gas
Non-renewable
32
Outline the energy content of coal seam gas
Highest of all fossil fuels (like petroleum gas)
33
Outline the chemical composition of coal seam gas
Methane
34
Outline the environment impacts of sourcing coal seam gas
- habitat destruction via land clearing for drilling
- gas leaks of methane
- water contamination via fracking
- depletion of groundwater sources
35
Outline the environmental impacts of combusting coal seam gas
- production of greenhouse gas CO2
Releases less greenhouse gases/unit energy generated than coal & oil
Similar to petroleum gas
36
State how coal is sourced
Open cut mining
37
State how crude oil is sourced
Drilling through bottom of seabed/landmass
38
State from what petroleum gas is derived from
Wet natural gas or crude oil
39
State how petroleum gas is sourced
Drilling
40
State from what coal seam gas is derived
Wet natural gas
41
State how coal seam gas is sourced
Fracking of wet coal deposits underground
42
Compare and contrast wet natural gas and coal seam gas location
Wet natural gas - deposited in 'bubbles' underneath rocks
| Coal seam gas - mixed within deposits of wet coal underground known as coal seams
43
Outline the chemical composition of ethanol
CH3CH2OH
44
State how bioethanol is produced
Fermentation of glucose by yeast cells
45
Outline the energy content of bioethanol
Similar to coal
46
Outline the environmental impacts of sourcing bioethanol
- habitat clearing causing ecosystem changes that may be disadvantageous for wildlife
However, existing plantations can be utilised
47
Outline the environmental impacts of combusting bioethanol
- net production of CO2 into atmosphere
Similar to biodiesel
48
Outline the chemical composition of biodiesel
Mixture of fatty acid methyl esters (produced via modification of triglycerides)
49
Outline the energy content of biodiesel
Similar to petrol and diesel
50
Outline the environmental impacts of combusting biodiesel
- net production of CO2 into atmosphere
Similar to bioethanol
51
Outline the environmental impacts of sourcing biodiesel
- habitat clearing causing ecosystem changes that may be disadvantageous for wildlife
However, existing plantations can be utilised
52
Outline the energy content of biogas
Comparable to petroleum and coal seam gas
53
Outline the chemical composition of biogas
Mixture of gases, primarily methane and some CO2
54
Outline the renewability of biogas
Renewable
55
Outline the renewability of bioethanol
Renewable
56
Outline the renewability of biodiesel
Renewable
57
Outline the environmental impacts of sourcing biogas
Minimal if existing plantations are utilised or especially if sourced from landfill/sewage treatment plants
58
Outline the environmental impacts of combusting biogas
Carbon neutral
If methane is extracted from landfill/sewage treatment plants, this highly potent greenhouse gas will be replaced with CO2 (10 times less powerful)
59
State how biodiesel is derived
Triglycerides found in vegetable oil extracted from crops are converted into FAMEs via transesterification
60
Describe the process of transesterifcation
Triglycerides mixed with a mixture of KOH (catalyst) dissolved in methanol (reactant)
61
State from what biogas can be sourced
- Landfill (anaerobic decomposition of organic matter to produce methane)
- Sewage treatment plants (as above)
- Biomass (anaerobic digestion of decaying organic matter)
62
Describe petrodiesel
One of the products of the fractional distillation of oil
63
State whether or not petrodiesel is a pure substance
No. 75% alkanes and 25% aromatic hydrocarbons.
64
Describe aromatic hydrocarbons
Contain molecules made of six-membered carbon rings with alternating single and double bonds
65
State the range in which alkanes composing petrodiesel are found
C10H22 - C15H32
66
Compare and contrast the flow along fuel lines of biodiesel and petrodiesel
Biodiesel more viscous than petrodiesel
| thus, doesn't flow as easily through fuel lines/filters
67
Compare and contrast the cloud point of biodiesel and petrodiesel
Biodiesel has a higher cloud point than petrodiesel
68
Describe viscous
Measure of liquid's resistance to flow (thickness)
69
Describe cloud point
Temperature at which small crystals start to form
70
Describe hygroscopicity
The ability of a substance to absorb moisture from the air
71
Compare and contrast the hygroscopicity of biodiesel and petrodiesel
Biodiesel has a significantly higher hygroscopicity than petrodiesel
72
Compare and contrast the environmental impacts of biodiesel and petrodiesel
```
Combustion of biodiesel:
- lower production of CO
- lower emission of particular matter
- lower emission of unburned hydrocarbons (which could cause photochemical smog)
- higher emission of nitrogen oxides
- lower emission of sulphur oxides
to petrodiesel
```
73
Compare and contrast the length of petrodiesel and biodiesel molecules
Petrodiesel molecules are generally smaller than biodiesel molecules
74
Compare and contrast the sources of petrodiesel and biodiesel
Petrodiesel - derived from crude oil which is mined on land/at sea
Biodiesel - derived from crops (increased yield requires intensive farming)
75
Compare and contrast the environmental impacts of producing petrodiesel and biodiesel
Petrodiesel - oil refineries produce significant emissions via excess hydrocarbon combustion
Biodiesel - less emissions, however farm machinery produces CO2, high-quality farmland is used for fuel production which deteriorates soil
76
Describe the effect of cold temperatures of fuel viscosity
Petrodiesel - flow mostly continues at low temp
| Biodiesel - flow stops at high cloud point
77
State some solutions to hygroscopicity and high cloud point of biodiesel
- additives need to be added to motor fuel containing high levels of biodiesel
- service stations need to keep pumps for biodiesel warmer than surroundings
- high quality seals/fuel lines may be required
- biodiesel cannot be stored for a long period of time due to likelihood of biodegradation
78
State the issues associated with hygroscopic fuels
If water content is high, combustion can not efficiently occur
79
Describe biofuels
Fuels derived from plant materials such as grains, sugar cane, vegetable waste and vegetable oils
80
Provide 3 examples of renewable fuels
1. Biogas
2. Bioethanol
3. Biodiesel
81
Describe renewable resources
Natural resources that provide energy that can be constantly replenished
82
State how bioethanol is produced
Fermentation of sugars
83
Provide the chemical fermentation reaction of glucose
C6H12O6 - > 2CH3CH2OH + 2CO2
84
State how biodiesel is produced
Reacting vegetable oils/fats with an alcohol
85
State how biogas is produced
Anaerobic decomposition of organic matter
86
State what is generally produced in the transesterification of vegetable oils/fats
Glycerol
87
State what vegetable oils and fats contain mixtures of
Saturated
Monosaturated
Polysaturated triglycerides
88
Outline the basic structure of a triglyceride molecule
Each triglyceride molecule has three different fatty acid 'tails' attached to a glycerol backbone
89
State what is produced by the alcohol used in the transesterification of fatty acids if methanol is used
FAMEs are produced
90
Define FAMEs
Fatty acid methyl esters
91
State what the transesterification reaction requires
A catalyst to help 'snip' the links between the glycerol backbone and three fatty acids
92
Summarise the transesterification reaction using a word equation
3 methanol molecules + 1 triglyceride molecule - > 3 fatty acid methyl ester molecules + 1 glycerol molecule
93
Describe structure of unsaturated fatty acid
Double C=C bond which causes kink/bend in chain
94
Describe structure of saturated fatty acid
Single C-C bond which does not cause kink/bend in chain
95
Outline the chemical composition of glycerol
C3H8O3
96
State what chemical structure specific to glycerol allows it react with the COOH group at the end of three fatty acid molecules
Three OH groups
97
State what the purpose of three OH groups on a glycerol molecule is
Enable reactions with the COOH group at the end of the three fatty acid molecules (and the formation of the triglyceride molecule).
98
Provide the general formula of a fatty acid
CnH2n+1COOH
99
State the key structural difference between a biodiesel molecule and a molecule of petrodiesel
Biodiesel has two oxygen atoms within it
100
State the chemical composition of the two layers of biodiesel fuel
Top layer - fuel (e.g. ethanol)
| Bottom layer - glycerol and potassium hydroxide and unreacted fuel (e.g. unreacted ethanol)
101
Define flash point
Lowest temp which can yield sufficient vapor to ignite air near flammable liquid's surface.
102
State whether the conversion of liquid water to gaseous water involves the input of energy
Yes. Involves energy input.
103
Provide the relationship between the magnitude of the flash point and ease of material ignition
The lower the flash point, the easier it is to ignite the material.
104
Compare and contrast the flash point of biodiesel and petrodiesel
Biodiesel has greater flash point than petrodiesel
105
Compare and contrast the length, polarity, intermolecular forces of petrodiesel and biodiesel
Petrodiesel - small, non-polar molecules (weak dispersion forces between)
Biodiesel - long hydrocarbon chain, polar molecules, two highly electronegative oxygen atoms (dipole-dipole bonds)
106
State the effect of polar bonds in biodiesel
Increase viscosity
Increases melting point
Increases hygroscopicity
107
Provide the approximate length of a biodiesel chain
Approx. 12 to 22 carbon molecules
108
Provide the approximate length of a petrodiesel chain
Approx. 10 to 15 carbon molecules
109
State what many petrodiesel deposits are contaminated with
H2S, sulfur compounds and nitrogen oxides
110
Explain why oxygen exists in biodiesel
Petrodiesel - produced anaerobic conditions (remove oxygen from dead organic matter)
Biofuels - transesterification (fats and oils from living organic matter are broken to yield long molecules containing oxygen)
111
Describe cetane number
Measure of the quality of combustion of a fuel within the engine of a vehicle
112
Compare and contrast the cetane number of biodiesel and petrodiesel
Petrodiesel < Biodiesel
113
Compare and contrast the energy density of petrodiesel and biodiesel
Petrodiesel > Biodiesel
114
Compare and contrast the oxidative stability of petrodiesel and biodiesel
Petrodiesel > Biodiesel (less stable during long term storage)
115
Describe the oxidative stability
Measure of oil or fat resistance to oxidation
116
Compare and contrast the nitric oxide and sulfur emissions of biodiesel and petrodiesel
Biodiesel produces less sulfur emissions but more nitric oxide emission than petrodiesel.
117
Compare and contrast lubrication of biodiesel and petrodiesel
Biodiesel > Petrodiesel
118
Compare and contrast burn efficiency of biodiesel and petrodiesel, referencing chemical composition
The extra oxygen provides more efficient burn - less CO produced because of greater amount of oxygen that can produce CO2
119
Compare and contrast degradation of biodiesel and petrodiesel, referencing chemical composition
Ester group allows biodiesel to be taken up by microorganisms/exposed to light which causes spontaneously degradation
Advantage - spills
Disadvantage - storage
120
Compare and contrast the charge of biodiesel and petrodiesel, referencing chemical composition and arrangement
Oxygen atoms make biodiesel molecule polar - end of molecule near oxygen has a net negative change/end farthest has a net positive charge.
- polarity makes it easier for biodiesel to form a crystal structure (when freezing - reducing cloud point)
121
Compare and contrast the corrosive characteristics of biodiesel and petrodiesel, referencing chemical composition and arrangement
Polarity of biodiesel increases likelihood of reactions with surrounding material
Thus, biodiesel can speed up corrosion of metals - decreasing lifespan of some engine components.
