C12 Flashcards
Where do natural resources come from?
Earth, sea or air.
What is a naturla resource?
Something that forms without human input.
What are the earths resources used for?
To provide warmth, shelter, food and transport
What can be created with natural resoruces?
A synthetic product improved by mand made processes
How agriculture is used to create natural resources?
Provides conditions where natural resources can be enhanced for our needs
What can natural resources supplemented by agriculture provide?
Food, timber , clothing and fuels
What are finite resources?
Aren’t formed quickly enough to be considered replaceable. They include fossil fuels , nuclear fuels such as uranium and plutonium, also minerals found in the earth. After extraction they usually go through man made processes to provide fuels and materials. Examples is fractional distillation
How does extracting finite resources have its risks?
- many modern materials are made from finite resources
- have to balance social , economic and environmental factors
What is potable water?
Water thats been treated or is naturslly safe for humans to drink , it is essential for life.
Why is potable water not pure?
Pure water only contains h2o molecules whereas potable also contains dissolved susbtances.
What needs to happen for water to become potable?
Decrease the levels of dissolved salts, so it has a ph between 6.5 and 8.5, and also to remove bacteria and other microbes .
What is fresh water?
Water that doesn’t have much dissolved in it, an example is rain water . Still needs to be treated to make it potable.
How to find water to make potable water in the uk?
Rain provides water with low levels of dissolved substances (fresh water) that collects in the ground and in lakes and rivers .
Ways of making water potable?
Filtration
Sterilisation
Hoe to use filtration to produce potable water?
A wire mesh screens out large twigs and then gravel and sand beds filter out any other solids
How sterilisation can help make water potable ?
Water is sterilised to kill harmful bacteria or microbes . This can be done by bubbling chlorine gas through it or by using ozone or ultraviolet radiation
What is desalinisation?
If supplies of fresh water are limited , and there is only sea or salty water , it may be required. Can be done by distillation or by processes that use membranes such as reverse osmosis . These processes use large amounts of energy.
What is waste water used for?
Lots of things at home like having a bath, going to the toilet , doing the washing up. When we flush it down the drain it goes to the sewers and towards sewage treatment plants
What do agricultural systems produce a lot off?
Waste water including jutrient run off fromfields and slurry from animal farms
What happens to water in sewers from domestic and agricultural sources?
It is treated to remove any organic matter and harmful microbes before it can be put back into fresh water sources like rivers or lakes. Otherwise it would make them very polluted and would pose health risks
What does industrial processes water waste contain aswll as organic matter?
Harmful chemicals , so it has to undergo additional stages of treatment before it is safe to release into the environment
Where does most waste water come from?
Urban lifestyles and industrials processes, sewage and agricultural waste.
What happens when sewage is treated?
- screening and grit removal
- sedimentation to produce sewage sludge (sinks to bottom)and effluent (rises to the top)
- anaerobic digestion of sewage sludge( breaks down sludge using bacteria, it releases methane gas)
- aerobic biological treatment of effluent
Sewage treatment vs fresh water treatment?
-sewage requires more processes than fresh water but uses less energy than desalinisation of salt water, so could be used in areas where there is not much fresh water
What is sustainable development?
Takes into account present society while not damaging lives of the future generations.
How is extracting resources unsustainable?
Dud to the amount of energy used and the waste produced. Processing the resources into useful materials such as glass or bricks , can be unsustainable too, as usually use energy from finite resources
How to reduce the use of finite resources?
People need to stop using the, , which also reduces energy and waste products from production. Chemists have developed ways of decreasing the use of finite materials, for example catalysts used to reduce the amount of energy required for certain processes
Is copper a finite resource?
Yes, all of the esrths resources of metal ores are limited
What are the two ways of extracting copper from low grade ores?
- phytoming
- bioleaching
What does phytomining and bioleaching help do?
Avoid traditional mining methods of digging , moving and disposing of large amounts of rock
What is phytomining?
Uses plants to absorb metal compounds. the plants are harvested and then burned to produce ash that contains metal compounds
What is bioleaching?
Uses bacteria to produce leachate solutions that contain metal compounds
How metal compounds can be processed to obtain metal?
Copper can be obtained from solutions of copper compounds by displacement using scrap iron or by electrolysis
Why is recycling metals important?
Mining and extracting metals takes a lot of energy most of which comes from burning fossil fuels. recycling uses less energy than is needed to mine and extract new metal . It also conserves finite amount of each metal and cuts down on landfill waste.
How are metals usually recycled?
By melting them and then casting them into the shape of the new product
How can recycling glass help the environment?
Reduces amount of energy needed to make new glass products and also waste created when glass is thrown away
How can glass be recycled?
- often be reshaped.
- others types of glass cant be reused so they’re recycled instead. Usually the glass is separated by colour and chemical composition before being recycled. The glass is then crushed and melted to be reshaped in glass products such as bottles or jars.
How does reduction in use , reuse and recycling help sustainability?
Limits use of limited resources , eneergy sources , waste and environmental impacts
Where do metals , glass , building materials , clay ceramics and most plastics come from?
Produce from limited raw materials. Much of the energy for the processes comes from limited raw materials. Obtaining raw materials from the earth by quarrying and mining causes environmental impacts
What does the amount of separation of a metal depend on?
On the material and the properties reauired of the final product. For example, some scrap steel can be added to iron from a blast furnace to reduce the amount of iron that needs to be extracted
from iron ore.
What are the stages of the life cycle?
- Getting raw materials
- Manufacture and packaging
- Using the product
- Product disposal
What is the life cycle assessment?
Looking at every stage of a products life tos ee how it damages the environment.
Plastic bag LCA?
Raw materials: crude oil
Manufacturing and packaging: compounds needed to make the plastic are extracted from crude oil by fractional distillation , followed by cracking and then polymerisation . Waste is reduced as the other fractions of crude oil have other uses
Using the product: can be reused. Can be used for other things like shopping, eg. Bin liners
Product disposal: recycleable but not biodegradable and will take up space at a landfill and pollute land
Paper ba LCA?
Raw materials: timber
Manufacturing and packaging: pulped timber is processed using lots of energy. Lots of waste is made .
Using the product: usually only one use
Product disposal: biodegradeable, non toxic and can be recycled
Problem with LCA?
Selective LCAs can be devissed to evalute a product but these can be misused to reach pre determined conclusions
