C2 Flashcards
(170 cards)
1
Q
What is the crust?
A
The earths thin outer layer of solid rock
2
Q
What is the average depth of the core?
A
20km
3
Q
What is the lithosphere?
A
It includes the crust and the upper part of the mantle, it is made up of a jigsaw of ‘tectonic plates’
4
Q
Give two properties of the lithosphere
A
It is relatively cold and rigid
It is over 100km thick in places
5
Q
What is the mantle?
A
The solid section between the crust and the core
6
Q
What happens as you get closer to the mantle?
A
The temperature increases
7
Q
As the temperature increases what happens to the mantle?
A
It becomes less rigid
It can flow very slowly
It behaves like a semi-liquid
8
Q
Give a property of the core
A
It is just over half the Earth’s radius
9
Q
Give a property of the inner core
A
It is a solid
10
Q
Give a property of the outer core
A
It is a liquid
11
Q
What are convection currents?
A
The heat from the core rises up and causes the magma to go towards the crust, as the cool magma from higher up falls closer to the core. This causes currents in the magma to move the tectonic plates of the lithosphere to move.
12
Q
Why do the tectonic plates float on the mantle?
A
Because they are less dense than the mantle
13
Q
What happens to the continents when the plates move?
A
The continents move too
14
Q
How much do the plates move each year?
A
2.5 cm
15
Q
What happens when the plates meet?
A
Volcanoes and earthquakes
16
Q
Why can’t you get to the inner structure of the earth directly?
A
Because the crust is too thick to drill through
17
Q
What waves to scientists use to study the Earth’s structure?
A
Seismic waves (shock waves)
18
Q
How can seismic waves be produced?
A
Earthquakes
Big man-made explosion at the earth’s surface
19
Q
How can scientists draw conclusions about the structure of the earth?
A
By measuring the time that it takes for seismic waves to travel through the earth, and finding out where they are detected.
20
Q
What are the two types of seismic waves?
A
S-waves
P-waves
21
Q
What can P-waves travel through?
A
Solids and liquids
22
Q
What can S-waves travel through?
A
Solids only
23
Q
S-waves can travel through the mantle which means that it is _____.
A
Solid
24
Q
S-waves are not detected in the core’s shadow, so the outer core must be _____.
A
Liquid
25
P-waves travel faster through the middle of the core, which suggests that the inner core is _____.
Solid
26
When has the idea that they Earth's surface is made up of moving plates of rock been around from?
The early twentieth century
27
Fossils of similar plants and animals have been found on opposite sides of the Atlantic ocean, why did most people in the past think this was?
They thought that the continents had been linked by 'land bridges' which had sunk or been covered by water as the earth cooled.
28
What things puzzled people, regarding the Earth's structure?
Why the coastlines of Africa and South America fit together
| Why there are fossils of sea creatures in the Alps
29
In 1914 who hypothesised that Africa and South America had once been one continent?
Alfred Wegener
30
What evidence did Alfred Wegener find to back up his hypothesis?
There were matching layers in the rocks on different continents
There were similar earthworms living in both South Africa and South America
31
What did Wegener's theory of 'continental drift' suppose?
It supposed that about 300 million years ago there had been one 'supercontinent' - which he called Pangaea
According to Wegener, Pangaea broke into smaller chunks and these chunks (our modern day continents) are slowly drifting apart.
32
Why wasn't Wegener's theory accepted at first?
It was a big change and the reaction from other scientists was hostile
His explanation of HOW the 'drifting' happened wasn't convincing
The movement wasn't detectable
He claimed the movement could be caused by tidal forces and the earth's rotation
But other geologists proved the later was impossible
33
In what decade did scientists investigate the Mid-Atlantic ridge and why was this significant?
1960s
They found evidence that magma rises up through the sea floor, solidifies and forms underwater mountains.
This suggested that the sea floor was spreading at about 10cm per year and thus supported Wegener's theory
34
Where did even better evidence that the continents were moving apart come from?
The magnetic orientation of the rocks.
35
Give evidence for the magnetic field of the Earth expanding and swapping directions
The rock on either side of the ridge had bands of alternative magnetic polarity.
These are symmetrical about the ridge.
36
How do volcanoes occur?
```
Molten rocks (magma) from the mantle emerges through the Earth's crust. Magma rises up (through the crust) and 'boils over' where it can erupt.
This can sometimes be quite violent if the pressure is released suddenly.
```
37
What is the difference between magma and lava?
Molten rock below the earths surface is called magma
| When it erupts from a volcano, it's called lava.
38
Which is denser? The crust on the ocean floor or the crust below the continents?
The crust on the ocean floor
39
What is subduction?
When two tectonic plates collide, a dense oceanic plate will be forced underneath a less dense continental plate.1
40
Finish the sentence:
Oceanic crust tends to be ____ at the _____ of a tectonic plate - so the edges _____ easily, ______ the oceanic plate _____
```
cooler
edges
sink
pulling
down
```
41
What happens to the oceanic crust in subduction?
It is forced down, melts and starts to rise. When this molten rock finds its way to the surface, volcanoes form.
42
What is igneous rock?
It is made when any sort of molten rock cools down and solidifies.
43
What does the type of igneous rock depend on?
How quickly the magma cools
| The composition of the magma
44
Is a volcano fairly safe or not if the magma produces iron-rich basalt?
Yes, the lava from this eruption is runny meaning it is fairly safe
45
Is a volcano fairly safe or not if the magma produces silica-rich rhyolite?
No, this means that they eruption is explosive. It produces thick lava which can be violently blown out of the top of the volcano.
46
Give an example of a way that scientists can detect if a volcano is going to erupt
If there is magma movement below the ground, near to a volcano
47
What are the three different types of rock?
Sedimentary
Metamorphic
Igneous
48
How are sedimentary rocks formed?
From layers of sediment laid down in lakes or seas
| Over millions of years the layers get buried under more layers and the weight pressing down squeezes out the water.
49
What type of rock is limestone?
Sedimentary
50
What is limestone mostly formed from?
Seashells, calcium carbonate.
51
What happens to limestone when it is heated?
It thermally decomposes to make calcium oxide and carbon dioxide
52
Write a symbol equation for the thermal decomposition of limestone
CaCO3 (s) ---> CaO (s) + CO2 (g)
53
How are metamorphic rocks formed?
They are formed by the action of heat and pressure on sedimentary (or even igneous) rocks over long periods of time.
54
Finish this sentence:
| As long as the rocks don't actually ___ they're classed as __________ rocks.
melt
| metamorphic
55
What happens if metamorphic rocks melt?
They turn into magma and are gone. They may eventually re-surface as igneous rocks.
56
What type of rock is marble?
It is a metamorphic rock formed from limestone
57
Out of marble, limestone and granite, label them in order of hardness rating from most hard to least hard.
Granite
Marble
Limestone
58
How does limestone turn into marble?
They are made of the same chemicals
Very high temperatures and pressures break down the limestone and it reforms as small crystals
This gives marble a more even texture and makes it much harder.
59
How are igneous rocks formed?
When magma cools
60
Why are igneous rocks very hard?
Because they contain various different minerals in randomly arranged interlocking crystals.
61
What is granite ideal for?
Steps and buildings
62
What are ores?
Minerals we can get useful materials from
63
Give two examples of construction materials that can be extracted from ores
Aluminium and iron
64
How is glass made?
By heating up limestone (calcium carbonate), sand (silicon dioxide) and soda (sodium carbonate) until it melts.
65
What is clay?
It is a mineral formed from weathered and decomposed rock.
66
How is clay made into bricks?
Dug from the ground, soft
Moulded into shape
Hardened by firing at very high temperatures
67
What does clay contain?
Aluminium and silicates
68
How is cement made?
Powdered clay and powdered limestone are roasted in a roasting kiln to make a complex mixture of calcium and aluminium and silicates
69
What causes cement to gradually set?
When it is mixed with water. (it causes a slow chemical reaction to take place)
70
How is concrete made?
Cement mixed with sand, aggregate and water
71
What is reinforced concrete?
It is a 'composite material'
A combination of concrete and a solid steel support.
This combines the hardness of concrete with the flexibility and the strength of steel
72
Give some disadvantages of quarrying
```
Uses up land
Destroys habitats
Noise pollution
Produces dust
People drown in disused sites made into very very deep lakes
```
73
What does electrolysis mean?
Splitting up with electricity
74
Name, out of the anode and the cathode, which is positive and which one is negative
Positive - anode
| Negative - cathode
75
What is the liquid called that electrolysis takes place in? And what does it contain?
Electrolyte
| It contains free ions dissolved in water.
76
Which electrolyte is used in purifying copper?
Copper(II) sulphate solution
77
Explain the process of purifying copper through the electrical supply
1) The electrical supply pulls electrons off copper atoms at the anode, causing them to go into the solution as Cu2+ ions
2) It then offers electrons at the cathode to nearby CU2+ ions to turn them back into copper atoms
3) The impurities are dropped at the anode as a sludge, whilst pure copper atoms bond to the cathode
78
Which piece of copper is put at the anode?
The impure copper
79
Which piece of copper is put at the cathode?
The pure copper
80
Give a symbol equation of the reaction at the cathode
Cu2+(aq) + 2e- ---> Cu(s)
81
Give a symbol equation of the reaction at the anode
Cu(s) ---> Cu2+(aq) 2e-
82
What is reduction?
The gain of electrons
83
Where does reduction happen?
At the cathode
84
What is oxidation?
The loss of electrons
85
Where does oxidation happen?
At the anode
86
Give some advantages of recycling copper
It is cheaper
| Only uses 15% of the energy used to mine and extract the same amount
87
What is an alloy?
A mix of two or more different metals
| They can also be a mixture of a metal and a non-metal
88
What is steel an alloy of?
Iron and Carbon
89
In what ways is steel better than iron?
It is harder
Stronger (as long as the amount of carbon does not get larger than about 1%)
Doesn't corrode as easily
90
Name 5 things that are made from steel
```
Bridges
Engine parts
Cutlery
Washing machines
Saucepans
Ships
Grinders
Drill bits
Cars
```
91
What is brass an alloy of and what is it used for?
Copper and zinc
| Musical instruments, screws, springs, doorknobs
92
What is bronze an alloy of and what is it used for?
Copper and tin
| Springs, motor bearings, bells
93
What is solder an alloy of and what is it used for?
Lead and tin
| Soldering things together
94
What does amalgam contain and what is it used for?
Mercury
| Used in dentistry for filling teeth
95
What is special about nitinol?
It has shape memory
96
What is a practical use for nitinol?
Glasses rims
97
When does rusting of iron happen?
When the iron is in contact with oxygen and water
98
What kind of reaction takes place when iron corrodes?
An oxidation reaction
99
What is the word equation of rust?
iron + oxygen + water ---> hydrated iron(III) oxide
100
When will rusting occur a lot quicker?
If the water is salty or acidic
101
Why doesn't aluminium appear to corrode as much?
Aluminium is so much more reactive so reacts with all the oxygen it can when it is available, this forms aluminium oxide. A protective layer of aluminium oxide sticks to the aluminium below and stops any further reaction taking place. The oxide isn't crumbly and flaky like rust, so it wont fall off.
102
What two big advantages does Aluminium have over steel?
It has a much lower density, so the car body of an aluminium car will be lighter then the same car made of steel. This gives it much better fuel economy which saves fuel resources.
A car body made with aluminium corrodes less and so it will have a longer lifetime.
103
What is a massive disadvantage of aluminium?
It is expensive
104
Give an example of 5 materials and their uses in a car
Steel - strong, hammered into sheets and welded together, good for body work
Aluminium - strong, low density, used for engine parts to reduce weight
Glass - windscreens and windows
Plastics - light and hardwearing, internal coverings for doors, dashboards etc. Electrical insulators used for covering electrical wires
Fibres - natural, synthetic, hard-wearing, used to cover seats and floor
105
What is a problem with recycling all the non-metal parts of a car?
They have to separated before they can be recycled
106
On the pH scale, which side is acid and which side is alkali?
1-6 acid
| 8-14 alkali
107
What is an indicator?
A dye that changes colour
| The dye changes colour depending on the pH of a substance
108
What is a universal indicator?
A combination of dyes what changes colour gradually as the pH changes
109
What substance would be a pH of 7?
Pure water
110
Give a definition for an acid
An acid is a substance with a pH of less than 7
111
What do acids form in water?
H+ ions
112
What is the concentration of an acid determined by?
The concentration of the H+ ions
113
Give a definition for a base
A substance with a pH of greater than 7
114
Give a definition for an alkali
It is a base that is soluble in water
115
What do alkalis form in water?
OH- ions
116
What is the reaction between acids and bases called?
Neutralisation
117
What is the word equation for a neutralisation reaction?
acid + base ---> salt + water
118
What is the symbol equation for a neutralisation reaction?
H+ + OH- H2O
119
What are metal oxides and metal hydroxides?
Bases
120
Acid + metal oxide = ______________
Salt + Water
121
Acid + metal hydroxide = _______________
Salt + water
122
Hydrochloric acid + copper oxide = ___________
Copper chloride + water
123
What do acids and carbonates produce?
Carbon dioxide
124
Acid + Carbonate ---> ____ + ________ + _________ ________
Salt + Water + Carbon doxide
125
What do acids and ammonia produce?
Ammonium salts
126
Acid + Ammonia ---> ________ ______
Ammonium salt
127
What do fertilisers provide plants with?
Essential elements for growth
128
What are the three main essential elements on fertilisers?
Nitrogen, phosphorous and potassium
129
What happens if plants don't get enough of the essential elements?
Their growth and life processes are affected
130
What do fertilisers increase?
The crop yield
131
What is a key ingredient in many fertilisers?
Ammonia
132
How can you make ammonium sulphate?
By neutralising sulphuric acid with ammonia
133
How can you make ammonium phosphate?
By neutralising phosphoric acid and ammonia
134
How can you make potassium nitrate?
By neutralising nitric acid with potassium hydroxide
135
What is a problem with using too many fertilisers?
Too many fertilisers means we are at a higher risk of polluting our water supplies, this causes eutrophication
136
In 6 points, explain eutrophication
1. Fertiliser on fields runs off the fields into rivers and streams
2. The level of nitrates and phosphates in the water increases
3. Algae living in the river water uses the nutrients and multiplies rapidly causing an algae bloom (carpet of algae on the surface of the river)
4. Blocks off the light to the river plants below, plants cannot photosynthesise, have no food and die
5. Aerobic bacteria feed off the dead plants and start to multiply, they use up all the oxygen in the water and as a result everything in the river dies
6. This process is called eutrophication and means 'too much of a good thing'
137
What is the most commonly used fertiliser?
Ammonium nitrate
138
Explain an experiment that you can do to create your own fertiliser
1. Set up apparatus, a glass on the table, with a burette held in place with a clamp above it
2. Put ammonia solution in the glass then add a few drops of methyl orange indicator, this will turn it yellow
3. Fill the burette with nitric acid solution then slowly add the nitric acid from the burette into the ammonia until the yellow colour JUST changes to red.
4. Gently swirl the flask as you add the acid.
5. Go slowly when you think the acid is almost neutralised.
6. You have ammonium nitrate solution.
139
How do you make ammonium nitrate crystals?
Get ammonium nitrate solution and evaporate the liquid until only a little bit is left. Leave it to crystallise.
140
What is the name for the method used to make fertilisers?
Titration
141
What does 100% yield mean?
That you got all of the product you expected to get
142
What is the predicted yield of a reaction?
The amount of product that you'd get if all the reactant was converted into product
143
What type of reaction is the Haber Process?
A reversible one
144
What is the symbol equation for the Haber Process?
N2 + 3H2 2NH3
145
Where does the nitrogen come from in the Haber Process?
The air (which is 78% nitrogen)
146
Where does the hydrogen come from in the Haber Process?
The cracking of oil fractions or natural gas
147
What happens to the N2 and the H2 that doesn't always react in the Haber Process?
It is recycled so that none is wasted
148
What are the industrial conditions for the Haber Process?
Pressure : High (200 atmospheres)
Temperature : 450 degrees Celsius
Catalyst : Iron
149
Out of the forward reaction and the backwards reaction, which one is favoured when you increase the pressure in the Haber Process?
The forward reaction
150
Out of the forward reaction and the backwards reaction, which one is favoured when you increase the temperature in the Haber Process?
The backwards reaction
151
Give an advantage and a disadvantage of using a lower temperature in the Haber Process
Advantage : Higher percentage yield
| Disadvantage : Slower reaction rate
152
Why is the catalyst important in the Haber Process?
It makes the reaction go faster without having an effect on the final outcome
It gets it to the equilibrium proportions more quickly
Without the catalyst the temperature would have to be raised even further
153
What 5 things does production cost depend on?
```
Price of energy
Cost of raw materials
Labour cost (wages)
Plant costs (equipment)
Rate of production
```
154
Why are optimum conditions chosen?
To give the lowest cost
155
What is the chemical formula for salt?
Sodium Chloride
| NaCl
156
Where is salt mined from?
Underneath Cheshire
157
How can salt be mined?
Drilling into the ground and digging it out
| It can also be done by pumping hot water underground
158
What is solution mining?
Where hot water is pumped underground and the salt from under the ground dissolves into the salt solution. This is forced to the surface by the pressure of the water
159
What is subsidence?
When land collapses and slides into the holes in the ground left from salt mining
160
What can salt be used for?
To stop ice forming on roads
Enhancing the flavour of food
Making chemicals
161
What is the chlor-alkali process?
Where salt is electrolysed for use in chemicals
162
What does the Electrolysis of brine create?
Hydrogen, Chlorine, and Sodium Hydroxide (NaOH)
163
During the electrolysis of Brine what is created at the cathode?
Hydrogen Gas
164
During the electrolysis of Brine what is created at the anode?
Chlorine gas
165
Give a symbol equation of what happens at the cathode during the electrolysis of brine
2H+ + 2e- ---> H2
166
Give a symbol equation of what happens at the anode during the electrolysis of brine
2Cl- - 2e- ---> Cl2
167
What is oxidation?
The loss of electrons
168
What is reduction?
The gain of electrons
169
What type of reaction is the reaction at the anode during the electrolysis of brine?
And oxidation reaction
170
Why type of reaction is the reaction at the cathode during the electrolysis of brine?
The reduction reaction
