Booklet 10 - Earths Resources Flashcards
What do humans use the earths resources for?
To provide warmth, shelter, food and transport
What do natural resources supply?
Natural resources supplemented by agriculture, provide food, timber clothing and fuels
Where are finite resources from? And what do they provide?
Finite resources are from the earth, oceans and atmosphere they’re processed to provide energy and materials
What is sustainable development?
Development that meets the needs of current generations without compromising the ability of future generations to meet their own needs
What does chemistry play an important role in?
In improving agricultural amd industrial processes to provide new products and in sustainable development
How can ethanol be replaced as it is being used up?
Polymers are usually made from alkenes, ethanol crops can be converted to ethene and used to make polymers, the crops can be replanted
How are wood chips be replaced as they’re being used up?
Fossil fuels are used in power stations to make electricity, however wood chip from trees can be used instead, and the trees replanted
What of what quality is needed for life?
Water of appropriate quality is essential for life
What should drinking water have?
They should have sufficiently low amounts of dissolved salts and microbes
What is potable water?
Water that is safe to drink
Why is potable water not pure?
In the chemical sense it isnt pure as it contains dissolved substances
What do methods to produce potable water depend on?
Available supplies of water and local conditions
In the uk, what does rain provide?
Provides water with low levels of dissolved water (fresh water) that collects in the ground and in lakes and rivers,
How is most potable water produced?
1) . Choosing an appropriate source of fresh water
2) . Passing the water through filter beds to filtrate any solid bits out
3) . Water is sterilised to kill any microbes and bacteria which can be done by bubbling chlorine gas through it or using ozone or ultraviolet light
What two things can you do if supplies of freshwater are low?
Desalination of salty water or sea water may be required
How can desalination be done?
1) . Distilation - seawater is heated until it boils, water molecules turn to steam leaving salt behind. Vapour is cooled and condensed
2) . Reverse osmosis - seawater is passed through a semipermeable membrane under pressure, water molecules pass through but dissolved substances don’t
What do urban lifestyle and industrial processes produce?
Large amounts of waste water that require treatment before being released into the environment
What do sewage and agricultural waste water require?
Removal of organic matter and harmful microbes
What does industrial waste water require?
Removal of organic matter and harmful microbes
What is the process of sewage treatment?
1) . Sewage is screened to remove any large bits of material and grit
2) . It undergoes sedimentation- heavier suspended solids sink to the bottem to make sludge while lighter effluent floats on the top
3) . Sludge from the bottme is removed and transferred into larger tanks where its broken down by bacteria in anaerobic digestion
4) . Effluent in the tank is removed and treated by aerobic biological treatment
What is the order of relative ease of obtaining potable water?
1) . Rainwater collection in lakes and reservoirs
2) . Desalination by distillation or reverse osmosis
3) . Waste water treatment
What type of the Earth’s materials are becoming limited?
Metal ores
What are copper ores?
They are becoming scarce and new ways of extracting copper low-grade ores
What do phytomining and bioleaching methods do?
They avoid traditional methods of digging, moving and disposing of large amounts of rock
What is phytomining?
Uses plants to absorb metal compounds eg copper. The plants are harvested and then burned to produce ash that contains metal compounds
What can the metak compounds be processed to obtain?
The metal - rg copper can be obtained from solutions of copper compounds by displacement using scrap ion or by electrolysis
What is a life cycle assessment?
They are carried out to assess the environmental impact of products
What are the four stages in LCA?
1) . Extracting and processing raw materials- requires lots of energy
2) . Manufacturing and packaging - lots of energy needed
3) . Uses and operation during its lifetime - uses can damage environment
4) . Disposal at the end of its useful life, including transport and distribution at each stage
What can be easily quantified in LCA’s?
Use of water, energy sources, resources and production of some wastes
Why are LCA’s not purely objective processes?
Allocating numerical values to pollutant gases is less straightforward and requires value judgment
What can be devised instead of LCA’s to evaluate a product?
Selective or abbreviated LCA’s
- but they can be misused to reach predetermined conclusions, eg in support of claims for advertising purposes
What does the reduction in use, reuse and recycling of materials by end user reduce?
- reduces the use of limited resources
- uses of energy stores
- waste
- environmental impact
What products are produced from raw materials?
Metals, gloss, building materials, clay ceramics and most plastics.
Most of the energy for the process comes from limited resources
What does obtaining raw materials risks from the earth require?
Quarrying and mining which take lots of energy and cause environmental impacts
How can glass bottles be reused?
They can be crushed and melted to make different glass products.
- other products cannot be reused and so are recycled for a different use
How can metals be recycled?
By melting and recasting or reforming into different products
What does the amount of separation depend on?
On the material and the properties required of the final product
