C6.1: Improving Processes And Products Flashcards
1
Q
What are the 3 essential elements needed by plants?
A
Nitrogen
Phosphorus
Potassium
2
Q
What happens to plants if they are not supplied with the essential elements?
A
Plants do not grow as well - show signs of mineral deficiency
3
Q
What are the typical symptoms of deficiency when there is a lack of potassium?
A
Poor fruit growth
Discoloured leaves
4
Q
What are the typical symptoms of deficiency when there is a lack of phosphorus?
A
Poor root growth
Discoloured leaves
5
Q
What are the typical symptoms of deficiency when there is a lack of Nitrogen?
A
Poor growth
Yellow leaves
6
Q
What are fertilisers?
A
Substances that replace the elements made by plants as they grow
7
Q
In which state must fertilisers be in
A
Water-soluble form
Allows plant roots to absorb it
8
Q
What does water-soluble mean?
A
Something that can be easily dissolved in water
9
Q
Why are ions water soluble?
A
Water is a polar molecule
Positive and negative charges of the water pull apart positive and negative ions
Surrounds the split ions with water molecules, keeping them dissolved
10
Q
What is a polar molecule?
A
A molecule with an uneven distribution of charge
11
Q
What is the ion form of nitrogen?
A
Nitrate ions
Ammonium ions
12
Q
What is the formula for nitrate ions
A
NO3-
13
Q
What is the formula for ammonium ions
A
NH4+
14
Q
What is the ion form of phosphorus?
A
Phosphate ions
PO4 3-
15
Q
What is the ion form of potassium?
A
Potassium ions
K+
16
Q
What are NPK fertilisers?
A
Fertilisers that provide nitrogen, phosphorus and potassium in water soluble compounds
17
Q
What is the Haber process?
A
A method used to produce ammonia from nitrogen and hydrogen
18
Q
What is the haber process formula?
A
N2 (g) + 3H2 (g) <==> 2NH3 (g)
19
Q
What is ammonia used for?
A
To make fertilisers
20
Q
What are the raw materials for the Haber process?
A
Air
Natural gas
Steam
21
Q
How do you obtain nitrogen?
A
Comes from air
78% nitrogen
22
Q
How do you obtain hydrogen?
A
Obtained from hydrocarbons such as methane
23
Q
Why is the Haber Process important?
A
Ammonia produced - used to make nitrogen based fertilisers
24
Q
What type of reaction is the Haber Process?
A
Exothermic
Reversible
25
What does an exothermic reaction mean?
Produces heat
26
What does an endothermic reaction mean?
Takes in heat
27
Why does the haber process have a very high yield?
It recyles back any unreacted raw materials
Reversible reaction
28
What temp does the haber process use?
450 degrees C
29
Why does the haber process use 450 degrees C?
Forward reaction is exothermic, so reaction should be done at low temp for high yield
Reaction will be faster at higher temps, more collisions due to more kinetic energy
Generating high temps expensive
450 used as compromise
30
What pressure is used in the Haber Process?
200 atmospheres
31
Why does the Haber Process use 200 atm?
High pressure needed to favour forward reaction
Particles collide more frequently
BUT
High pressure is expensive and dangerous
200 is a compromise
32
What is the approximate yield of the Haber Process?
Around 98%
33
The haber process considers something else other than temp and pressure. What?
Iron Catalyst
34
What does an iron catalyst do in the Haber Process?
Speeds up the forward and reverse reaction
No effect on equilibrium
35
What is a batch process?
Making small amounts of products
36
What are continuous processes?
Large industrial amounts
37
What must be done to the raw materials before or after making fertilisers?
Must be purified
38
How is the rate of production in batch vs continous processes?
Batch: low
Continuous: high
39
How is the cost of equipment in batch vs continous processes?
Batch: low
Continuous: high
40
How is the number of workers in batch vs continous processes?
Batch: large
Continuous: small
41
How is the shut down periods in batch vs continous processes?
Batch: frequent
Continuous: rare
42
How is the ease of automating in batch vs continous processes?
Batch: hard
Continuous: easy
43
What are 2 hazards of making fertiliser compounds in a lab?
Release of toxic fumes
Exposure to corrosive chemicals
44
What is the contact process?
An industrial process used to make sulfuric acid
45
What materials are needed for the contact process?
Sulfur
Oxygen
Water
46
What is stage 1 of the contact process?
And include chemical formula
Sulfur burns in oxygen forming sulfur dioxide
S (s) + O2 (g) —> SO2 (g)
47
Is the contact process exothermic or endothermic?
Exothermic
48
What is stage 2 of the contact process?
And include chemical formula
Sulfur dioxide reacts with oxygen to form sulfur trioxide
2SO2 (g) + O2 (g) <==> 2SO3 (g)
49
What are the conditions for stage 2 of the contact process?
450 degrees C
2 atm
Vanadium pentoxide catalyst
50
What is the yield of stage 2 of the contact process?
About 96%
51
What is stage 3 of the contact process?
And include chemical formula
Sulfur trioxide is converted into sulfuric acid
H2O (l) + SO3 (g) —> H2SO4 (aq)
52
Why is a temp of 450 degrees C used in the contact process?
High temp increase the rate of reaction
High temps expensive and decrease the yield as forward reaction is exothermic
The catalyst only works at a temp above 380 degrees C
53
Why is a pressure of 2 atm used during the contact process?
High pressure inc rate of reaction
High pressure is expensive
Compromise
54
Why is vanadium oxide used as a catalyst in the contact process?
Used to inc rate of reaction
No effect on yield
55
What is an ore?
A rock that contains a metal that is enough to be economically viable enough to extract
56
What are the extraction methods of metals?
Electrolysis
Heat with carbon
57
How do we know which method of extraction to use?
Depends on reactivity series
Carbon only works when metals less reactive than carbon
58
What happens to ores after extracting?
Extracted by mining
Processed to separate the metal
59
Pros of using electrolysis for metal extraction?
Can extract all metals
60
Cons of using electrolysis for metal extraction?
Expensive
61
How is copper extracted from its ore? What type of reaction
Redox reaction
Roasted in air to produce copper oxide and sulfur dioxide
Copper oxide heated with carbon to produce carbon dioxide and copper
62
What is a blast furnace?
Used to extract iron from its ore at a high temp using carbon
63
How is iron extracted from its ore?
Blast furnace
Raw materials: iron ore from haematite, coke, limestone for purifying
64
What is stage 1 of producing liquid iron from haematite?
Coke burns in hot air making carbon dioxide
C (s) + O2 (g) —> CO2 (g)
65
What is stage 2 of producing liquid iron from haematite?
Coke reduces the carbon dioxide making carbon monoxide
C (s) + CO2 (g) —> 2CO (g)
66
What is stage 3 of producing liquid iron from haematite?
Carbon monoxide reduces Iron (III) oxide to iron at around 1500 degrees C
Liquid iron is formed but there are a lot of impurities which need to be removed
67
What is stage 1 of removing impurities from liquid iron using limestone?
Calcium carbonate decomposes in high temps
CaCO3 (s) —> CaO (s) + CO2 (g)
68
What is stage 2 of removing impurities from liquid iron using limestone?
Calcium oxide reacts with silica to form calcium silicate
Called a slag
69
What is a slag?
Calcium silicate
70
Why is a slag important for removing impurities?
Floating on top of melted metal and makes a layer
Slag can be scooped off and makes metal clean
71
What is the limestone formula?
CaCO3
72
What is coke?
Purified coal used as fuel
Formula: C (s)
73
What is the aluminium ore called?
Bauxite
74
By which method is aluminium extracted?
Electrolysis - costly
75
Aluminium oxide has a melting point of 2072 degrees but thats too expensive to heat. How do we get around it?
Molten cryolite is dissolved with aluminium oxdiee which allows electrolysis to happen at 950 degrees C
76
What is used as the cathode in extracting aluminium electrolysis?
Graphite lining
77
What is used as the anode in extracting aluminium electrolysis?
Large graphite blocks
78
Where is the molten mixture of aluminium oxide and cryolite contained in during the electrolysis of aluminium extraction?
A huge electrolysis cell that is made from steel and lined with graphite
79
What is produced at the cathode when extracting aluminium?
Aluminium
80
What is produced at the anode when extracting aluminium?
Oxygem
Reacts with graphite anodes
Making carbon dioxide
81
Why do the graphite blocks need to be replaced in extracting aluminium electrolysis?
The carbon dioxide formed at the anode wears tem away overtime
82
What half equation occurs at the cathode in extracting aluminium electrolysis?
Al3+ + 3e- —> Al
83
What half equation occurs at the anode in extracting aluminium electrolysis?
2O2- —> O2 + 4e-
84
What is bioleaching?
Using bacteria to extract copper by wearing the rock away
85
What is phytoextraction?
Growing plants in soil with metal compounds, to be extracted from the plant later
86
Pros of bioleaching
Low grade copper ore can be used
Cheap
87
Cons of bioleaching
Slow
Toxic substances
88
Pros of phytoextraction
Cheaper
Less waste
Carbon neutral activity
89
Cons of phytoextraction
Slow
Crops need replanting and harvesting for years
90
What is the process of phytoextraction?
Plants are given a complexing agent to help them absorb mineral ions better
Plants grow, harvested, burned
Ash has a high conc of metal
Metal extracted from ash
91
What is an alloy?
A mixture of 2 or more elements, where at least 1 is a metal
92
What is tensile strength?
The resistance of a material to breaking under tension
93
What is ductility?
Ability to be drawn into wires
94
Why is an alloy stronger than a pure metal?
Alloys have different sized atoms so when they mix, the smaller atoms distort the layers and make it difficult for them to slide over each other - making them stronger
95
What are steel alloys made from and what are their properties?
Iron, carbon and other metals
High strength
Ductile
96
What does it mean when something is corrosive?
Tending to cause corrosion, wearing away, eroding
97
What are solder alloys made from? Properties?
Tin and lead
Strong
Low melting point
Electrical/thermal conductivity
98
What are brass alloys made from and what are their properties?
Made of copper and zinc
Resists corrosion
Strength
High electrical/thermal conductivity
Good malleability and ductility
99
What are bronze alloys made from? Properties?
Copper and tin
Hardness
Ductility
Flexibility
100
What are duralumin alloys made from? Properties?
Consists of aluminium, containing 4% copper
Soft
Ductile
Light weight
101
What can solder alloys be used for?
Joining copper pipes and electrical components
102
What can steel alloys be used for?
Pipelines
Building beams
103
What can bronze alloys be used for?
Propellers for ships
Bells
104
What can duralumin alloys be used for?
Aircraft parts
105
What can brass alloys be used for?
Coins
Musical instrument
106
What makes a metal strong?
If the layers are hard to slide over each other, the stronger the metal
107
Why is steel good for making car body parts?
Because it is easily pressed into shape, malleable
108
What is corrosion?
The destruction of materials by chemical reactions with substances in the environment
109
What is the word equation for rusting?
Iron + oxygen + water -> hydrated iron (III) oxide
110
What is the balanced symbol equation for rusting?
4Fe + 3O2 + 6H2O —> 2Fe2O3 . 3H2O (s)
111
Which physical barriers can be used to prevent oxygen and water needed for rust?
Painting
Oiling and greasing
Coating with plastic
112
How can electroplating be used to prevent rust?
Putting a thin layer of metal on the object
113
What is at the anode when electroplating an object?
The plating metal
114
What is at the cathode when electroplating an object?
Iron or steel object
115
What is the electrolyte when electroplating an object?
Contains ions of the plating metal
116
How can sacrificial protection be used to prevent rust?
A corrosion prevention where a more reactive metal is attached to a less reactive metal to prevent the less reactive metal from corroding as the more reactive metal corrodes in its place
117
How can galvanising be used to prevent rust?
Zinc layer stops oxygen and water reaching the iron
Zinc is more reactive than iron so it acts as a sacrifice
This works even if the zinc is scratched
118
What is the appearance like of glass ceramics?
Transparent
119
What is the appearance like of clay ceramics?
Opaque
120
What is the appearance like of metals?
Shiny
121
What is the melting point like of glass ceramics?
High
122
What is the melting point like of clay ceramics?
High
123
What is the melting point like of metals?
High
124
Malleable or brittle of glass ceramics?
Brittle
125
Malleable or brittle of clay ceramics?
Brittle
126
Malleable or brittle of metals?
Malleable
127
How is the ability to conduct electricity and heat of glass ceramics?
Poor
128
How is the ability to conduct electricity and heat of clay ceramics?
Poor
129
How is the ability to conduct electricity and heat of metals?
Good
130
How are glass ceramics made?
Made by melting sand and allowing the molten to cool and solidify
131
How are clay ceramics made?
Brick, china, porcelain
Heating clay to high temps which causes crystals to form and join together. Often coated with a glaze
132
What is the conductivity like of polymers?
Poor
133
What is the properties of polymers?
Tough
Flexible
BUT SOMETIMES
Hard
Flexible
134
Properties of poly(ethene)
Flexible
Cheap
Can be made into thin films
135
Properties of poly(propene)
Flexible
Strong
Resists shattering
136
Properties of poly(chloroethene)
Tough
Electrical insulator
Can be made hard or flexible
137
Properties of poly(tetrafluoroethene)
Slippery
Chemically unreactive
138
Uses of poly(ethene)
Carrier bags
Shmpoo bottles
Food wrap
139
Uses of poly(propene)
Buckets
Bowls
Crates
Ropes
Carpets
140
Uses of poly(chloroethene)
Insulation for electrical wires
Windows
Gutters
Pipes
141
Uses of poly(tetrafluoroethene)
Non stick coatings for pans
Containers for laboratory substances
142
What is a composite material?
Made from 2 or more diferent materials combined to improve properties
143
What are the 2 components of most composite materials?
Reinforcement
Matrix
144
What is the role of reinforcement in composite materials?
Gives strength to the composite material
145
What is the role of the matrix in composite materials?
Holds the reinforcement together and binds it
