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79 Cards in this Set
- Front
- Back
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What is the outer layer of the Earth made up of? |
about 12 tectonic plates |
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What are tectonic plates? |
Giant slabs of rock (about 12, comprising crust and upper mantle) that makes up the Earth's outer layer |
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What makes tectonic plates move? |
Convection currents underneath them |
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What do scientists use to track a continents movements? |
They use magnetic clues in rocks like magnetite |
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What has the movement of continents meant? |
That parts of ancient continents that now make up Britain have moved over the surface of the Earth |
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What processes form rocks? |
-Sedimentation and compression -Erosion -Evaporation -Mountain Building |
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What did sedimentation and compression do? When does it occur? |
It formed peak district limestone. |
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When does sedimentation occur? |
When dead sea animals fell to the bottom of warm seas near the equator. |
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What has erosion formed? |
Sandstone |
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How has erosion formed sandstone? |
Rocks by rivers eroded to form sand which was then deposited in layers. |
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What has evaporation done? |
Formed rock salt |
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How has evaporation formed rock salt? |
Seas moved inland, and its water evaporated. |
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How was salty water originally formed? |
When salts from rocks dissolved in water that flowed over them |
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What has mountain building done? |
Pushed coal towards the surface in the peak district |
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How was coal formed? |
When tree ferns in swamps died and were compressed then heated. |
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Where have chemical industries grew up? |
Near to where resources are available |
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How do we know how rocks were made? |
By looking at: -Fossils -Sand grains -Ripples -Shell fragments |
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Why are fossils in rocks important? |
Different animals lived at different times, so their fossils tell us about the ages of the rocks they are in |
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Why are sand grains in rocks important? |
By comparing sand grains in deserts and rivers to sand grains in sandstone, tells us what sort of sand formed the sandstone |
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Why are ripples in rocks important? |
The shapes of the ripples in rocks give us clues about whether sandstone was made from river bed sand or desert sand |
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Why are shell fragments in rocks important? |
Tiny shell fragments in limestone tell us about the conditions when the rock formed. |
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What are uses of salt? |
food, to treat icy roads, and as a source of chemicals. |
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What is the chemical name for salt? |
Sodium Chloride (NaCl) |
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Where does salt for food come from? How? |
Some of it comes from the sea. The water evaporates, leaving salt behind |
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Where is the most salt for food made? Why? |
In hot countries with dry climates because the energy costs are lower |
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What is rock salt made of? |
A mixture of salt and clay |
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What is the main use for rock salt? Why? |
De-icing roads, because it doesnt have to be pure |
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How do we get rock salt? |
By mining underground with big machines |
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How does the chemical industry get salt? |
Through solution mining? |
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What must the salt be for the chemical industry? |
It must be pure |
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How does solution mining work? |
Water is pumped into the rock salt, the salt dissolves in the water underground, then the solution is pumped to the surface and solid salt can be extracted from the solution |
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What is brine |
A solution of sodium chloride in water |
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What is a solution of sodium chloride in water called? |
Brine |
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What is subsidence? |
the sinking of the grounds surface when it collapses into a hole beneath it |
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What caused subsidence in the past? |
Solution mining |
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How do miners avoid the issues of subsidence? |
By leaving in pillars |
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Why is salt added to food? |
-To add flavour -As a preservative, to stop food going off |
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What can eating to much salt do? |
It can raise your blood pressure and increase your chances of having a stroke or a heart attack |
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Why do governments do risk assessments on food? |
So they can tell the public about the risks |
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Before industrialisation, how were alkalis used? |
-Neutralise acid soil -Make chemicals to bind dyes to cloth -Convert fats and oils into soap -Make glass |
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When alkalis dissolve in water, what do they do to its pH? |
Make it above 7 |
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What is the word equation to show how sodium hydroxide neutralises an Hydrochloric acid? |
sodium hydroxide+hydrochloric acid-> sodium chloride+water |
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When alkalis react with acids, what do they form? |
salts |
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What is sodium hydroxide? |
An alkali |
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What is sodium chloride? |
A salt |
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What else do alkalis include? |
soluble hydroxides and soluble carbonates |
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When soluble hydroxides react with acid, what do they form? |
a salt and water |
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When soluble carbonates recat with an acid, what do they form? |
A salt, water, and CO2 |
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Before the industrial revolution, how were alkalis obtained? |
From burnt wood and stale urine |
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In the industrial revolution, what was invented due to a shortage? |
A new method of making alkali |
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What did the new method of making alkali that was first used in the indutrial revolution have as its raw materials? |
salt(sodium chloride), limestone(calcium carbonate) and coal |
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What did the new process for making alkali have as its waste products? |
-Acidic hydrogen chloride gas -Solid waste, which emitted toxic, smelly hydrogen and sulfide gas. |
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When and who worked out how to use one of the pollutants from the new method of making alkali? |
Henry Deacon in 1874. Hydrogen Chloride, could be oxidised to make chlorine. |
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How can chlorine be used? |
-As a bleach -To whiten paper and textiles |
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What can sewage contaminated water contain? |
microorganisms that cause cholera and typhoid |
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By adding chlorine to water, what does it do? |
Kill microorganisms, meaning that fewer deaths are cuased by waterborne diseases |
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What are possible disadvantages of chlorinating water? |
When it reacts with organic matter, THMS(trihalomethanes) may form which some people think can cause cancer. |
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How is chlorine made today? |
from sodium chloride solution (brine) |
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How can we cause chemical changes in brine? |
By passing electricity through it |
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How does passing electricity through the brine cause a chemical change? |
The sodium and chlorine, and hydrogen and oxygen are rearranged to make new products |
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What does chlorine gas do? |
It can be used to treat water, make bleach, plastics, and HCl |
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What does hydrogen gas do? |
It is a fuel, and used to make HCl |
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What does sodium hydroxide solution do? |
It can make soap, paper and bleach |
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What are the new products from the electrolysis of brine? |
Chlorine gas, Hydrogen gas, Sodium hydroxide |
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What does the electrolysis of brine need? |
Electricty |
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Are chemicals risky? |
In big quantities, some may harm health |
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Is there evidence that tiny amounts of chemicals in our blood can be harmful? |
No |
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Why are some synthetic chemicals banned? |
Because everyone agreed they are harmful because: -They dont break down -They can travel in air and water -they build up in the fatty tissues of mammals |
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What is PVC made up of? |
chains of carbon, hydrogen and chlorine atoms |
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What is soft PVC used to make? |
electric wire insulation, clothing |
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What is harder PVC used to make? |
Window frames, underground water pipes |
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What is PVC film used to make? |
hospital bags and drip bags |
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How is PVC softened? |
By adding plasticisers |
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What are plasticisers made of? What are their risks? |
They are small molecules. They can escape from plastics and dissolve into liquids that are in contact with it, possibly causing cancer and infertility |
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What do Life Cycle Assessments consist of? |
Assessing: -The use of resources, including water -The energy inputs and outputs -The environmental impact |
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What could be the environmental impact when materials are being made? |
Raw materials to make material energy and water in processing |
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What could be the environmental impact when manufacturers make the product? |
materials to make product energy and water in manufacture |
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What could be the environmental impact of people that use the product? |
energy required to use the product energy water chemicals needed for maintenance |
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What could be the environmental impact when people get rid of the product? |
energy to take the product away space to store waste |
