GCSE Chemistry C14 - The Earth's Resources

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What are finite resources?
Those that are being used up at a faster rate than they can be replaced. If we carry on uing them at current rates, they will run out.
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What are renweable resources?
Those that can be replaced at the same rate which they are used up.
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What are some examples of finite resources?
Metal ores used to extract metals and crude oil used to make polymers and fuels for transport.
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What are some examples of finite resources?
Using wood chips instead of fossil fuels to fuel power stations and usuing ethanol to produce ethene and produce more sustainable plastics.
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What are the stages in water treatment? (from the resevoir to having chlorine added)
Passes through a screen which catches twigs and leaves, through a steelement tank so sand and soil settle out, aluminium sulfate and lime are added and dirt sinks to the bottom of the water and it is dumped into a landfill site and chlorine is added.
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Why is chlorine added during water treatment?
To kill any harmful bacteria in the water.
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What is the last stage in the water cycle so it can be pumped into our homes?
The pH of the water is checked and corrected to be neutral. It is then stored in large tanks and service resevoirs.
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Why is distillation an expensive process?
Due to the high energy costs of boiling large volumes of water in a deslination plant despite reduced pressures used.
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What is flash distillation?
When energy costs of distilling water are reduced as a lower pressure is used and water boils below 100 degrees celsius.
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What is desalination?
Converting salty water to potable, useable water.
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What is reverse osmosis?
This uses membranes to seperate the water and the salts dissolved in it. No heating involved, but still requires high pressures.
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What is the first stage of sewage treatment?
Screening, large solid objects and gri are removed from the water by a metal grid.
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What is the second stage of sewage treatment?
Primary treatment, large rotating paddes push sludge towards the centre of the tank where it moves to another tank for further treatment whilst the effluent (watery liquid) above the sludge flows into the next tank.
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What is the third stage of sewage treatment?
secondary treatment, in the next tank useful bacteria break down any remainingorganic matter and harmful microorganisms. The tank is aerated by bubbling air through the waste water.
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What is the fourth stage of sewage treatment?
Final treatment, in the final tank useful bacteria settle at the bottom of the tank as sediment and then transported back to the secondary tank or in the tank where the sludge is treated. The water is safe enough to go back into rivers..
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What happens to sweage sludge?
Dried out and used as fertiliser on farmland or burnt and used to generate electricity.
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What are the breakdown products of sewage treatment?
Include biogas, which can be burnt and power the sewage treatment tank or provide electricity to the surrouding area.
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What are the two methods to obtain copper metal from the ore?
1. Sulfuric acid is used to produce copper sufate solution before extracting the metal. 2. Through smelting, copper ore is heated to a high temperature in a furnace with air, producing impure copper.
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Which electrode is impure copper at in electrolysis to make pure copper?
The positive electrode.
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What is bioleaching?
Bacteria feed on low-grade metal ores. By a combo of chemical and biological processes, copper ions can be obtained from waste copper ore and scrap iron and electrolysis is used to extract copper from the copper ions. This is a slow process.
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What is phytomining?
When plants that can absorb copper ions are grown on soil contaiing low-grade copper ore.
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What is a life cycle assessment?
Used to assess the impact of getting the raw materials for a product, making product + packaging, using and resuing product and product's disposal.
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How is an LCA carried out?
Listing all material inputs/outputs to the environment, evaluating impacts from these inputs and outputs and then using this to make decisions about using one material, product or process over another.
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What are the main stages in an LCA?
Raw material extraction., manufacure, use/reuse/maintenance and recycle/waste management.
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Why are some LCAs not completely objective?
As there are global impacts e.g. global warming regional impacts e.g. acid rain and local impacts e.g. toxic emissions into a stream to think about to.
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What does an LCA not tell us?
The differences in cost or peformance between products or materials.
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What are the main aims of campaigns to 'reduce, reuse and recycle'?
Reduce our use of limited resources, our use of energy and the watse we produce.
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Why should we recycle aluminium?
To conserve te earths reserves of aluminium ore. It is extracted from molten aluminium oxide at high temps via electrolysis which requires lots of electrical energy. Recycling saves energy and money as it doesn't involve elctrolysis.
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Why is copper difficult to recycle?
As it is often alloyed with other metals like zinc to make brass. Impure copper from recycling must be purified.
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What are the benefits of recycling?
Conserves the earth's reserves of metal ores, prevents pollution from extraction of metal from its ore. Mines also create huge pits that destroy the landscape and habitats, groundwater can also beome acidic.
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Other cards in this set

Card 2

Front

What are renweable resources?

Back

Those that can be replaced at the same rate which they are used up.

Card 3

Front

What are some examples of finite resources?

Back

Preview of the front of card 3

Card 4

Front

What are some examples of finite resources?

Back

Preview of the front of card 4

Card 5

Front

What are the stages in water treatment? (from the resevoir to having chlorine added)

Back

Preview of the front of card 5
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