Fuels - heinmann

Question 1

define fuels

Answer 1

A fuel is a substance with stored energy that can be released relatively easily for
use as heat or power

Question 2

non renewable resources…

Answer 2

are those that are used faster than they can be replaced

Question 3

where did organic matter in fossil fuels get its energy and what can this energy considered to be

Answer 3

organic matter retains some of the energy that plants first accumulated by photosynthesis. chem energy can be considered to be trapped solar energy

Question 4

3 examples of non renewable fuels

Answer 4

coal, oil and natural gas

Question 5

how are fossil fuels made

Answer 5

from organic matter buried under tonnes of mud, sand and rock; undergoing complex chemical changes

Question 6

wood is ___ percent carbon

Answer 6

50

Question 7

what happens as wood turns into coal

Answer 7

carbon content increases
proportion of hydrogen and oxygen decreases

Question 8

what does coal contain

Answer 8

coal is a mixture of large molecules of carbon hydrogen, nitrogen, sulfur and other elements

Question 9

what effect does the water in coal have when it is burnt

Answer 9

the energy released causes the water to evaporate, reducing the amount of net heat released

Question 10

amount of water in coal ____ as it changes from wood to coal

Answer 10

decreases

Question 11

why is black coal a better source of fuel compared to peat

Answer 11

contains the least water and therefore the highest
percentage of carbon

Question 12

peat is ___ percent carbon and releases ___ of heat

Answer 12

60 25 kj/g

Question 13

brown coal is ___ percent carbon and releases ___ of heat

Answer 13

70 30kj/g

Question 14

black coal is ___ percent carbon and releases ___ of heat

Answer 14

90 35 kj/g

Question 15

crude oil is a mixture of

Answer 15

hydrocarbon molecules that are mostly
members of the homologous series of alkanes

Question 16

alkanes are

Answer 16

hydrocarbons with
the general formula Cn
H2n+2.
Alkanes are commonly found in crude oil

Question 17

how is crude oil made useful

Answer 17

by fractional distillation, bcz crude oil isnt useful but contains useful compounds.
fraction is still a
mixture of hydrocarbon compounds.
it doesnt produce pure substances.
fractions can be used as fuels, or treated
further to produce more specific products through chemical processes.

Question 18

components of natural gas

Answer 18

mostly methane. small amounts of ethane and propane. may also have water, sulfur, nitrogen and co2

Question 19

where can natural gas be found

Answer 19

1. gas reservoirs - trapped between layers of rock
2. component of petroleum deposits
3. as CSG - coal seam gas - in coal deposits
4. as shale gas - trapped in shale rock

Question 20

what is the chem equation for photosynthesis

Answer 20

6CO2(g) + 6H2O(l) → C6H12O6(aq) + 6O2(g)

Question 21

what are biofuels

Answer 21

renewable fuels derived from plant materials such as
grains (maize, wheat, barley) sugar cane, vegetable waste, and vegetable oils.

Question 22

what are the 3 main types of biofuels

Answer 22

biogas, bioethanol and biodiesel

Question 23

how is bioethanol produced
what is the reaction

Answer 23

enzymes catalyse the breakdown of starch in grain crops to glucose. other yeast enzymes convert the glucose and other small molecules into ethanol and co2 in the fermentation reaction:
C6H12O6(aq) → 2CH3CH2OH(aq) + 2CO2(g).
it is then distilled to remove the water to form pure bioethanol

Question 24

what are biofuels

Answer 24

gas produced from organic waste by anaerobic bacteria

Question 25

how are biofuels produced

Answer 25

break down of complex carbs and proteins into simple c02 and methane by anaerobic bacteria in a digester. rotting rubbish and waste is used.

Question 26

what are the main components of biofuel

Answer 26

methane and co2

Question 27

what are biodiesels

Answer 27

mixtures of organic compounds called esters made by chem reactions between animal fats or vege oils and alcohol, most commonly methanol CH3OH. for oils usually soyabean, canola or palm oil are used.

Question 28

give examples of renewable fuel sources

Answer 28

bioethanol, biodiesel, biogas

Question 29

give examples of non renewable fuel sources

Answer 29

coal, oil, LPG, natural gas, coal seam gas

Question 30

why is it necessary to use fractional distillation to treat crude oil

Answer 30

Crude oil consists of a range of hydrocarbons with different boiling temperatures. Fractional distillation is needed to separate them. 1.2 Fossil

Question 31

what kind of reaction occurs to form biodiesel

Answer 31

Transesterification reaction between the triglycerides (fats) and alcohol usually methane

Question 32

what 3 factors are crucial to ensure biofuels are sustainable

Answer 32

food vs fuel - production of biofuels shouldn't reduce amount of food available. feedstock for biofuels should be waste materials or non edible plant material land requirements - need 100M hectares to grow enough biofuels energy input vs energy output - The total amount of energy required to grow, collect, and convert the feedstock into a usable biofuel should only represent a small percentage of the total energy available from combustion of the biofuel.

Question 33

how is coal formed

Answer 33

by decaying organic matter in sediments over millions of years

Question 34

how is natural gas formed

Answer 34

by decomposition of plants and animals over millions of years

Question 35

why is it so difficult to make a carbon neutral bio fuel

Answer 35

Seeds need to be bought, transported, and planted using machinery that would normally use non-renewables.

Question 36

which fuel is a mixture of methyl esters

Answer 36

biodiesel

Question 37

what is the bi product of a traserstification reaction

Answer 37

glycerol