Unit 1a - Products from rocks Flashcards
1
Q
What are the characteristics of the electrons in an atom?
A
- Move around the nucleus
- Negative charge
- Very tiny but cover a lot of space
- Occupy shells around the nucleus
2
Q
What happens if some electrons are added or removed from an atom?
A
The atom becomes charged and is then an ion
3
Q
What are two examples of reactions for the group 1 metals?
A
React with water to form an alkaline solution and hydrogen gas.
They react with oxygen to form an oxide.
4
Q
What are the characteristics of a nucleus in an atom?
A
- The middle of the atom
- Contains protons and neutrons
- Has a positive
- It’s very small
5
Q
Why does the nucleus of an atom have a positive charge?
A
Because it contains protons and neutrons and neutrons have no charge whereas protons have a positive one
6
Q
What charge do atoms have and why?
A
No charge because the number of protons equals the number of electrons so they cancel each other out
7
Q
What do elements consist of?
A
One type of atom only
8
Q
What decided what type of atom something is?
A
The number or protons
9
Q
What does the periodic table do to elements?
A
Puts the ones with similar properties together
10
Q
Why are the elements in each group put together?
A
Because they all have the same number of electrons in their outer shell so they have similar properties and react similarly
11
Q
What kind of gases are the elements in the final column (group 0)?
A
Noble gases
12
Q
What do the noble gases have in common?
A
Eight electrons in their outer shell apart from helium which has two so they are all stable and unreactive
13
Q
In the periodic table what is the top number (the biggest number) on an element?
A
The mass number which s the total number of protons and neutrons
14
Q
What is the bottom number on an element (the smaller one)?
A
The atomic number which tells you the number of protons and, therefore, the number of electrons.
15
Q
How do you find the number of neutrons in an atom?
A
Subtract the atomic mass from the mass number
16
Q
What model of atom do chemists like best?
A
Nuclear model
17
Q
What are shells of an electron sometimes called?
A
Energy levels
18
Q
Where are the lowest energy levels located in an atom?
A
The closest shell to the nucleus as they are always filled first
19
Q
What does the atom want to do when the outer shell is not completely full?
A
React to fill it
20
Q
What are the rules to work out electronic structure?
A
- The periodic table tells us how many protons an element has so it must have the same number of electrons
- The first shell can only take 2 electrons and the rest can take a maximum of 8
- You can work out the structure from this
21
Q
How do you make a compound?
A
Different elements react and Atoms form chemical bonds with other atoms and this forms a compound
22
Q
What does making bonds involve?
A
Atoms giving or taking or sharing electrons
23
Q
What is a compound which is formed from a metal and a non metal called?
A
Ion
24
Q
How do you form positive and negative ions?
A
The metal atom loses an electron to form a positive ion and the non metal atom gains an electron to form a negative ion
25
What do the opposite charges of ions mean?
They are strongly attracted to each other
26
What is a non metal and a metal making a bond called?
Ionic bonding
27
What is an example of an ionic bond?
NaCl because a sodium atom gives an electron to a chlorine atom
28
What does a compound consist of that is formed from non-metals?
Molecules
29
What is covalent bonding?
Non metal atoms sharing electrons with each other
30
What is an example of a covalent bond?
HCl
| A hydrogen atom bonds with a chlorine atom by sharing an electron with it
31
What are the properties of a compound in relation to the properties of their original elements?
Totally different
32
An example of a compound having completely different properties
Iron (- lustrous magnetic metal) and sulfur (a nice yellow power) react the compound formed is iron suffice and is a dull gray solid lump and doesn't behave anything like iron or sulfur
33
What is the main way of making bonds?
Heating them
34
What can compounds be?
Small molecules like water or great whopping lattices like sodium chloride
35
What is the structure of sodium chloride
A cube with sodium and chloride ions one after an other
36
What, in an equation, are the atoms at the start of the equation referred to as?
Reactant atoms
37
What, in an equation, are the atoms at the ending of an equation referred to as?
Product atoms
38
What is limestone often formed from?
Sea shells
39
What is limestone mainly?
Calcium Carbonate
40
How is limestone removed?
Quarried out of the ground
41
What is good about limestone?
It's great for making into blocks for buildings like old cathedral are often made from limestone blocks
42
What happens to limestone when it is heated?
It thermally decomposes to make calcium oxide and carbon dioxide
43
What is thermal decompostion?
When one substance chemically changes into at least two new substances when heated
44
What are the equations for thermally decomposing limestone?
Calcium carbonate --> Calcium oxide and carbon dioxide
CaCO3 --> CaO + CO2
45
When magnesium, copper, zinc and sodium carbonates are heated what happens?
They decompose in the same way as limestone e.g __carbonate --> ___oxide + carbon dioxide
46
Why might you be unable to decompose some of the carbonates from group 1 metals?
A Bunsen burner can't reach a high enough temperature to thermally decompose some of them
47
Calcium carbonate reacts with acid to form what?
Calcium salt, carbon dioxide and water
48
An example of calcium carbonate reacting with an acid
Calcium carbonate + sulfuric acid --> calcium sulfate + carbon dioxide + water
49
What does the type of salt that is produced when a carbonate is reacted with an acid depend on and an example?
The type of acid for example a reaction with hydrochloric acid would make a chloride
50
What are the other carbonates besides calcium that react with acids?
Magnesium, copper, zinc and sodium
51
What does calcium oxide reacting with water produce?
Calcium hydroxide
52
What are the equations for reacting calcium oxide with water
Calcium oxide + water --> calcium hydroxide
| CaO + H2O --> Ca(OH)2
53
What is calcium hydroxide and what can it be used for?
An alkali used to neutralise acidic soil in fields
54
What is the advantage of using calcium hydroxide over powdered limestone to neutralise acidic soil?
It works much faster
55
What can calcium hydroxide be used to test for and what are the steps?
Carbon dioxide
If you make a solution of calcium hydroxide in water (called limewater) and bubble gad through it if the solution turns cloudy carbon dioxide is present.
56
In the test for carbon dioxide using calcium hydroxide what is the cloudiness caused by?
The formation of calcium carbonate
57
What are the equations for the carbon dioxide using calcium hydroxide test
Calcium hydroxide + carbon dioxide --> calcium carbonate + water
Ca(OH)2 + CO2 --> CaCO3 + H2O
58
How do you make cement?
Powdered limestone is heated in a kiln with powdered clay to make cement
59
What can cement be Mixed with to make mortar?
Sand and water
60
What is mortar used for?
Sticking bricks together
61
What can you add to mortar?
Calcium hydroxide
62
What do you add to cement to make concrete?
Sand and aggregate (water and gravel)
63
What are the environmental problems of quarrying limestone?
1. Makes huge ugly holes which permanently change the landscape
2. Quarrying processed like blasting rocks apart with explosives make a lot of noises dust in quiet scenic areas
3. Quarrying destroys habitats of animals
4. The limestone needs to be transported away from the quarry which causes more noise and pollution
5. Waste materials go to tips
64
What are examples of making stuff from limestone causing pollution?
1. Cement factories makes lots of dust causing breathing problems for some people
2. Energy is needed to produce cement and quicklime and this will most likely come from burning fossil fuels
65
What are the positives of limestone?
1. It provides things people want like houses , roads, dyes, paints and medicines
2. Limestone products are used to neutralise acidic soil and acidity in lakes and rivers is also neutralised by limestone products
3. It is used in power stations chimneys to neutralise sulfur dioxide
4. Provide jobs and brings more money to the local economy so improvement in transport, roads, recreation facilities and health
66
What is acidity in lakes caused by?
Acid rain
67
What is a cause of acid rain?
Sulfur dioxide from power station
68
What is normally required as part of the planning permission after quarrying limestone is complete?
Landscaping and restoration of the area
69
What are usually used as building materials?
Limestone and concrete
70
Why is limestone used instead of granite or marble?
1. It is widely available
2. cheaper
3. fairly easy to cut
4. It is more hard wearing than marble but is still attractive
71
How can concrete be used to make blocks or panels?
It can be poured into moulds and these blocks or panels can be joined together
72
What is one advantage and one disadvantage of using concrete?
Very quick and cheap way of constructing buildings
| It is hideously unattractive
73
What are three advantages of limestone concrete and cement compared to wood?
They don't rot when they get wet like wood, can't get gnawed away by insects or rodents and they are fire-resistant
74
What is and advantage and disadvantage of using concrete compared to metal?
It doesn't corrode like metals but it had a fairly low tensile strength so it can crack
75
What is a way to reinforce concrete so it's stronger?
Steel bars
76
What is an example of an unreactive metal found in earth as the metal itself rather than a compound?
Gold
77
What is the definition of a metal ore?
A rock that contains enough metal to make it worthwhile extracting the metal from it
78
What is the ore in most cases?
An oxide of the metal
79
What is an example of an ore being an oxide of the metal?
Aluminium ore is called bauxite which is aluminium oxide
80
How do most metals need to be extracted from an ore?
Using a chemical reaction
81
What are two ways the economics/ profitability of a metal extraction can change over time?
1. Is the market price of a metal drops a lot it might not be worth extracting it and if the price increases it might be worth extracting more
2 as technology improves it becomes possible to extract more metal from a sample of rock than was originally possible so it might be worth extracting metal that wasn't worth extracting in the past
82
What are the threes ways metals can be extracted from their ores?
Chemically (by reduction) or by electrolysis (splitting with electricity) and sometimes by displacement reactions
83
Why do some ores have to be concentrated before the metal is extracted?
To get rid of the unwanted rocky material
84
What can electrolysis be used to do for extracted metal?
Purify the extracted metal
85
To extract a metal chemically what happens?
Reduction using carbon
86
What happens when an ore is reduced?
Oxygen is removed from it
87
An example of a metal that has been extracted from an ore by reduction using carbon?
2Fe2O3 + 3C --> 4Fe + 3CO2
| Iron (III) oxide + carbon --> iron + carbon dioxide
88
What determines whether a metal can be extracted by reduction with carbon?
The position of the metal in the reactivity series
89
What do metals higher than carbon in the reactivity series need to be extracted by?
Using electrolysis of molten compound which is expensive
90
What can metals below carbon in the reactivity series be extracted by?
Reduction using carbon
91
What is an example of an oxide that is reduced in the blast furnace?
Iron oxide is reduced in a blast furnace to make iron
92
Why can only a few metals be reduced with carbon?
Carbon can only take the oxygen away from metals which are less reactive than carbon itself
93
What do you have to pay for in extracting metals?
Special equipment, energy, labour, cost of getting the ore to the extraction plant
94
If a company had a choice of extraction methods why might they not choose the cheapest way?
To increase purity
95
Why is electrolysis much more expensive than reduction using carbon?
Because it uses a lot of energy because a high temperature is needed to melt the ore so the metal can be extracted which requires a lot of energy so it is expensive
96
Why is electrolysis used to purify copper even though it's quite expensive?
Because copper is extracted by reduction with carbon as the ore is heated in a furnace which is called smelting but the copper extracted isn't very pure and impure copper doesn't conduct electricity well so it isn't useful because a lot of copper is used to make electrical wiring so electrolysis is used to purify it and make is pure so it's a better conductor
97
What is electrolysis?
It means the splitting up with electricity and is the breaking down of a substance using electricity
98
How does electrolysis work?
It requires a liquid to conduct the electricity which is called the electrolyte which are often metal salt solution made from the ore or molten metal oxides. The electrolyte has free ions which conduct the electrics and allows the whole thing to work. Electrons are taken away by the (positive) anode and given away by the (negative) cathode. As ions gain or lose electrons they Become atoms or molecules and are released.
99
Which part in electrolysis takes away electrons?
(Positive) anode it attracts negative ions
100
Which part in electrolysis gives up electrons?
(Negative) cathode it attracts positive ions
101
How is electrolysis used to get copper? State all the steps
Electrons are pulled off copper atoms at the anode causing them to go into solution as Cu2+ ions.
Cu2+ ions near the cathode gain electrons and turn back into copper atoms.
The impurities are dropped at the anode as a sludge whilst pure copper atoms bond at the cathode.
102
What will happen if you put a reactive metal into a solution of a dissolved metal compound and why?
The reactive metal will replace the less reactive metal in the compound because the more reactive metal bonds more strongly to the non-metal bit of the compound and pushes out the less reactive metal
the
103
What is an example of a way of extracting copper using displacement?
Scrap iron can be used because if some iron is put into a solution of copper sulfate the iron will displace the less reactive copper solution and you end up with iron sulfate solution and copper metal. Any metal less reactive than copper wouldn't do anything as the more reactive metal is already in the solution.
104
Why is it important to recycle As much copper as possible?
Because the supply of copper-rich ores are limited and the demand for copper is growing which may lead to shortages in the future
105
How does bioleaching to remove copper from low grade ore work?
This uses bacteria to separators copper from copper sulfide. The bacteria get energy from the bond between copper and sulfur and separates the copper from the ore in the process. The leachate (the solution produced by the process) contains copper which can be extracted by filtering
106
How does Phytomining to remove copper from low grade ore work?
In loved growing plants in soil that contains copper as the plants can't use or get rid of the copper so it gradually builds up in the leaves and the plants can be harvested, dried and burned in a furnace so the copper can be collected from the ash left in the furnace.
107
What is an advantage and disadvantage of extracting copper using bioleaching and Phytomining?
They have a much smaller impact of the environment than the traditional methods of extracting copper as it is mining which is pretty damaging to the environment but they are slow
108
What does a good quality copper wire do?
Conduct electricity
109
Why is mining metal ore good?
Useful products can be made and provides local people with jobs and brings money to the area this means that services like trans port and health can be improved
110
Why is mining metal ore bad?
It is bad for the environment as it causes noises, scarring of the landscape and loss of habitats. Deep mine shafts can be dangerous for a long time after the mine has been abandoned
111
Why is recycling metals more important?
1. Mining and extractions takes a lot a energy which comes from burning fossil fuels
2. Fossil fuels are running out so it's important to conserve them and burning them contributes to acid rain, global dimming and climate change
3. Recycling metals only use a small fraction of the energy needed to mine and extract new metals
4. energy doesn't come cheap so recycling saves money
5. There's a finite amount of each metal in the earth so recycling saves these
6. Recycling cuts down on the amount of rubbish that gets sent to landfills
112
How much energy does recycling copper take compared to mining and extracting new copper?
Only 15%
113
Why are landfills bad?
They take up space and pollute the surroundings e.g if all aluminium cans in the UK were recycled there'd be 14 million fewer bins to empty each year
114
What are the properties of most metals?
Strong, bendy because they can be bent or hammered and great at conducting hear and electricity
115
Where are transition metals found?
Which are found in the centre block of the periodic table
116
What do metals strength and bendability make them handy for making?
Bridges and car bodies
117
What is an example of a product that metals are idea for because heat can travel through?
Saucepan
118
What does metals conductivity make them good for making?
Things like electrical wires
119
What are the properties of copper?
A good conducted of electricity so it's ideal for drawing out into electrical wires. It's hard and strong but can be bent and doesn't react with water
120
What are the properties of aluminium?
Corrosion resistant and has a low density. Pure aluminium isn't particularly strong but it forms hard strong alloys.
121
What are the properties of titanium?
Low density metal but unlike aluminium it's very strong and it is also corrosion resistant
122
Why are different metals chosen for different uses?
Because of their specific properties
123
What property of metal would you want if you were doing some plumbing?
A metal that could be bent to make pipes and tanks and is below hydrogen in the reactivity series so it doesn't react with water e.g copper
124
What property of metal would you want if you were to make an aeroplane?
Strong and can be bent into shape but also light so aluminium would be a good choice
125
What properties of metal would you want if you were to make a replacement hip?
One that won't corrode when it comes in contact with water and is also light but not too bendy so titanium is a good choice
126
What happens when a metal corrodes?
They lose their strength and hardness
127
Why do some metals corrode and how are they protected from this?
Because they are exposed to air and water and by being painted over
128
What is metal fatigue?
When metals get 'tired' when stresses and strains are repeatedly put on them over time and leads to metal breaking which can be dangerous e.g in planes
129
How do you make an alloy?
Mixing two metals together Or a metal with a non metal
130
What is the percentages of elements in iron straight from the furnace?
96% iron 4% other impurities such as carbon
131
What is iron with carbon and iron used for?
Cast iron. For making ornamental railings.
132
Why doesn't cast iron have many uses?
Because it's so brittle
133
Properties of pure iron and its atoms?
Regular arrangement of identical Atoms which can slide over each other which makes the iron soft and easily shaped but far too bendy for most uses
134
What is most pure iron changed to?
Alloys called steels
135
How is steel formed?
Adding small amounts of carbon and sometimes other metals to the pure iron
136
What are the properties and uses of low carbon steel (0.1 carbon)?
It is easily shaped used for car bodies
137
What are the properties and uses of high carbon steel (1.5% carbon)?
Very hard and inflexible for blades for cutting tools and bridges
138
What are the properties and uses of stainless steel(chromium added and sometimes nickel)?
Corrosion resistant used for cutlery and containers for corrosive substances
139
Why are alloys harder than pure metals?
Different elements have different sized atoms so when an element such as carbon is added to pure iron the smaller carbon atom will distort the layers of pure iron making it more difficult for them to slide over each other so they are harder
140
What is bronze an alloy of and its uses?
Copper and tin. It is harder than copper and used to make Medals and statues
141
What is cupronickel an alloy of and its uses?
Copper and nickel. As it is hard and corrosive it is used to make "silver coins"
142
Why are gold alloys used to make jewellery?
Because pure gold is too soft
143
What metals are used to "harden" gold and make it an alloy?
Zinc, copper, silver, palladium and Nickel
144
Why are aluminium alloys used to make aircrafts?
Aluminium has a low density but it's allowed with small amounts of other metals to strengthen it
145
How has the development of alloys improved from the past?
It used to be done by trial and error but nowadays we understand more about the properties of metals so allows can be designed for specific uses
146
What are the requirements for rust using iron?
Iron, water and air
147
How is crude oil formed?
From the buried remains of plants and animals As its a fossil fuel and over millions of years with high temperature and pleasure these remains turn to crude oil
148
How can crude oil be extracted?
Drilling and pumping
149
What is crude oil a mixture of?
Many different compounds but most are Hydrocarbons molecules
150
What does a mixture consist of?
Two of more elements or compounds that aren't chemically bonded to each other
151
What are hydrocarbons?
Fuels such as petrol and diesel made of just carbon and hydrogen
152
Why are the different elements in crude oil able to be separated out?
Because there are no chemical bonds between the different parts of a mixture so the different hydrocarbon molecules in crude oil aren't chemically bonded so they all keep their original properties like their condensing points so they can be split up
153
What method can separate out parts of a mixture in crude oil?
Physical methods e.g crude oil can be split up into its separators ftactions by fractional distillation and each fraction contains molecules with a similar number of carbon atoms to each other
154
How does the fractionating column work?
Continuously with heated crude oil piped in at the bottom. The vaporised oil rises the column and the various fractions are constantly tapped off at different levels where they condense and the top of the column is cooler than the bottom
155
How might technology advancement help us in the future?
One day it is likely we'll be able to extract oil that's too difficult and expensive to extract at the moment
156
What is crude oil mostly?
Hydrocarbons called alkanes
157
What are alkanes made up of and what is their structure?
Chains of carbon atoms surrounded by hydrogen atoms
```
H H H
| | |
H-C-C-C-H
| | |
H H H
```
158
What do different alkanes have?
Chains of different lengths
159
What are the first four alkanes?
Methane, ethane, propane and butane
My elephant peels bananas
160
What is the formula for methane/ natural gas?
CH4
H
H-C-H
H
161
What is the formula for ethane?
C2H6
H H
H-C-C-H
H H
162
What is the formula for propane?
C3H8
H H H
H-C-C-C-H
H H H
163
What is the formula for butane?
C4H10
H H H H
H-C-C-C-C-H
H H H H
164
What does each straight line in an alkanes structure show?
A covalent bond
165
What is the formula for alkanes?
CnH2n+2
E.g if an alkane has 5 carbons it's got to have (2x5)+2 = 12 hydrogens
166
How many bonds do carbon atoms and hydrogen have?
Carbon atoms form four bonds and hydrogen only form one
167
How do you know alkanes are saturated?
Because all the atoms in alkanes have formed bonds with as many other atoms as they so they are saturated
168
What are the three characteristics that a short molecule has in relation to alkanes?
1. The shorter the molecule the more runny the hydrocarbon is - it's less viscous
2 . It's also more volatile so it can turn into a gas at a lower temperature
3. The lower the temperature at which the fraction vaporises or condenses and the lower its boiling point
4. The more flammable the hydrocarbon is
169
What does flammable mean?
Easy to ignite
170
What fraction in a fractional distillation column has the lowest boiling point and why?
Refinery gas because it has the shortest molecule
171
What helps decide what a fraction is used for?
The volatility
172
Why is refinery gas perfect for bottled gas?
It is a liquid at room temperature
173
How does bottled gas work?
Refinery gas is stored under pressure as liquid in 'bottles'. When the tap on the bottle is opened the fuel vaporises and flows to the burner where it's ignited
174
Why does the petrol fraction have a high boiling point?
It has longer molecules
175
Why is petrol ideal for storing in the fuel tank of a car?
Because it's a liquid so it can flow to the engine where it's easily vaporised to mix with the air before it is ignited
176
What are viscous hydrocarbons used for?
Lubricating engine parts and for covering roads
177
Why do crude oil fractions make good fuel?
Because they burn cleanly
178
What is crude oil used in?
Cars, boats, trains, plains, central heating systems, power stations to generate electricity, raw material for making various chemicals like plastic
179
What are the alternatives to crude oil?
Electricity generated by nuclear or wind power, ethanol powered cars and solar energy to heat water
180
Why are alternatives to crude oil not always easy?
Because things tend to be set up for using oil fractions like cars are designed for petrol or diesel because it's readily available and there are filling stations all over the country with storage facilities and pumps specifically designed for these crude oil fractions therefore they are often the easiest and cheaper thing to use
181
Why is crude oil more reliable than solar and why is it used instead of nuclear?
Solar and wind won't work without the right conditions and nuclear has concerns about its safety and storing radioactive waste
182
40 years ago when did scientists think non renewable crude oil would run out by?
2000
183
Why are fossil fuels not depleted completely yet?
New oil reserves are discovered from time to time and technology is constantly improving so it's possible to extract oil that used to be too difficult to extract
184
What is the worst case scenario for when oil will run out?
In 25 years
185
What do some people say we should do with the oil and why?
Immediately stop using oil for things like transport where there are alternatives because then it can be used where it is essential like in Some chemicals and medicines
186
Why do we continue to use crude oil?
It takes time to develop alternative fuels that will satisfy all our energy needs and it'll also take time to adapt things so that the fuels can be used on a wide scale e.g different car engines or special storage tanks built
187
What is a renewable resource and examples?
Sources that won't run out e.g wind, solar and tidal power
188
When do oil spills happen and why is it bad?
As the oil is being transported by tanker and it means birds get covered in the stuff and are poisoned as they try to clean themselves and other creatures like sea otters and whales are poisoned too
189
Why is burning oil to release energy from it bad?
It is thought to be a major cause of global warming, acid rain and global dimming
190
How much of crude oil is used as a fuel?
90%
191
What happens during combustion?
Fuels such as crude oil and coal contain carbon and hydrogen. The carbon and hydrogen are oxidised so that carbon dioxide and water vapour are released into the atmosphere. Energy (heat) is also produced
192
What happens when a fuel containing sulfur impurities is burnt?
The sulfur will be released as sulfur dioxide
193
What will happen if the fuel is burnt at s high temperature?
Oxides of nitrogen will form
194
What is complete combustion?
When there's plenty of oxygen and all the fuel burns
195
What is partial combustion?
When there's not enough oxygen and some of the fuel doesn't burn
196
What is released during partial combustion?
Solid particles called particulates of soot (carbon) and I burnt fuel are released. Along with carbon monoxide which is a poisonous gas
197
How does acid rain form?
Sulfur dioxide mixes with clouds to form dilute sulfuric acid which falls as acid rain. Oxides of nitrogen also cause acid rain by forming dilute nitric acid in clouds.
198
What does acid rain do to the environment?
Causes lakes to become acidic and many plants and animals to die as a result. It kills trees and damaged limestone buildings and stone statues and there are links between acid rain and human health problems as well
199
What do the benefits of electricity and travel have to be and what have the government done?
Balanced against the environmental impacts so the governments have put in place d international agreements to reduce emissions of air pollutants like sulfur dioxide.
200
How do you reduce sulfur emissions?
Remove sulfur from fuels before they're burnt or simply reduce our usage of fossil fuels
201
What are the drawbacks of trying to reduce sulfur emissions?
It costs more and takes more energy which comes from burning more fuel releasing even more green house gases
202
What are petrol and diesel starting to be replaced by and what are power stations doing to reduce their sulfur emissions?
Low sulfur versions and power stations now have acid gas scrubbers to take harmful gases out before they releases their fumes into the atmosphere
203
Why might a country suffer from acid rain that it didn't cause?
Because pollutants like sulfur dioxide can be carried a long way in the atmosphere
204
Why is the level of carbon dioxide in the atmosphere increasing?
Because of the large amounts of fossil fuels humans burn
205
What has the increase in carbon dioxide, according to a scientific consensus, led to?
The average temperature of the earth to increase in global warming
206
What is the impact of global warming?
It is a type of climate change as it increases the earths temperature and causes other types of climate change like changing rainfall patterns and it also causes severe flooding due to polar ice caps melting
207
How much sunlight is reaching the surface compared to 59 years ago?
25% less
208
What causes global dimming?
Particles of soot and ash that are produced when fossil fuels are burnt and they reflect sunlight back into space and help produce more clouds that reflect the sunlight back into space
209
Why do some scientists not think global dimming is real?
Because they blame the change on inaccurate recording equipment
210
How is renewable ethanol made?
From plant material so is known as biofuel. Done by fermentation of the plants
211
What is ethanol used to do?
Power cars
212
What is ethanol sometimes mixed with to make a better fuel?
Petrol
213
What are the pros of using ethanol as a biofuel?
the carbon dioxide released when it is burnt is taken by the plant as it grew so it's carbon neutral, the only other product is water
214
What are the cons to using ethanol as a biodiesel?
engines need to be converted to work with ethanol fuel, not widely available fuel, if demand for it increases farmers will switch from growing food to growing crops to make ethanol which will increase food prices
215
What can biodiesel be produced by?
Vegtable oils such as rapeseed oil and soybean oil
216
What can biodiesel be mixed with to run a Diesel engine?
Ordinary diesel fuel
217
What are the pros of using biodiesel as a biofuel?
It is carbon neutral, engines don't need to be converted, it produced much less sulfur dioxide and particulates than ordinary diesel or petrol
218
What are the cons of using biodiesel as a biofuel?
We can't make enough to completely replace diesel, it's expensive, it could increase food prices if farmers decide to start growing crops for the fuel instead of food
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How do you produce hydrogen gas?
Electrolysis of water as there's plenty of water about but it takes electrical energy to split up
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Where can the energy needed to electrolyse water to make hydrogen fuel come from?
Renewable resources like solar
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What are the pros of using hydrogen fuel?
It combines with oxygen in the air to form just water so it's very clean
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What are the cons of using hydrogen fuel?
You need a special, expensive engine and hydrogen isn't widely available. You still need to use energy from another source to make it and it's hard to store
