Fuels and Earth Science Flashcards
(116 cards)
1
Q
What type of resource is crude oil?
A
Non renewable
2
Q
What is our main source of hydrocarbons?
A
Crude oil
3
Q
What industry is crude oil used as a raw material in?
A
Petrochemical
4
Q
How is crude oil formed?
A
Underground at high pressures and temperatures from the buried remains of plants and animals like plankton
5
Q
What is crude oil a mixture of?
A
Different compounds that are not chemically combined
6
Q
What are most of the carbons in crude oil?
A
Hydrocarbons
7
Q
What do hydrocarbons contain?
A
Carbon and hydrogen
8
Q
What are hydrocarbons in crude oil arranged in?
A
Chains or rings
9
Q
Why can the properties of hydrocarbons change?
A
They differ in size
10
Q
What process separates crude oil?
A
Fractional distillation
11
Q
What is crude oil separated into during fractional distillation?
A
Groups of hydrocarbons with similar numbers of carbon atoms
12
Q
What are the groups crude oil is separated into called?
A
Fractions
13
Q
What are fractions?
A
Simpler, more useful mixtures of hydrocarbons that are similar lengths
14
Q
What are short chain hydrocarbons?
A
Hydrocarbons with few carbon atoms
15
Q
What are long chain hydrocarbons?
A
Hydrocarbons with lots of carbon atoms
16
Q
What is the homologous series?
A
A series of compounds with the same general formular and similar chemical properties
17
Q
What happens when carbon chains become longer?
A
The boiling point increases
18
Q
As the alkane homologous series increases, how does the carbon number differ? How many does methane have?
A
Increases by one- methane has 1
19
Q
As the alkane homologous series increases, how does the hydrogen number differ? How many does methane have?
A
By 2- methane has 4
20
Q
As the alkene homologous series increases, how does the hydrogen number differ? How many does methene have?
A
Increases by 1- methene has 1
21
Q
As the alkene homologous series increases, how does the hydrogen number differ? How many does methene have?
A
Increases by 2- methene has 2
22
Q
What are the 2 different homologous series of hydrocarbons?
A
Alkanes and alkenes
23
Q
What property of hydrocarbons affects which crude oil fraction it separates into?
A
Size
24
Q
Why do all molecules in a fraction behave in the same way?
A
They have similar chemical properties
25
Why do smaller hydrocarbon molecules have lower boiling points?
Intermolecular forces of attraction break easier than in big molecules
26
What is viscosity?
How hard it is for a liquid to flow
27
What gives hydrocarbons a higher viscosity?
Stronger forces of attraction between molecules
28
What length hydrocarbons do fractions with a higher viscosity have?
Longer
29
What length hydrocarbons do fractions with a lower viscosity have?
Shorter
30
What length hydrocarbons are easier to ignite?
Shorter
31
Why are shorter hydrocarbons usually gases at room temperature?
Lower boiling point
32
Why are longer hydrocarbons harder to ignite?
Higher boiling points
33
What state are longer hydrocarbons at room temperature?
Higher boiling points
34
What properties do long chain hydrocarbons have?
Higher boiling points and viscosity
| Less flammable
35
What properties do short chain hydrocarbons have?
Lower boiling points and viscosity
| More flammable
36
What is cracking?
When longer chain hydrocarbons are broken down into shorter chain hydrocarbons
37
Why is cracking useful?
Long chain hydrocarbons are not as useful so are broken down into more useful, short chain hydrocarbons
38
What are the properties of alkane hydrocarbon molecules?
Long and saturated
39
What are the properties of alkene hydrocarbon molecules?
Smaller and unsaturated
40
What is a thermal decomposition reaction?
When one substance is broken down into at least 2 new ones when heated
41
Why do thermal decomposition reactions take lots of energy?
Strong covalent bonds are broken down
42
What are used to speed up thermal decomposition reactions?
Catalysts
43
When does cracking occur?
After fractional distillation- the longer molecules produced are cracked into smaller ones
44
Why does cracking occur?
More demand for products like petrol and diesel than bitumen and fuel oil
45
What are the two types of cracking?
Steam and catalytic
46
What occurs during steam cracking?
Heavy, vaporised hydrocarbons are mixed with steam under high temperatures
47
What occurs during catalytic cracking?
Vaporised long chain hydrocarbons are passed over a powdered catalyst at high temperatures and are broken apart
48
What catalyst is used for catalytic cracking?
Aluminium oxide
49
What does fractional distillation separate?
Hydrocarbons with different boiling points
50
What is the process of fractional distillation?
Crude oil heated and evaporates
Goes into fractionating column and rises
Temperature gradient means it is hotter at the bottom and cooler at the top
Long chain condense at the bottom
Short chain pass up column and condense at the top
51
What happens to the fractions collected after fractional distillation?
They are processed to make end products
52
Why do shorter chain hydrocarbons condense at the top?
Lower temperatures at the top and they have lower boiling points
53
What is bitumen used for?
Surfacing roads
54
What is fuel oil used for?
Larger ships and power stations
55
What is diesel oil used for?
Cars and trains
56
What is kerosene used for?
Fuel in aircraft
57
What are the refinery gases used for?
Domestic heating and cooking
58
Why are hydrocarbons great fuels?
When you burn them the complete combustion reactions give out lots of energy
59
Is complete combustion endothermic or exothermic?
Very exothermic
60
When hydrocarbons are burned in an excess of oxygen, what are the products?
Carbon dioxide and water
61
When does incomplete combustion take place?
When there is not enough oxygen for complete combustion
62
What are the products of incomplete combustion?
Carbon dioxide, carbon monoxide and water
63
In incomplete combustion, what is the carbon produced in the form of?
Soot
64
What is carbon monoxide?
A colourless, odourless, toxic gas
65
How does carbon monoxide lead to death?
It can combine with red blood cells to stop blood carrying oxygen around the body
66
What harmful gases are produced when fossil fuels are burned?
Sulfur dioxide, carbon dioxide and nitrous oxides
67
How is sulfur dioxide produced when burning fossil fuels?
Sulfur oxidises when burned
68
Why does sulfur dioxide fall as acid rain?
It mixes with clouds forming dilute sulfuric acid
69
How do nitrogen oxides form?
When hydrocarbons are burned in a confined space where the high temperatures cause nitrogen and oxygen to react, forming nitrogen oxides
70
Pros of hydrogen
Clean, renewable and no greenhouse gases emitted
71
Why is hydrogen clean?
Only waste product is water
72
Cons of hydrogen
Hard to store and must be manufactured which is expensive and not always clean
73
Why is hydrogen not always clean?
Needs to be manufactured which uses energy from another source eg from burning fossil fuels
74
Why is hydrogen hard to store?
Must be at high pressures
75
How long ago was the earth formed?
4.6 billion years ago
76
In the earth’s early existence (1st billion years) what did the volcanoes release via eruptions?
Carbon dioxide, steam, methane, ammonia and nitrogen
77
In the earth’s early existence (1st billion years) what gas was there little of in the atmosphere?
Oxygen
78
In the earth’s early existence (1st billion years) what was gradually building up in the atmosphere?
Nitrogen
79
In the earth’s early existence (1st billion years) what gas was there most of in the atmosphere?
Carbon dioxide
80
What condensed to form oceans?
Water vapour
81
What formed carbonate precipitates?
Carbon dioxide dissolved into oceans, forming a weak acid which reacted with seawater
82
What were carbon precipitates deposited as?
Sediment
83
What did some carbonate precipitates make?
Corals and shells of organisms
84
What removed carbon dioxide from the atmosphere?
Carbonate precipitates in the oceans which marine animals removed
Photosynthesis
85
What formed nitrogen gas?
Ammonia reacting with oxygen and was released by denitrifying bacteria
86
Why did nitrogen levels rise?
It isn’t very reactive so it wasn’t being broken down
87
What evolved after oceans?
Photosynthetic algae
88
What did algae remove and produce?
Carbon dioxide and oxygen
89
What did most of the carbon dioxide get locked up in?
Fossil fuels and sedimentary rocks
90
What evolved after algae?
Plants
91
Why did early organisms get killed off?
A build up of oxygen
92
What evolved after the early organisms?
More complex organisms that made use of oxygen
93
What did the oxygen create?
Ozone layer
94
Why did the ozone layer allow more complex organisms to evolve?
Blocked harmful rays from the sun
95
History of the earth (6)
```
1- volcanoes
2- oceans
3- nitrogen builds up
4- algae
4- complex organisms
5- ozone layer
6- more complex organisms
```
96
Distribution of gases in the earth’s atmosphere today
Nitrogen = 78%
Oxygen = 21%
Other gases = 1%
97
What does the greenhouse effect do?
Keeps us warm
98
Describe the greenhouse effect
Sun emits electromagnetic radiation which passes through atmosphere
Short wavelength radiation absorbed by earth, warming us up
Some is radiated as longer wavelength, infrared radiation
Some infrared radiation is absorbed by greenhouse gases
Some is reflected back to Earth because the greenhouse gases don’t let the long wavelengths pass through
Trapped in the atmosphere, keeping us warm
Some re-emitted back into space
99
Why does the enhanced greenhouse effect occur?
If the concentration of greenhouse gases increases because more solar radiation is absorbed and less is re-emitted into space which causes the atmosphere to warm up
100
What has produced more greenhouse gases?
Human activity
101
What is global warming?
Average global temperatures increasing due the enhanced greenhouse effect
102
What is global warming a type of?
Climate change
103
What does global warming cause?
Other types of climate change like changing rainfall patterns and the melting of ice caps which causes flooding
104
What is anthropogenic?
Caused by humans
105
3 main greenhouse gases
Water vapour, carbon dioxide, methane
106
How do carbon dioxide levels increase?
Burning fossil fuels
107
How do methane levels increase?
Agriculture- growing rice in flooded fields or digestive processes of certain livestock
108
Why is less carbon dioxide removed from the atmosphere?
Deforestation means cutting down and burning trees which releases more carbon dioxide and prevents it being absorbed
109
What human activities are causing climate change?
Agriculture, deforestation, land fill sites, burning fossil fuels
110
How are land fill sites causing climate change?
More mounds of decomposing waste releases methane
111
What could cause rising sea levels, leading to flooding and erosion of coastal regions?
Melting polar ice sheets and glaciers
112
Meteorological effects of climate change
Higher frequency and severity of storms, heatwaves and droughts
113
How would the amount of water change due to climate change?
Availability would change
114
What would there be shortages of due to climate change?
Food
115
What could increasing temperatures change the distribution of?
Animals
116
Ways to estimate climate change
Fossils, tree rings, gas bubbles trapped in ice cores, pollen
