C3 Chemicals In Our Lives - risks and benefits Flashcards
How do geological changes occur
Do you logical changes happen by small movements of tectonic plates. Plates can move by sliding past each other, colliding or pulling apart
Tectonic plate
Section of earths crust that slowly moves relative to other plates
What do plate collisions create
Plate collisions build mountain ranges, which Road overtime
Explain the making of Britain
- Over millions of years, Britain has moved across the earth surface
- 600 million years ago, England and Wales were separated from Scotland by ocean, and both were near the South Pole
- Gradually, different continents gifted and crashed together to form a supercontinent, Pangea
- Britain is made from rocks from different ancient continents
- Originally, Britain was near the Equator with a warmer climate
- Different climates existed in Britain, from tropical swamps to ice ages
Describe the stories in magnetism
- As volcanic lava solidifies, igneous rocks are formed
- Magnetic materials in the lather line up along the earth’s magnetic field
- The earth’s magnetic field changes over time
- Geologist can Dave rocks and track the slow movement of continents using changes in magnetic patterns, linked to radioactive decay
- This evidence supports the plate tectonic theory
Supercontinent
Very large landmass
Lava
Molten rock (magma) from beneath the earth surface when it’s erupts from a volcano
Igneous rock
Rock formed by the solidification of molten magma or lava
Magnetic field
Space in which a magnetic material exerts a force
Plate tectonic theory
The theory that explains how changes to the earth surface occur at tectonic plate boundaries
Describe the three from materials buried in the earth’s crust
Rockstar role material sound buried in the earth’s crust. Coal, salt and lime stone are three important raw materials
Scribe the distribution of the role materials in England
- 200 years ago the industrial revolution started in north-west England. Chemical industries build up near to raw materials and transport links
- There was coal in South Lancashire, salt in Cheshire and limestone in the peak district. The Port of Liverpool and the canal system provided good transport links
How did limestone form in Britain
Limestone formed wall England was covered by sea:
- Shellfish died forming sediments on the seabed
- Sediments compacted and hardened to form limestone, A sedimentary rock
- Tectonic plate movement is pushed the rock to the surface
- Gradually the rocks above where eroded away until the limestone was exposed
Where did Coal form
Coal formed in wet swampy conditions when plants like trees and ferns died and became buried. This excluded oxygen, slowing down decay
Where did salt form
Salt phoned while Cheshire was covered by shallow sea:
- Rivers brought dissolved salts into the sea
- Climate warming evaporated the water, leaving so that mixed with sand blown in by the wind
- Rocksalt formed and was buried by other sediments
Where did your ologists find evidence for limestone call and salt formation
Geologists have found evidence for limestone, coal and salt formation
- Coal contains fossils of the plants that formed it.
- Limestone contains bit of shell fragments from sea creatures.
- Rock salt contains different shaped water eroded grains and wind eroded grains.
- Ripple Marks in rocks indicate what flow from rivers or waves in the sea
What is salt used in
The food industry; as a source of chemicals; to treat icy roads in winter
Where can salt be obtained from
Collecting and evaporating seawater; mining underground deposit of rocksalt
Why is rocksalt spread on icy roads
- The rock is insoluble but the sand in the rock gives grip
- It shows up so people know when roads have been gritted
- The salt insolation lowers the freezing point, preventing ice forming as easily
Name the rock salt mine in Britain and what it does
- Only one rock salt mine exists Britain (in Cheshire). It mines 1 million tons a year
- If more salt is needed it is usually imported
- Salt extraction from seawater is only economical in hot climates
- Purer salt can be obtained by solution mining, which is mainly automatic
What are the disadvantages of mining rock salt
- Mining rocksalt and solution mining can cause subsidence. About half the rock salt could not be made, as it is left in place for support
- Mining can allow water in mines, which may let salt leach out into water supplies, contaminating them
- Evaporating salt from seawater takes up a large areas and spread salt into the local environment, damaging habitats
What are the risks of eating salt in food
- Salt is used in food both as a flavouring and as a preservative
- A higher salt level prevent bacteria growth
- Too much salt is bad for your health
- Many people add worried about salt intake, which can Cause high blood pressure m, heart failure and strokes
- This means salt is classified as a hazard
How are the salt risks handled
- A risk is the chance of getting ill, and the consequences if you did
- Risks can be estimated by measuring salt intake
- Food labels show the amount of salt contained in the product
- Knowing the risk allows you to make decisions
What does the government do about the salt intake
The government Department of health (DH) and the Department of Environment, Food and Rural Affairs (Defra) are responsible for carrying out risk assessment for chemicals in food and advising the public about how food affects health
