C2 Flashcards
(63 cards)
0
Q
Why is it difficult to obtain information about the structure of the earth?
A
- Deepest mines and holes drilled only go a few kilometres into the earth into the thick crust
- Scientists rely on seismic waves caused by earthquakes to understand the structure of the earth
1
Q
Earth is made up of:
A
- thick, rocky crust
- mantle
- core (containing iron)
2
Q
What is the lithosphere?
A
• The relatively cold, rigid outer part of the earth, made of the crust and the top part of the mantle
3
Q
Lithosphere is cracked into several large interlocking pieces called..? Name the two different types.
A
• Tectonic plates
- oceanic plates (under oceans)
- continental plates (form continents)
4
Q
Why do plates sit on top of the mantle?
A
• They are less dense
5
Q
How fast do plates move? What can these movements cause?
A
• 2.5 cm a year
- Earthquakes
- Volcanoes
- Boundaries
6
Q
What causes plate movement?
A
- Deeper down the mantle becomes hot and fluid, which means it can flow
- There are convection currents, formed by heat released from radioactive decay in the core
- These convection currents cause magma (molten rock) to rise towards the surface at the boundaries between plates
- When this igneous rock solidifies it causes the movement of the plates
7
Q
Describe subduction.
A
- Oceanic crust has a higher density than continental crust
- Therefore, when they collide the oceanic crust will dip down and slide under the continental crust
- The oceanic plate is partially melted away as it goes under the continental plate
8
Q
Briefly describe Alfred Wegener’s theory on the Earth’s surface.
A
• 1914
He noted:
• Continents look like they would fit together like a jigsaw
• The Geology of Scotland and Canada was similar as was Africa and South America
• Similar species found on different sides of the Altantic e.g. Caribou in Canada and reindeer in Scandinavia
9
Q
How did Wegener’s theory come to be accepted?
A
- Initially scientists rejected his ideas
- Supported by studies in the 1960’s looking at new rock formed at boundaries
- The study showed: plates are moving apart and the age of the rock increases as you move away from the boundary
10
Q
What is a volcano?
A
- Volcanoes form at places where magma can find it’s way through weaknesses in the Earth’s crust
- This is often at plate boundaries or where the crust is thin
- The magma rises through the crust because it has a lower density than the crust
11
Q
Can geologists predict when an eruption will occur?
A
• Geologists are now begetter at predicting eruptions however they cannot be 100% accurate
12
Q
Why might someone choose to live near a volcano?
A
• The surrounding land is extremely fertile.
13
Q
What affects the size of crystal when lava cools and becomes igneous rock?
A
- Larger crystals = cools slowly -> silica-rich granite
* Small crystals = cools quickly -> iron-rich basalt
14
Q
What type of eruption does iron-rich basalt have?
A
- It’s quite runny
* Has fairly safe eruption
15
Q
What type of eruption does silica-rich rhyolite have?
A
- Thicker lava
- Violent and catastrophic eruptions
- Rhyolite lava makes pumice, volcanic ash and bombs
16
Q
What materials come from rocks called ores?
A
- Iron
* Aliminium
17
Q
What material is made by baking clay extracted from the Earth?
A
• Brick
18
Q
What material are made from sand?
A
- Glass
- Concrete
- Cement
19
Q
What rocks just need to be shaped before they can be used as building materials?
A
- Limestone (easiest to shape)
- Marble
- Granite (hardest to shape)
- Aggregates (gravel)
20
Q
Give example of sedimentary, metamorphic and igneous rock?
A
- Limestone –> sedimentary
- Marble –> metamorphic - made from limestone put under high pressure and heated making it harder
- Granite –> igneous
21
Q
What happens to calcium carbonate when heater? Give word and symbol equations.
A
• It breaks down into calcium oxide and carbon dioxide
Calcium carbonate –> calcium oxide + carbon dioxide
CaCO3(s) –> CaO(s) + CO2(g)
22
Q
What is a thermal decomposition reaction?
A
• One material breaks down when heated into two or kore new substances
23
Q
What two materials are heated together to make cement?
A
- Clay
* Limestone
24
What is a 'composite material'? +give an example.
```
• A composite material combines the best properties of each material
• Reinforced concrete
• Combines:
- strength and flexibility of steel bars
- hardness of concrete
```
25
What are the side affects of mining and quarrying on the surrounding area?
* be noisy and dusty
* take up land
* change the shape of the landscape
* increase local traffic
26
What does the acronym OIL RIG stand for?
Oxidation
Is
Loss
Reducation
Is
Gain
27
How is copper extracted? Give a word and symbol equation to support this.
* Copper is extracted from naturally occurring copper ore by heating it with carbon.
* copper oxide + carbon --> copper + carbon dioxide
* 2CuO(s) + C(s) --> 2Cu(s) + CO2
28
Why is the extraction of copper an expensive process? What alternatives are there?
* It requires a lot of energy
| * Recycling - this preserves the world's limited supply of copper ore and uses less energy
29
Why might it be difficult to recycle copper?
• If it has other metals stuck to it or mixed with it
30
What if the copper is very impure?
* It can be purified using electrolysis
| * However, it is an expensive process
31
What do electrolysis do?
• It uses an electric current to break down compounds into simpler substances
32
What is the solution in electrolysis called?
• The electrolyte
33
What is at the anode and cathode during the purification of copper though electrolysis?
• Electrodes are used to allow the electricity to flow through the electrolyte
• The anode - (positive electrode) is made of impure copper
Cu - 2e- --> Cu2+
• The cathode - (negative electrode) is made of pure copper
Cu2+ + 2e- --> Cu
34
What is an alloy? + Give examples.
* An alloy is a mixture of no metal with another element (usually another metal)
* Alloys improve the properties of a metal and make them more useful • Often they are harder and stronger than pure metal
* Bronze & steel
35
Give three examples of alloys and their use in everyday life.
* Amalgam - (made using mercury) is used for fillings in teeth
* Solder - (made of lead and tin) used to join wires
* Brass - (made of copper and zinc) is used indoor handles, coins and musical instruments
36
What is a smart alloy?
* Smart alloys can be bent and twiste
* They return to their original shape when heated (shape memory)
* Used for the frames of reading glasses
* Example - nitinol
37
What is used to make seatbelts and why?
* Nylon fibre
| * Strong & flexible
38
What is used to make windscreens and why?
* Glass
| * Transparency
39
What is used for the wiring in the engine and why?
* Copper
| * Good conductor
40
What is used for the trim and why?
* Plastic
| * Rigid & doesn't corrode
41
What is used for the body and why?
* Steel
| * Strong & malleable
42
What is used to make alloy wheels and why?
* Aliminium
| * Lightweight & doesn't corrode in moist conditions
43
What is steel an alloy of?
• Iron & Carbon
44
What are the advantages do using aluminium to make a car? however why isn't it widely used?
* Longer lifetimes as it won't corrode
* Aluminium is less dense than steel, the car will be lighter so it will have better fuel economy
* It's far more expensive
45
What does rusting require?
* Iron
* Water
* Air (oxygen)
46
What speeds up rusting?
* Salty water
| * Acid rain
47
Why doesn't aluminium react and corrode in air and water?
* It quickly forms a protective layer of aluminium oxide
* This layer stops any more air and water coming into contact with the metal
* This protection will not flake off
48
What is the word equation for rusting?
iron + oxygen + water ---> hydrated iron(III) oxide
49
What is the regulation surrounding how much of a car must be recycled?
* 2006 - 85% of a car must be recyclable
| * 2015 - 95% of a car must be recyclable
50
Disadvantage of recycling.
• Tricky & time consuming
51
Advantages of recycling.
* less quarrying required
* less energy used to extract them from ores
* the limited ores reserves will last longer (preserving natural resources)
* disposal problems are reduces
* reduces need for crude oil
* some materials cause pollution if put into landfill, so it protects the environment
52
What is ammonia made from?
| What can ammonia be used to make?
* Ammonia (alkaline gas) is made from nitrogen and hydrogen
* Ammonia is used to make nitric and and fertilisers - cheap fertilisers are vital to ensure enough food is grown for a growing world population
53
What type of reaction does the Haber process have?
* reversible
| * e.g. Nitrogen and hydrogen can form ammonia, and ammonia can decompose to make hydrogen and nitrogen
54
Where are nitrogen and hydrogen used in the Haber process sourced from?
* Nitrogen --> the air
| * Hydrogen ---> from natural gas or cracking crude oil
55
Give the word and symbol equation for the reaction between nitrogen and hydrogen (the Haber process)
Nitrogen + hydrogen ammonia
| N2(g) + 3H2(g) 2NH3(g)
56
Why aren't optimum conditions used in the Haber process? What is used instead?
* Too expensive to maintain so a compromise is reached
* The nitrogen and hydrogen mixture is under high pressure of 200 atmospheres
* The gases are passed over an iron catalyst at 450°
57
What percentage of the reactance gases make ammonia (the Haber process)? That happens the the rest?
* 15%
* The rest are recycled
* Ammonia is cooled, condensed and pumped of as a liquid
58
What factors affect the cost of making a new substance?
* Energy price - gas & electricity
* Labour cost - wages/training for staff
* Time taken to to make the substance - cost of catalyst
* Cost of starting materials - reactancta
* Cost of equipment needed (plant and machinery)
59
How does the temperature, pressure and presence of a catalyst affect the percentage yield of ammonia?
* A low temperature increases yield but the reaction is too slow
* A high pressure increases yield but becomes more expensive as yield increases
* A catalyst increases the rate of reaction but doesn't change the percentage yield
60
The pH scale goes from red to purple, what does this represent in terms of strength of acid or alkaline?
* 0 = Red = Strongly Acid
* 7 = Green = Neutral
* 14 = 14 = Strongly Alkaline
61
What needs to be added to acids to neutralise them?
| What is the word equation for this neutralisation reaction?
* Bases such as metal oxides and metal hydroxides
* When they are added to acids in the correct amounts, they cancel each other out
* The resulting solution has a pH of 7 (neutral)
* acid + base --> salt + water
62
What happens when an acid is neutralised by a carbonate?
• They produce salt, water and carbon dioxide gas
• For example:
acid + carbonate ---> salt + water + carbon dioxide
