C3 Flashcards
(103 cards)
1
Q
What do geologists do?
A
They study rocks to see how the Earth’s surface has changed. They look at how rocks form, how they change, and when changes happen.
2
Q
How do geological changes occur?
A
By slow movements of TECTONIC PLATES.
3
Q
How can plates move?
A
By sliding past each other, colliding or pulling apart.
4
Q
What do plate collisions build?
A
Mountain ranges, which occur over time.
5
Q
What can geologists explain?
A
Most of the past history of the Earth by processes they can observe today.
6
Q
6000 million years ago, what happened to the region of Britain?
A
England and Wales were separated from Scotland by an ocean, and both were near the South Pole.
7
Q
Gradually, what did different continents do?
A
They drifted and crashed together to form a SUPERCONTINENT called Pangea.
8
Q
In terms of rocks, what is Britain made of?
A
Britain is made from rocks from DIFFERENT ANCIENT CONTINENTS.
9
Q
Where was Britain originally?
A
Britain was near to the equator with a warmer climate. Different climates existed in Britain.
10
Q
How are IGNEOUS ROCKS formed?
A
When volcanic lava SOLIDIFIES.
11
Q
What do magnetic materials in the lava line up along?
A
Along the Earth’s magnetic field.
12
Q
What happens to the Earth’s magnetic field over time?
A
It changes.
13
Q
What can geologists do in terms of rocks?
What does this evidence support?
A
They can date rocks and track the slow movement of continents using changes in magnetic patterns, linked to radioactive decay.
This supports the PLATE TECTONIC THEORY.
14
Q
What are rocks and where are they found?
A
Rocks are raw materials found buried in the Earth’s crust.
15
Q
What are the three important raw materials?
A
- Coal
- Salt
- Limestone
16
Q
In Britain, where was coal, salt and limestone found?
What provided good transport links?
A
- Coal was found in South Lancashire.
- Salt was found in Cheshire.
- Limestone was found in the Peak District.
The port of Liverpool and the canal system provided good transport links.
17
Q
What is limestone?
A
A sedimentary rock. It’s grey/white and mostly consists of calcium carbonate.
18
Q
How is limestone formed?
A
- Shellfish died forming sediments on the seabed.
- Sediments compacted and hardened to form limestone (a sedimentary rock).
- Tectonic plate movements pushed the rock to the surface.
- Gradually the rocks above were eroded away until the limestone was exposed. It was held by the fluids flowing through pores in the sediment which deposit natural mineral cement.
19
Q
What is coal?
A
Mainly carbon, quite hard and black in colour.
20
Q
How is coal formed?
A
In wet swampy conditions when plants like trees and ferns died and became buried. This excluded oxygen, slowing down decay.
21
Q
How is salt formed?
A
- Rivers bought DISSOLVED salts into the sea.
- Climate warming EVAPORATED the water, leaving salt that mixed with sand blown in by the wind.
- Rock salt formed and was buried by other sediments.
22
Q
What does coal provide as evidence?
A
It contains fossils of the plants that formed it.
23
Q
What does limestone provide as evidence?
A
It contains bits of shell fragments from sea creatures.
24
Q
What does rocksalt provide as evidence?
A
It contains different-shaped water-eroded grains and wind-eroded grains.
25
What can ripple marks in rocks indicate as evidence?
Indicates water flow from rivers or waves in the sea.
26
What is rock salt a mixture of?
Salt and impurities
27
Where is rock salt fond?
Deep in underground deposits.
28
What are the two methods of mining of rock salt?
1. Normal mining
| 2. Solution mining
29
How is Normal Salt Mining performed?
| What can the rock salt obtained be used for?
Rock salt is drilled, blasted and dug out and brought to the surface using machinery.
Most rock salt obtained through this type of mining is used on roads to stop icing.
The salt can also be separated out and used to enhance the flavour in food or for chemicals.
30
What are the stages in Solution Mining?
1. Mining water is injected into the salt deposit through the outer pipe.
2. This dissolves the salt to make saltwater solution (brine).
3. Pressure forces the brine up to the surface through the inner pipe.
4. The brine is then stored in wells above the surface and pumped to a refining plant when needed.
5. Impurities are removed from the brine in the refining plant and is then pumped into containers. The brine is then boiled to make the water evaporate, leaving the salt behind.
31
What are the 2 main products that are produced using Solution Mining?
1. Table salt
| 2. Salt used for chemical production
32
Why is rock salt spread on icy roads (3) ?
1. The rock is insoluble but the sand in the rock salt gives grip.
2. It shows up so people know when roads have been gritted.
3. The salt in solution lowers the freezing point, preventing ice forming as easily.
33
What can both types of mining cause as an impact to the environment? How can it affect the surroundings?
Mines can collapse into the holes. This is called SUBSIDENCE.
It can affect buildings near the mines, including people's homes.
34
How is the risk of subsidence reduced?
By leaving well-supported caverns in mines (e.g. supported by pillars of rocks).
35
What is another environmental problem, other than subsidence, of mining?
It needs a lot of energy which usually comes from burning fossil fuels. This uses up finite resources and produces pollution.
36
Other than normal mining and solution mining, how else can salt be obtained?
Evaporating seawater.
Seawater flows into specially built shallow pools and is left to evaporate in the sun, leaving the salt behind. This is repeated several times and the salt is then collected.
37
What is the benefit of obtaining salt from seawater?
It produces the purest salt - it can nearly be 100% sodium chloride.
38
What are the 2 main uses of salt?
1. Flavour enhancing
| 2. Used as a preservative
39
What can a higher salt level prevent?
Bacteria growth
40
What can eating too much salt lead to?
1. It may cause HIGH BLOOD PRESSURE.
This can lead to strokes and heart attacks.
2. Evidence that eating too much salt could increase chances of getting stomach cancer, osteoporosis and renal failure.
41
What is salt classified as in terms of its outcomes?
It's a HAZARD.
42
What is an example of a RISK?
The chance of getting ill, and the consequences if you did.
43
What is an example of an independent food safety watchdog? What do they do?
Food Standards Agency (FSA).
| They provide advice to the government and the public about food safety and health.
44
What is the Guideline Daily Amounts (GDA)?
Issued guidelines from the FSA that indicate how much salt people should have in a day, depending on their age.
45
What can food labels tell us in terms of salt intake?
They often tell you the PERCENTAGE of the GDA for an adult a product will supply.
46
What are the 2 health departments and what 2 things are they responsible for?
Department of Health (DH) and the Department for Environment, Food and Rural Affairs (Defra).
They're responsible for:
1. Carrying out risk assessments for chemicals in food.
2. Advising the public about how food affects health.
47
What are 2 reasons as to why food manufacturers still include salt in their products despite too much salt being unhealthy?
1. The cost of REFORMULATING recipes is too great.
| 2. The product may not taste as great or last as long (therefore sales drop).
48
What do alkalis make indicators do?
Change colour.
49
In alkalis, what colour does litmus turn into?
BLUE. (red in acids).
50
What is neutralisation?
When alkalis NEUTRALISE acids to make SALTS.
51
What is the word equation for neutralisation?
acid + alkali → salt + water
52
What are 4 main uses of alkalis?
1. Dyeing cloth
2. Neutralising acid soil
3. Making soap
4. Making glass
53
What were the 2 traditional sources of alkalis?
1. Burnt wood
| 2. Stale urine
54
In the past, what was one major use of soap for?
Cleaning wool
55
How was soap made?
Mixing the ashes from burnt wood (potash) with animal fat and boiling it.
56
In coastal areas, what was used to neutralise acidic soils?
Seaweed or seaweed ash (called soda).
57
What was the first alkali to be manufactured? How was this done?
LIME (Calcium Oxide).
| Done by heating limestone (calcium carbonate) in a lime kiln, using coal as fuel.
58
What are 4 uses of lime?
1. Neutralising acidic soils
2. Making glass when heated with sand
3. Removing impurities when iron is made.
59
Before modern dyes, how were clothes coloured?
Using dyes from plants and animals.
60
What is Alum? How was it purified?
A mordant that sticks dye to a fabric. It was purified by reacting it with ammonia contained in stale urine.
61
What was the LeBlanc Process?
A process that made Sodium Carbonate by reacting salt and limestone, heated with coil.
62
What was the problem of the LeBlanc Process?
It gave off large amounts of hydrogen chloride (an acidic, harmful gas).
It also produced heaps of solid waste, called galligu, that slowly released hydrogen sulfide which is toxic and smells like rotten eggs....
63
What can the harmful hydrogen chloride from the LeBlanc Process convert to (2) ?
Useful substances such as:
1. Chlorine used to bleach textiles prior to dyeing
2. Hydrochloric acid,a starting material for making other chemicals.
64
How is chlorine made?
By reacting hydrochloric acid and manganese dioxide.
65
What does oxidation do to hydrogen chloride?
Converts Hydrogen chloride into CHLORINE.
66
In terms of pH, what is an alkali? What colour does it turn indicators to?
It is a solution with a pH greater than 7.
| It turns pH indicator blue-violet.
67
What are 2 SOLUBLE types of alkalis?
1. SOLUBLE metal hydroxide
| 2. SOLUBLE metal carbonate
68
What are 3 examples of soluble hydroxides?
1. Sodium Hydroxide - NaOH
2. Potassium hydroxide - KOH
3. Sodium Carbonate - Ca(OH)2
69
What are 2 examples of soluble carbonates?
1. Sodium Carbonate - Na2 CO3
| 2. Potassium Carbonate - K2 CO3
70
What are insoluble metal hydroxides/carbonates known as?
BASES.
71
What are the 2 reactions of bases reacting with acid?
1. Hydroxide + Acid → Salt + Water
| 2. Carbonate + Acid → Salt + Water + Carbon Dioxide Gas
72
What are the 3 main examples of acids (with its formula) ?
1. Hydrochloric Acid - HCl
2. Sulfuric Acid - H2 SO4
3. Nitric - HNO3
73
What are the 3 main examples of salts (with its formula) ?
1. Chloride - Cl
2. Sulfate - SO4
3. Nitrate - NO3
74
What is chlorine used for?
Water treatment
75
What are 3 ways in which chlorine is important for water treatment?
1. Kills disease-causing microorganisms.
2. If the correct amount is added, enough chlorine remains in the water to kill bacteria that might enter the supply AFTER treatment, further down the pipes.
3. It prevents the growth of ALGAE, gets rid of bad tastes and smells and also removes DISCOLOURATION caused by organic compounds.
76
What 2 diseases could rise if chlorine wasn't added to water?
1. Cholera
| 2. Typhoid
77
What is the correlation of adding chlorine in water?
A correlation exists between the START of water chlorination in the UK and a FALL in the number of deaths from typhoid.
78
Despite the use of chlorination of water, what did the World Health Organization and the USA estimate in 1995?
That a BILLION PEOPLE in the world don't have access to clean drinking water.
79
Why is it that many developing countries don't have access to clean drinking water (2) ?
1. It's very expensive to get clean water.
| 2. Some people live in isolated rural areas and must travel lots of miles to get any water at all.
80
How else, other than reacting hydrochloric acid and manganese dioxide, can chlorine be made?
(hint: Hydrogen....)
Separation of compounds of hydrogen chlorides (HCl)
| as well as salt (sodium chloride).
81
What is the reaction of oxidation of hydrogen chloride?
4HCl + O2 → 2CL2 + H2O
82
What are 2 negative impacts on health of chlorinating water?
1. Chlorine can react with chlorinated hydrocarbons (from organic compounds) many of which are carcinogenic (cancer-causing). But this increased cancer risk is small compared to the risks from untreated water.
2. Chlorine gas is a toxic gas when breathed in. It irritates the respiratory system. Liquid chlorine can cause sever chemical burns.
83
What is electrolysis?
The separation of compounds using an electric current.
84
What does the electrolysis of brine make?
1. Chlorine gas
2. Hydrogen gas
3. Sodium Hydroxide solution
85
What is the benefit of electrolysis of brine?
The products made have uses, so there is no waste.
86
What is the anode and what is the cathode in electrolysis?
ANODE - Positive electrode
| CATHODE - Negative electrode
87
What is one disadvantage of electrolysis?
Large amounts of electricity is needed (from fossil fuels) so it's expensive.
88
What is one way of electrolysing brine continuously?
MEMBRANE CELL method
89
During electrolysis of brine, where do the products form?
Chlorine forms at the ANODE.
| Hydrogen forms at the CATHODE.
90
What 6 uses are there with chlorine from brine electrolysis?
1. Disinfectants
2. Killing bacteria
3. Household bleach
4. Plastics (PVC) in medicines and crop protection.
5. Hydrochloric Acid (HCl)
6. Insecticides
91
What 3 uses are there with hydrogen from brine electrolysis?
1. Ammonia
2. Margarine
3. Fuel in fuel cells, and for welding and metal cutting.
92
What are 5 uses of sodium hydroxide from brine electrolysis?
1. Soap
2. Ceramics
3. Organic chemicals
4. Paper pulp
5. Oven cleaner
6. Household bleach (made by reacting chlorine with sodium hydroxide).
93
What are 3 environmental impacts of brine electrolysis?
1. Large sale electrolysis needs a lot of energy, by burning fossil fuels which releases CO2 and uses up finite resources.
2. Mercury is a toxic chemical in brine electrolysis plants. It contaminates fish in rivers and people who ate the fish became ill.
3. Asbestos is often used in industrial electrolysis. It's toxic and causes lung cancer.
94
What is used to assess how dangerous substances are?
Risk assessments
95
What can toxic chemicals do in an environment:
They can be carried over large distances and accumulate in food chains, ending up in human tissues.
96
What are the 4 pieces of information needed to decide the level of risk of a particular chemical?
1. How much of it is needed to cause harm
2. The chance of it escaping into the environment.
3. How much will be used.
4. Who or what it may affect.
97
What is the misconception of risk levels by people?
Many people PERCEIVE the risk is greater for newer chemicals with less familiar names, while the ACTUAL risk could be less.
98
What is PVC? What is it used for?
PVC (Polyvinyl chloride) is a common polymer that contains carbon, hydrogen and chlorine. They're used in electrical wiring because of its heat and fire resistance which are caused by PCBs.
99
What are the problems of PCBs?
They can leach out of the plastic and into water sources. The PCBs are toxic and they can accumulate animals and end up being eaten by humans.
They're also a relatively new thing so the long-term studies are not possible. Many people dispute the risks.
100
What is Life Cycle Assessment (LCA)?
This looks at each stage of a product's life to assess its impact on the environment.
101
What are the 4 stages in the Life Cycle Assessment?
1. Choice of Material - how are the materials gained? Is it from a finite/renewable source?
2. Manufacture - does it produce a lot of energy? Can the waste be recycled? Are any pollutants made?
3. Using the product - e.g. fertilisers leads to eutrophication, paint gives off fumes, burning fuels releases greenhouse gases, etc.
4. Product Disposal - can it be incinerated or disposed in a landfill? Will it take up space and pollute land and water?
102
To produce a fair and accurate LCA, what is required?
A lot of data is required.
103
What are 2 examples of aspects that are hard to measure in the LCA?
1. e.g. a lifetime of a car
| 2. e.g. its disposal method (it can vary)
