Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Chemistry 6 - Organic Chemistry > Alternative Fuels > Flashcards

Alternative Fuels Flashcards

You may prefer our related Brainscape-certified flashcards:
Periodic Table flashcards Chemistry 101 flashcards AP® Chemistry flashcards Organic Chemistry 101 flashcards
1
Q

what other two problems come to mind when relying on the combustion of alkanes for energy, other than pollution

A
  • the depletion of natural resources

- global warming and climate change

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is the name given to new fuels being created that are an alternative to fossil fuels

A

biofuels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

why are these fuels called biofuels

A
  • because they are obtained from living matter that has died recently
  • rather than millions of years ago
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is the most common biofuel that is and always has been used and why is ti considered one

A
  • wood

- it is one because it can be grown quickly (at least a lot quicker than millions of years)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what are examples of non-renewable sources of energy

A
  • the fossil fuels

- like coal, gas, and crude oil

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what are examples of renewable sources of energy

A
  • biofuels

- but also sunlight, wind, tidal or geothermal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what does it mean if a source of fuel is completely carbon neutral

A
  • it uses or absorbs the same amount of carbon dioxide it produces when turned into fuel
  • meaning the net amount of carbon dioxide released by that fuel is 0
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what is an advantage of using biofuels rather then fossil fuels when it comes to carbon neutrality

A
  • biofuels are a lot more carbon neutral than fossil fuels
  • meaning they produce less CO2
  • and therefore contribute less to climate change
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

why are biofuels more carbon neutral

A
  • when some form of vegetation is grown it absorbs CO2 from the atmosphere (photosynthesis)
  • however when it is burned and used a fuel it releases some CO2
  • although, because it initially absorbs CO2 its net release of CO2 would be less than a fossil fuels
  • which doesnt absorb CO2
  • making it closer to carbon neutral than fossil fuels
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

where does the carbon dioxide from the air go when absorbed and why does it turn into CO2 again when the plant is burned

A
  • the CO2 from the air is basically split into O2 which is released and C which becomes part of the structure of the plant
  • when burned, the carbon combusts with the oxygen
  • forming CO2 again which is released
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

some fossil fuels are formed from trees. these trees absorbed CO2 when they were alive, so why arent they considered to be carbon neutral to some extent

A
  • the carbon dioxide that they absorbed was from the atmosphere millions of years ago
  • at this time the amount of CO2 in the atmosphere was much higher
  • in other words, it doesnt count as the atmospheres were too different for there to be a comparison
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what are the two types of biofuels we need to know about

A
  • biodiesel

- bioalcohols

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

although a plant may absorb the same amount of CO2 it releases when it is burned and turned into fuel, why cant it, as a product, still be considered carbon neutral

A
  • because even more CO2 is produced in the process of creating and transporting the fuel
  • such as harvesting, transporting to a factory, being processed in a factory then being transported to the sale point
  • all these steps require energy
  • and so are therefore releasing CO2
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

where would you find the starting materials for making biodiesel

A
  • vegetable oils

- such as those obtained from rapeseed and sunflowers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is the most common bioalcohol

A

bioethanol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what was the good old way of producing ethanol

A
  • through fermentation
  • which involves fermenting sugars into alcohol
  • you use yeast that contain enzymes to produce it
17
Q

why is fermentation an ineffective way of producing ethanol

A
  • there is an upper limit to the concentration of the ethanol in the solution (20%) before the yeast die
  • the ethanol then has to be separated from water using distillation before it can be used a fuel
  • this separation requires a lot of energy
18
Q

what actually is bioethanol then

A
  • ethanol produced in a different way

- involving bacteria rather than enzymes

19
Q

what are the advantages of using bacteria rather than yeast containing enzymes for the fermentation

A
  • it is now possible to use a much wider range of plants (sugars) and also plant waste
  • the upper amount of ethanol that can be obtained from a given amount of starting material is increasing
  • this is much higher than traditional fermentation
20
Q

what is the main source of ethanol used in cars made from

A

corn

21
Q

why are some people against the use of corn as a source of fuel

A

because it could be used to feed people insteaed

22
Q

what are the four main factors of any biofuel that need to be taken into consideration when producing it

A
  • land use
  • yield
  • manufacture and transport
  • carbon neutrality
23
Q

why does land use need to be considered

A
  • you need to know how much land will be used to grow the crop
  • should the land be used for other purposes
  • or even to feed people
24
Q

why does yield need to be considered

A
  • you need to know how much of a crop can be grown in a given piece of land
  • and how quickly it grows
  • you can also think about what percentage of carbon and hydrogen atoms in the crop end up in the fuel
25
Q

why does the manufacturing and transport need to be considered

A
  • you need to know how much energy in total is used growing the crop
  • along with processing and transporting
26
Q

why do you need to consider carbon neutrality

A

you need to know how close to being carbon neutral the biofuel is

27
Q

how does the land use between biofuels and fossil fuels compare

A
  • biofuels need a lot of land to grow
  • which in some cases take away land that could be used for growing food
  • whereas fossil fuels dont need land
  • as it comes from underground sources
28
Q

how does the yield between biofuels and fossil fuels compare

A
  • the yield for biofuels is low but increasing

- whereas for fossil fuels its very high

29
Q

how does the manufacturing and transportation processes between biofuels and fossil fuels compare

A
  • biofuels dont have any exploration or drilling costs
  • however there a substantial costs of growing, processing and transport
  • fossil fuels have very high exploration and drilling costs
  • processing and transport costs are low
30
Q

how does the carbon neutrality between biofuels and fossil fuels compare

A
  • biofuels are much closer to being carbon neutral

- whereas fossil fuels are not carbon neutral

Chemistry 6 - Organic Chemistry (20 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions