C2 - Chemical Resources Flashcards
(180 cards)
1
Q
C2 - Chemical Resources
What is the crust?
A
The Earth’s outer layer of solid rock. Average depth of 20km
2
Q
C2 - Chemical Resources
What is the lithosphere?
A
It includes the crust and upper part of the mantle. It is made up of a jigsaw of tectonic plates and is cold and rigid - over 100km thick in places.
3
Q
C2 - Chemical Resources
What is the mantle?
A
Solid section between the crust and core. Very rigid and temperature increases. Becomes less rigid and flows very slowly - semi liquid.
4
Q
C2 - Chemical Resources
What is the core?
A
It is just over half the Earth’s radius. 2 parts - inner core (solid) and outer core (liquid).
5
Q
C2 - Chemical Resources
What causes tectonic plates to move?
A
Radioactive decay creates lots of heat which creates convection currents in the mantle, causing the plates of the lithosphere to move.
6
Q
C2 - Chemical Resources
What are tectonic plates?
A
Big rocky rafts that float on the mantle because they are less dense. Move very slowly - about 2.5cm per year.
7
Q
C2 - Chemical Resources
What can tectonic plates cause?
A
Earthquakes and volcanoes where the plates meet, caused by movement of the plates against each other.
8
Q
C2 - Chemical Resources
Why is it difficult to study the Earth’s inner structure?
A
The crust is too thick to drill through.
9
Q
C2 - Chemical Resources
How can scientists study the Earth’s structure?
A
Using seismic waves produced by earthquakes or man made explosions. Measure the time it takes for them to travel through the Earth and where they are detected.
10
Q
C2 - Chemical Resources
What are the two types of seismic wave?
A
P-Waves which can only travel through solids and liquids. S-Waves can only travel through solids.
11
Q
C2 - Chemical Resources
How are volcanoes formed?
A
As an oceanic plate is forced down, it melts and starts to rise. Molten rock (magma) from the mantle emerges through crust and boils over - sometimes violently.
12
Q
C2 - Chemical Resources
Which plate is denser?
A
Oceanic plate
13
Q
C2 - Chemical Resources
What is subduction?
A
When tectonic plates collide a dense oceanic plate is forced under a less dense continental plate.
14
Q
C2 - Chemical Resources
Which igneous rock is formed from volcanoes with runny lava and a fairly safe eruption?
A
Iron-rich basalt
15
Q
C2 - Chemical Resources
Which igneous rock is formed from volcanoes with thick lava and an explosive eruption?
A
Silica-rich Rhyolite
16
Q
C2 - Chemical Resources
Why is it tricky to predict a volcanic eruption?
A
Volcanoes are unpredictable - scientists may only be able to say an eruption is more likely, not certain.
17
Q
C2 - Chemical Resources
How are sedimentary rocks formed?
A
Layers of sediment laid down in lakes or seas which get buried over millions of years, squeezing out the water. Fluid flowing through pores deposit natural mineral cement.
18
Q
C2 - Chemical Resources
What is the word equation for thermal decomposition of limestone?
A
calcium carbonate → calcium oxide + carbon dioxide
19
Q
C2 - Chemical Resources
What is the symbol equation for thermal decomposition of limestone?
A
CaCO₃ → CaO + CO₂
20
Q
C2 - Chemical Resources
How are metamorphic rocks formed?
A
Heat and pressure on sedimentary or igneous rocks over a long time. As long as they don’t melt they are metamorphic.
21
Q
C2 - Chemical Resources
What is an example of a metamorphic rock?
A
Marble - formed from limestone. The heat and pressure breaks down limestone so it reforms as small crystals making marble harder and it has more texture.
22
Q
C2 - Chemical Resources
Why are ignous rocks very hard?
A
They contain different minerals in randomly arranged interlocking crystals.
23
Q
C2 - Chemical Resources
What is an example of an igneous rock?
A
Granite - ideal for steps and buildings
24
Q
C2 - Chemical Resources
How are aluminium and iron made?
A
They are extracted from their ores.
25
# C2 - Chemical Resources
What is glass made from?
Heat up limestone (calcium carbonate), sand (silicon dioxide) and soda (sodium carbonate) until it melts.
26
# C2 - Chemical Resources
What are bricks made from?
Clay. It is initially soft when dug up but is hardened by very high temperatures.
27
# C2 - Chemical Resources
How can cement be made?
Powdered clay containing aluminium and silicates, and powdered limestone are roasted to make a complex mixture of calium and aluminium silicates.
28
# C2 - Chemical Resources
How is concrete made?
Cement is mixed with sand, aggregate (gavel) and water.
29
# C2 - Chemical Resources
What is reinforced concrete made of?
Concrete and solid steel supports - e.g. Steel rods. Because of this it is a composite material.
30
# C2 - Chemical Resources
Why is reinforced concrete a better construction material?
It combines the hardness of concrete with the flexibility and strength of steel.
31
# C2 - Chemical Resources
What are the environmental impacts of extracting rocks?
Quarrying uses land/destroys habitats and costs money to return it to new. Transporting rocks causes noise and pollution. Process produces dusta nd noise. Old sites are dangerous - disused mines are known to collapse (causing subsidence)
32
# C2 - Chemical Resources
What does electrolysis mean?
Splitting up with electricity
33
# C2 - Chemical Resources
What charge does the anode have?
Positive
34
# C2 - Chemical Resources
What charge does the cathode have?
Negative
35
# C2 - Chemical Resources
What is the reaction at the cathode for electrolysis of copper?
Cu²⁺ + 2e⁻ → Cu
36
# C2 - Chemical Resources
What is the reaction at the anode for electrolysis of copper?
Cu → Cu²⁺ + 2e⁻
37
# C2 - Chemical Resources
What type of reaction takes place at the cathode?
REDUCTION - electrons are gained
38
# C2 - Chemical Resources
What type of reaction takes place at the anode?
OXIDATION - electrons are lost
39
# C2 - Chemical Resources
Why is recycling copper better than extracting new?
Cheaper than mining and extracting from ores. Recycling uses 15% of the energy that extracting new requires.
40
# C2 - Chemical Resources
What are the issues with recycling copper?
It is difficult to convince people that the effort is worth it and for them to sort their rubbish. Sorting out the copper from other metals takes time and energy.
41
# C2 - Chemical Resources
What is an alloy?
A mixture of a metal other elements. They can can be two or more different metals or they can be mixture of a metal and non metal.
42
# C2 - Chemical Resources
What is steel?
An alloy of iron and carbon. It is harder and stronger than iron. Steel is less likely to rust whereas iron would.
43
# C2 - Chemical Resources
What is bronze an alloy of and what are its uses?
Copper and zinc. Brass is harder than either material alone and can be used in musical instruments and fixtures and fittings like screws.
44
# C2 - Chemical Resources
What is solder an alloy of and what are its uses?
Lead and tin - because it solidifies as it cools it is used to solder things together.
45
# C2 - Chemical Resources
What is amalgam an alloy of and what are its uses?
Mercury - a large scale use is in dentistry.
46
# C2 - Chemical Resources
What is nitinol?
The name given to a family of alloys of nickel and titanium that have shape memory.
47
# C2 - Chemical Resources
What alloy can be used to make spectacles?
Nitinol as the frames can be bent or sat on but still return to their normal shape.
48
# C2 - Chemical Resources
What is the word equation for the rusting of iron?
iron + oxygen + water → hydrated iron (III) oxide
49
# C2 - Chemical Resources
What factors increase the reaction in the rusting of iron?
If the water is acidic or salty.
50
# C2 - Chemical Resources
Why doesn't aluminium corrode?
It reacts very quickly with oxygen in the air to form aluminium oxide which becomes a protective layer stopping any more reaction taking place.
51
# C2 - Chemical Resources
What are the advantages of aluminium over steel?
It has a lower density, making the car lighter and giving a better fuel economy. Also it corrodes less so will have a longer lifetime.
52
# C2 - Chemical Resources
What is the disadvantage of using aluminium to make car bodies?
It is much more expensive than iron or steel.
53
# C2 - Chemical Resources
What part of a car is steel good for?
Bodywork because it is strong and can be hammered into sheets and welded together.
54
# C2 - Chemical Resources
What part of a car is aluminium good for?
Parts of the engine - it is strong and low density so using it reduces the overall weight.
55
# C2 - Chemical Resources
What part of a car is glass good for?
Its transparency is used in the windscreens and windows.
56
# C2 - Chemical Resources
What part of a car is plastic good for?
It is light and hard wearing, making it useful for internal coverings on doors and dashboards. Also as electrical insulators on wires.
57
# C2 - Chemical Resources
What part of a car are fibres good for?
Natural and synthetic are hard wearing and are used to cover the seats and floor.
58
# C2 - Chemical Resources
What is the European Law for recycling cars?
85% of the materials in a car must be recyclable - rising to 95% by 2015
59
# C2 - Chemical Resources
What is the biggest problem with recycling cars?
All the non-metal parts must be separated before they are recycled.
60
# C2 - Chemical Resources
Describe universal indicator...
A combination of dyes that changes colour gradually as the pH changes.
61
# C2 - Chemical Resources
What is phenolphthalein an example of?
A sudden change indicator - it goes from colourless to pink when the pH rises above 8.
62
# C2 - Chemical Resources
What is an acid?
A substance with a pH less than 7. Acids form H⁺ ions in water.
63
# C2 - Chemical Resources
What is pH a measure of?
The concentration of H⁺ ions
64
# C2 - Chemical Resources
What is a base?
A substance with a pH over 7 and is soluble in water. They form OH⁻ ions in water.
65
# C2 - Chemical Resources
What is the word equation for neutralisation?
acid + base → salt + water
66
# C2 - Chemical Resources
What is the ionic equation for neutralisation?
H⁺ + OH⁻ ⇌ H₂O
67
# C2 - Chemical Resources
What are the word equations for metal oxides/hydroxides?
acid + metal oxide/hydroxide → salt + water
68
# C2 - Chemical Resources
Complete: acid + carbonate…
→ salt + water + carbon dioxide
69
# C2 - Chemical Resources
What is the word equation for acids and ammonia?
Acid + ammonia → ammonium salt
70
# C2 - Chemical Resources
What are the 3 essential elements in fertilisers and what are they needed for?
Nitrogen - making proteins (amino acids) Phosphorous - respiration and growth Potassium - helps enzymes needed for photosynthesis and respiration.
71
# C2 - Chemical Resources
What must a fertiliser be able to do in order to be taken up by roots?
dissolve in water
72
# C2 - Chemical Resources
Give 4 examples of fertilisers…
Ammonium nitrate, ammonium sulfate, ammonium phosphate, potassium nitrate.
73
# C2 - Chemical Resources
What is the issue with fertilisers?
Eutrophication
74
# C2 - Chemical Resources
What is eutrophication?
Fertilisers run off into rivers and streams, increasing levels of nitrates and phosphates. Algae uses these nutrients to multiply rapidly - algael bloom, blocking off sunlight to plants meaning they die. Aerobic bacteria which eats dead plants multiply and use all oxygen, killing fish and insects.
75
# C2 - Chemical Resources
What does methyl orange indicator do?
Turns from yellow to red when alkali is neutralised (used in making ammonium nitrate)
76
# C2 - Chemical Resources
How is ammonium nitrate made?
Titration - methyl orange used. Nitric acid added to ammonia - goes from yellow to red. Evaporate solution until a little solution left - leave to crystallise. To get pure, note amount of acid needed and repeat but without indicator.
77
# C2 - Chemical Resources
What is the equation for the Haber process?
N₂ + 3H₂ ⇌ 2NH₃
78
# C2 - Chemical Resources
Where do the reactants for the Haber process come from?
Nitrogen - from the air (makes up 78% of air) Hydrogen - from cracking of oil fractions or natural gas
79
# C2 - Chemical Resources
What are the industrial conditions for making ammonia?
Pressure - High (200 atmospheres) Temperature - 450°C Catalyst - Iron
80
# C2 - Chemical Resources
Why is the pressure high in the Haber Process?
It favours the forward reaction and this high pressure increases the % yield of ammonia.
81
# C2 - Chemical Resources
Why is a high temperature used in the Haber process?
It favours the reverse reaction - so a high temperature decreases the % yield. 450 is optimum because it gives a fast reaction rate and a reasonable % yield (compromise).
82
# C2 - Chemical Resources
What happens to unused hydrogen and nitrogen when making ammonia?
It is recycled - so nothing is wasted.
83
# C2 - Chemical Resources
Why is an iron catalyst used in the Haber Process?
It makes the reaction go faster which gets it to its equilibrium proportions more quickly - but doesn’t affect the position of equilibrium or % yield.
84
# C2 - Chemical Resources
What are optimum conditions?
Those that give the lowest production costs.
85
# C2 - Chemical Resources
What 5 factors affect production cost?
Price of energy, cost of raw materials, labour costs/wages, plant costs (equipment), rate of production
86
# C2 - Chemical Resources
What is solution mining?
Pumping hot water underground which dissolves the salt and the salt solution is forced to the surface because of the water pressure.
87
# C2 - Chemical Resources
What is the issue with salt mining?
The holes must be filled in otherwise it will cause subsidence where the land collapses and slides in to the hole.
88
# C2 - Chemical Resources
What is produced in the electrolysis of brine?
Hydrogen gas, chlorine gas and sodium hydroxide.
89
# C2 - Chemical Resources
What is produced at the anode during the electrolysis of brine? (including half-equations)
Chlorine gas: 2Cl⁻ - 2e⁻ → Cl₂ OXIDATION
90
# C2 - Chemical Resources
What is produced at the cathode during the electrolysis of brine? (including half-equations)
Hydrogen gas: 2H⁺ + 2e⁻ → H₂ REDUCTION
91
# C2 - Chemical Resources
The Earth's outer layer of solid rock. Average depth of 20km
What is the crust?
92
# C2 - Chemical Resources
It includes the crust and upper part of the mantle. It is made up of a jigsaw of tectonic plates and is cold and rigid - over 100km thick in places.
What is the lithosphere?
93
# C2 - Chemical Resources
Solid section between the crust and core. Very rigid and temperature increases. Becomes less rigid and flows very slowly - semi liquid.
What is the mantle?
94
# C2 - Chemical Resources
It is just over half the Earth's radius. 2 parts - inner core (solid) and outer core (liquid).
What is the core?
95
# C2 - Chemical Resources
Radioactive decay creates lots of heat which creates convection currents in the mantle, causing the plates of the lithosphere to move.
What causes tectonic plates to move?
96
# C2 - Chemical Resources
Big rocky rafts that float on the mantle because they are less dense. Move very slowly - about 2.5cm per year.
What are tectonic plates?
97
# C2 - Chemical Resources
Earthquakes and volcanoes where the plates meet, caused by movement of the plates against each other.
What can tectonic plates cause?
98
# C2 - Chemical Resources
The crust is too thick to drill through.
Why is it difficult to study the Earth's inner structure?
99
# C2 - Chemical Resources
Using seismic waves produced by earthquakes or man made explosions. Measure the time it takes for them to travel through the Earth and where they are detected.
How can scientists study the Earth's structure?
100
# C2 - Chemical Resources
P-Waves which can only travel through solids and liquids. S-Waves can only travel through solids.
What are the two types of seismic wave?
101
# C2 - Chemical Resources
As an oceanic plate is forced down, it melts and starts to rise. Molten rock (magma) from the mantle emerges through crust and boils over - sometimes violently.
How are volcanoes formed?
102
# C2 - Chemical Resources
Oceanic plate
Which plate is denser?
103
# C2 - Chemical Resources
When tectonic plates collide a dense oceanic plate is forced under a less dense continental plate.
What is subduction?
104
# C2 - Chemical Resources
Iron-rich basalt
Which igneous rock is formed from volcanoes with runny lava and a fairly safe eruption?
105
# C2 - Chemical Resources
Silica-rich Rhyolite
Which igneous rock is formed from volcanoes with thick lava and an explosive eruption?
106
# C2 - Chemical Resources
Volcanoes are unpredictable - scientists may only be able to say an eruption is more likely, not certain.
Why is it tricky to predict a volcanic eruption?
107
# C2 - Chemical Resources
Layers of sediment laid down in lakes or seas which get buried over millions of years, squeezing out the water. Fluid flowing through pores deposit natural mineral cement.
How are sedimentary rocks formed?
108
# C2 - Chemical Resources
calcium carbonate → calcium oxide + carbon dioxide
What is the word equation for thermal decomposition of limestone?
109
# C2 - Chemical Resources
CaCO₃ → CaO + CO₂
What is the symbol equation for thermal decomposition of limestone?
110
# C2 - Chemical Resources
Heat and pressure on sedimentary or igneous rocks over a long time. As long as they don't melt they are metamorphic.
How are metamorphic rocks formed?
111
# C2 - Chemical Resources
Marble - formed from limestone. The heat and pressure breaks down limestone so it reforms as small crystals making marble harder and it has more texture.
What is an example of a metamorphic rock?
112
# C2 - Chemical Resources
They contain different minerals in randomly arranged interlocking crystals.
Why are ignous rocks very hard?
113
# C2 - Chemical Resources
Granite - ideal for steps and buildings
What is an example of an igneous rock?
114
# C2 - Chemical Resources
They are extracted from their ores.
How are aluminium and iron made?
115
# C2 - Chemical Resources
Heat up limestone (calcium carbonate), sand (silicon dioxide) and soda (sodium carbonate) until it melts.
What is glass made from?
116
# C2 - Chemical Resources
Clay. It is initially soft when dug up but is hardened by very high temperatures.
What are bricks made from?
117
# C2 - Chemical Resources
Powdered clay containing aluminium and silicates, and powdered limestone are roasted to make a complex mixture of calium and aluminium silicates.
How can cement be made?
118
# C2 - Chemical Resources
Cement is mixed with sand, aggregate (gavel) and water.
How is concrete made?
119
# C2 - Chemical Resources
Concrete and solid steel supports - e.g. Steel rods. Because of this it is a composite material.
What is reinforced concrete made of?
120
# C2 - Chemical Resources
It combines the hardness of concrete with the flexibility and strength of steel.
Why is reinforced concrete a better construction material?
121
# C2 - Chemical Resources
Quarrying uses land/destroys habitats and costs money to return it to new. Transporting rocks causes noise and pollution. Process produces dusta nd noise. Old sites are dangerous - disused mines are known to collapse (causing subsidence)
What are the environmental impacts of extracting rocks?
122
# C2 - Chemical Resources
Splitting up with electricity
What does electrolysis mean?
123
# C2 - Chemical Resources
Positive
What charge does the anode have?
124
# C2 - Chemical Resources
Negative
What charge does the cathode have?
125
# C2 - Chemical Resources
Cu²⁺ + 2e⁻ → Cu
What is the reaction at the cathode for electrolysis of copper?
126
# C2 - Chemical Resources
Cu → Cu²⁺ + 2e⁻
What is the reaction at the anode for electrolysis of copper?
127
# C2 - Chemical Resources
REDUCTION - electrons are gained
What type of reaction takes place at the cathode?
128
# C2 - Chemical Resources
OXIDATION - electrons are lost
What type of reaction takes place at the anode?
129
# C2 - Chemical Resources
Cheaper than mining and extracting from ores. Recycling uses 15% of the energy that extracting new requires.
Why is recycling copper better than extracting new?
130
# C2 - Chemical Resources
It is difficult to convince people that the effort is worth it and for them to sort their rubbish. Sorting out the copper from other metals takes time and energy.
What are the issues with recycling copper?
131
# C2 - Chemical Resources
A mixture of a metal other elements. They can can be two or more different metals or they can be mixture of a metal and non metal.
What is an alloy?
132
# C2 - Chemical Resources
An alloy of iron and carbon. It is harder and stronger than iron. Steel is less likely to rust whereas iron would.
What is steel?
133
# C2 - Chemical Resources
Copper and zinc. Brass is harder than either material alone and can be used in musical instruments and fixtures and fittings like screws.
What is bronze an alloy of and what are its uses?
134
# C2 - Chemical Resources
Lead and tin - because it solidifies as it cools it is used to solder things together.
What is solder an alloy of and what are its uses?
135
# C2 - Chemical Resources
Mercury - a large scale use is in dentistry.
What is amalgam an alloy of and what are its uses?
136
# C2 - Chemical Resources
The name given to a family of alloys of nickel and titanium that have shape memory.
What is nitinol?
137
# C2 - Chemical Resources
Nitinol as the frames can be bent or sat on but still return to their normal shape.
What alloy can be used to make spectacles?
138
# C2 - Chemical Resources
iron + oxygen + water → hydrated iron (III) oxide
What is the word equation for the rusting of iron?
139
# C2 - Chemical Resources
If the water is acidic or salty.
What factors increase the reaction in the rusting of iron?
140
# C2 - Chemical Resources
It reacts very quickly with oxygen in the air to form aluminium oxide which becomes a protective layer stopping any more reaction taking place.
Why doesn't aluminium corrode?
141
# C2 - Chemical Resources
It has a lower density, making the car lighter and giving a better fuel economy. Also it corrodes less so will have a longer lifetime.
What are the advantages of aluminium over steel?
142
# C2 - Chemical Resources
It is much more expensive than iron or steel.
What is the disadvantage of using aluminium to make car bodies?
143
# C2 - Chemical Resources
Bodywork because it is strong and can be hammered into sheets and welded together.
What part of a car is steel good for?
144
# C2 - Chemical Resources
Parts of the engine - it is strong and low density so using it reduces the overall weight.
What part of a car is aluminium good for?
145
# C2 - Chemical Resources
Its transparency is used in the windscreens and windows.
What part of a car is glass good for?
146
# C2 - Chemical Resources
It is light and hard wearing, making it useful for internal coverings on doors and dashboards. Also as electrical insulators on wires.
What part of a car is plastic good for?
147
# C2 - Chemical Resources
Natural and synthetic are hard wearing and are used to cover the seats and floor.
What part of a car are fibres good for?
148
# C2 - Chemical Resources
85% of the materials in a car must be recyclable - rising to 95% by 2015
What is the European Law for recycling cars?
149
# C2 - Chemical Resources
All the non-metal parts must be separated before they are recycled.
What is the biggest problem with recycling cars?
150
# C2 - Chemical Resources
A combination of dyes that changes colour gradually as the pH changes.
Describe universal indicator...
151
# C2 - Chemical Resources
A sudden change indicator - it goes from colourless to pink when the pH rises above 8.
What is phenolphthalein an example of?
152
# C2 - Chemical Resources
A substance with a pH less than 7. Acids form H⁺ ions in water.
What is an acid?
153
# C2 - Chemical Resources
The concentration of H⁺ ions
What is pH a measure of?
154
# C2 - Chemical Resources
A substance with a pH over 7 and is soluble in water. They form OH⁻ ions in water.
What is a base?
155
# C2 - Chemical Resources
acid + base → salt + water
What is the word equation for neutralisation?
156
# C2 - Chemical Resources
H⁺ + OH⁻ ⇌ H₂O
What is the ionic equation for neutralisation?
157
# C2 - Chemical Resources
acid + metal oxide/hydroxide → salt + water
What are the word equations for metal oxides/hydroxides?
158
# C2 - Chemical Resources
→ salt + water + carbon dioxide
Complete: acid + carbonate…
159
# C2 - Chemical Resources
Acid + ammonia → ammonium salt
What is the word equation for acids and ammonia?
160
# C2 - Chemical Resources
Nitrogen - making proteins (amino acids) Phosphorous - respiration and growth Potassium - helps enzymes needed for photosynthesis and respiration.
What are the 3 essential elements in fertilisers and what are they needed for?
161
# C2 - Chemical Resources
dissolve in water
What must a fertiliser be able to do in order to be taken up by roots?
162
# C2 - Chemical Resources
Ammonium nitrate, ammonium sulfate, ammonium phosphate, potassium nitrate.
Give 4 examples of fertilisers…
163
# C2 - Chemical Resources
Eutrophication
What is the issue with fertilisers?
164
# C2 - Chemical Resources
Fertilisers run off into rivers and streams, increasing levels of nitrates and phosphates. Algae uses these nutrients to multiply rapidly - algael bloom, blocking off sunlight to plants meaning they die. Aerobic bacteria which eats dead plants multiply and use all oxygen, killing fish and insects.
What is eutrophication?
165
# C2 - Chemical Resources
Turns from yellow to red when alkali is neutralised (used in making ammonium nitrate)
What does methyl orange indicator do?
166
# C2 - Chemical Resources
Titration - methyl orange used. Nitric acid added to ammonia - goes from yellow to red. Evaporate solution until a little solution left - leave to crystallise. To get pure, note amount of acid needed and repeat but without indicator.
How is ammonium nitrate made?
167
# C2 - Chemical Resources
N₂ + 3H₂ ⇌ 2NH₃
What is the equation for the Haber process?
168
# C2 - Chemical Resources
Nitrogen - from the air (makes up 78% of air) Hydrogen - from cracking of oil fractions or natural gas
Where do the reactants for the Haber process come from?
169
# C2 - Chemical Resources
Pressure - High (200 atmospheres) Temperature - 450°C Catalyst - Iron
What are the industrial conditions for making ammonia?
170
# C2 - Chemical Resources
It favours the forward reaction and this high pressure increases the % yield of ammonia.
Why is the pressure high in the Haber Process?
171
# C2 - Chemical Resources
It favours the reverse reaction - so a high temperature decreases the % yield. 450 is optimum because it gives a fast reaction rate and a reasonable % yield (compromise).
Why is a high temperature used in the Haber process?
172
# C2 - Chemical Resources
It is recycled - so nothing is wasted.
What happens to unused hydrogen and nitrogen when making ammonia?
173
# C2 - Chemical Resources
It makes the reaction go faster which gets it to its equilibrium proportions more quickly - but doesn’t affect the position of equilibrium or % yield.
Why is an iron catalyst used in the Haber Process?
174
# C2 - Chemical Resources
Those that give the lowest production costs.
What are optimum conditions?
175
# C2 - Chemical Resources
Price of energy, cost of raw materials, labour costs/wages, plant costs (equipment), rate of production
What 5 factors affect production cost?
176
# C2 - Chemical Resources
Pumping hot water underground which dissolves the salt and the salt solution is forced to the surface because of the water pressure.
What is solution mining?
177
# C2 - Chemical Resources
The holes must be filled in otherwise it will cause subsidence where the land collapses and slides in to the hole.
What is the issue with salt mining?
178
# C2 - Chemical Resources
Hydrogen gas, chlorine gas and sodium hydroxide.
What is produced in the electrolysis of brine?
179
# C2 - Chemical Resources
Chlorine gas: 2Cl⁻ - 2e⁻ → Cl₂ OXIDATION
What is produced at the anode during the electrolysis of brine? (including half-equations)
180
# C2 - Chemical Resources
Hydrogen gas: 2H⁺ + 2e⁻ → H₂ REDUCTION
What is produced at the cathode during the electrolysis of brine? (including half-equations)
