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59 Cards in this Set
- Front
- Back
What do geologists do ? |
They explain most of the past history of the surface of the earth in terms of processes that can be observed today |
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What do movements of tectonics plates mean ? |
They mean that the parts of ancient continents that now make up Britain have moved over the surface of the earth |
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How do geologists use magnetic clues in rocks to track the very slow movement of the contents over the earths surface ? |
1. tectonic plates move away from each other under the sea 2. the exposed magma rises up through the sea floor 2. it solidifies to form new crust 3. the crust is then magnetised by the earths magnetic field (the earths magnetic field swaps direction every half million years, so the rocks are either normal polarity or reversed polarity when they cool. This pattern can be used to estimate the age of parts of the earths crust) |
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What does the movement of continents mean? (in terms of Britain) |
it means that different rocks in Britain formed in different climates |
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What 4 processes in England have led to the formation of valuable resources (of coal, limestone, salt) |
1. mountain building 2. erosion 3. sedimentation 4. dissolving and evaporation |
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What type of rock is limestone and what is it formed from? |
it is a sedimentary rock formed from seashells |
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What colour is limestone and what does it mostly consist of ? |
it is grey/white and mostly consists of calcium carbonate |
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How are sedimentary rock formed ? |
They are formed from layers of sediment laid down in lakes or sea |
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Where does the sediment that makes sedimentary rocks come from ? |
it comes from shells and bones of sea creatures or from the erosion of pre-existing rocks |
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What is erosion ? |
erosion is the natural weathering of large pieces of rock by rain and wind |
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what does erosion create and what happens to what is created ? |
it creates tiny particles of sediment that are washed away and end up at the bottom of the sea or lake. |
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What happens to layers of sediment over millions of years ? |
it gets buried under more layers of sediment and the weight pressing down squeezes out the water |
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how are sediment particles held together to form rock ? |
fluids flowing through pores in the sediment deposit natural mineral cement |
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How is coal formed ? |
it is formed over millions of years by the fossilisation of layers of plant matter |
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what colour is coal and what does it mainly consist of ? |
it is black and mainly consists of carbon |
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how is hard coal formed ? (mountain building) |
when coal deposits are put under high pressures and temperatures. (this can happen during the process of mountain building) |
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What happens during evaporation to form sedimentary rocks? |
salt is left behind by evaporation |
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how is salt obtained in Britain ? |
it is extracted from underground deposits |
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why do geologists study sedimentary rocks ? |
to find evidence go the conditions under which they where formed |
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Why do geologists look at fossils ? |
they tell you about the age of the rock, as well as the conditions when it was formed |
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What does sedimentary rock formed under water contain ? |
it contains shells and ripples on it created by the sea or rivers |
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what can you tell by the shape and grains found in sedimentary rocks ? |
you can tell if it was formed under water (water-bourne grains) or on the surface (air- blown grains) |
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Where do chemical industries grow up ? |
where resources are available locally e.g. salt, limestone and coal in north west England |
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Why is salt important ? (3) |
1. for the food industry 2. as a source of chemicals 3. to treat the roads in winter |
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chemical name for salt? |
Sodium Carbonate |
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name 2 places where salt can be obtained ? |
1. from the sea 2. from underground salt deposits |
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How is underground salt obtained by mining ?
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1. Rock salt is drilled, blasted and dug out and brought to the surface using machinery |
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What is underground rock salt used for ?
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1. it is used on roads to stop ice from forming 1. the salt can be separated and is used on foods or for making chemicals |
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How does solution mining work ? |
1. water is injected into the salt deposit through the outer pipe 2. the water dissolves the salt to make a saltwater solution (brine) 3. pressure forces the brine up to the surface through the inner pipe 4. brine is then stored in wells above the surface and pumped to a refining plant. 5. impurities are removed from the brine in the refining plant and it is then pumped into containers. 6. The brine is then boiled to make the water evaporate living just the salt |
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what is most of the salt made in solution mining use for ? |
1. table salt 2. chemical production |
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why does the method used to obtain salt depend on how the salt is being used ? |
because some methods produce purer salts than others e.g. salt mining does not produce as purer salt than solution mining so the salt is used on roads and not for human consumption. |
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How do methods of obtaining salt (mining) effect the environment ? |
1. land above mines can collapse into the holes- this is called subsidence 2. a lot of energy is need for mining, which usually comes from burning fossil fuels - this uses up finite resources and produces pollution |
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Advantages of adding slat to food ? |
1. flavouring 2. preservative |
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What are the health implications of eating too much salt ? |
1. high blood pressure - this leads to strokes and heart attacks 2. can increase the chance of getting stomach cancer |
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What do the government departments (Department of Health, Department for environment, food and rural affairs) have a role in ? |
1. carrying out risk assessments in relation to chemicals in food to make sure they are safe 2. advising the public to how food affects their health |
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What where alkalis needed for before industrialisation ? (4) |
1. to neutralise acid soils 2. make chemicals that bind natural dyes to cloth 3. convert fats and oils to soap 4. to manufacture glass |
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What are traditional sources of alkali ? (2) |
1. Burnt wood 2. Stale urine |
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What do alkalis do ? |
They neutralise acids to make salts |
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what are 2 alkalis ? |
1. soluble hydroxide 2. carbonates |
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what did, increased industrialisation in the 19th century lead to ? |
it led to a shortage of alkalis |
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how did the process for manufacturing alkali from salt and limestone using coal as a fuel cause pollution ? |
it released large volumes of an acid gas (hydrogen chloride) and creating heaps of waste that slowly released a toxic and foul smelling gas (hydrogen sulfide) |
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How can pollution problems sometimes be solved? |
by turning wastes into useful chemicals |
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when oxidized what does hydrogen chloride convert to ? |
chlorine |
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When hydrogen chlorine is oxidized to give chlorine, what are the properties of the compound like ? |
the properties the compound are completely different from the elements from which it is made |
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What is chlorine used for ? |
1. to kill microorganisms in domestic water supplies 2. as bleach |
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what was introduced to drinking water that made a major contribution to public health ? |
chlorination of water
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what is the disadvantage of chlorinating drinking water ? |
possible health problems from traces of chemicals formed by the reaction of chlorine with organic materials in the water |
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what can be used to bring about a chemical change and make new chemicals ? |
an electric current, through the process called electrolysis |
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How is chlorine obtained? |
by the electrolysis of salt solution (brine) |
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important uses by industry of the sodium hydroxide produced by electrolysis of brine ? |
1. soap 2. ceramics 3. organic chemicals 4. paper pulp 5. oven cleaner 6. household bleach |
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important uses by industry of the chlorine produced by electrolysis of brine ? |
1. disinfectants 2. killing bacteria (swimming pools and in domestic water supplies) 3. household bleach 4. plastics (e.g. PVC) 5. hydrochloric acid 6. insecticides |
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important uses by industry of the hydrogen produced by electrolysis of brine ? |
1. used to make ammonia 2. used to change oils into fats for making margarine 3. used as a fuel in fuel cells, and for welding and metal cutting |
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environmental impacts of large scale electrolysis ? |
1. requires a lot of energy, which comes from burning fossil fuels, then releasing co2 and using up finite resources 2. mercury is toxic and can get into rivers, and kill fish, and make people ill 3. Asbestos is used and it it is toxic and can cause lung cancer |
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What is the problem with the a large number of industrial chemicals with widespread uses including consumer products?
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There is inadequate data to judge whether they are likely to present a risk to the environment and/ or human health |
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Why do some toxic chemicals cause problem? |
1. they persist in the environment 2. they can be carried over large distances 3. can accumulate in food and human tissues |
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What is PVC ?
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it is a polymer that contains chlorine as well as carbon and hydrogen |
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What is the problem with the plasticizes used to modify the properties of PVC ? |
They can leach out from the plastic into the surroundings where they may have harmful effects |
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What does a Life Cycle assessment involve (consider) |
the use of resources including -water -the energy input or output - the environmental impact of all these stages |
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Life Cycle assessment stages |
1. making the material from natural raw materials 2. making the product from the materiel 3. using the product 4. disposing of the product |