C10 - Using Resources Flashcards
How do humans use the Earth’s resources (4)
To provide warmth, shelter, food and transport
What do natural resources, supplemented by agriculture provide (4)
- Food
- Timber
- Clothing
- Fuels
What are finite resources from the earth, oceans and atmosphere processed to provide (2)
- Energy
* Materials
What does chemistry play an important role in
Chemistry places an important role in improving agriculture and industrial processes to provide new products and in sustainable development
What is Sustainable development
Is development that meets the needs of current generations without compromising the ability of future generations to meet their own needs
Examples of natural products that are replaced by agricultural and synthetic products
Rubber is a natural product that can be extracted from tree sap - however man-made polymers have now been made which can replace rubber in uses such as tyres
Finite resources
Aren’t formed quickly enough to be considered replaceable e.g fossil fuels and nuclear fuels
Renewable resources
Reform at a similar rate to, or faster than, we use them e.g timber
Orders of magnitude to evaluate the significance of data
Check photos
Water of appropriate quality
- Is essential for human life
* e.g for humans, drinking water should have sufficiently low levels of dissolved salts and microbes
Potable water (2)
- Is water that is safe to drink
* Is not pure water in the chemical sense because it contains dissolved substances
What do the methods used 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 substances (fresh water) that collects in the ground and in lakes and rivers
How is most potable water produced (3)
- Choosing an appropriate source of fresh water
- Passing the water through filter beds
- Sterilising
Sterilising agents (2)
- chlorine
* Ozone or ultraviolet light
What happens if supplies of fresh water are limited
Desalination of salty water or sea water may be required
How can desalination be done?
Decentralisation can be done by distillation or processes that use membranes such as reverse osmosis (These processes require large amounts of energy)
Difference between potable water and pure water
Pure water only contains H2O molecules and potable water contains dissolved substances making it safe to drink
Difference in the treatment of ground water and salty water (2)
- Seawater contains too much dissolved salt to make it suitable as drinking water - However, pure water can be produced from seawater by simple distillation
- However, water produced by distillation is useful in the laboratory for dissolving substances
Water purification - required practical (apparatus) (6)
- Round bottomed flask
- Condenser
- Thermometer
- Salty water
- Bunsen burner
- Beaker
Water purification - required practical (method) (5)
- Test pH using a pH meter and make sure that it is neutral
- Set up the equipment (check photos)
- As the water in flask heats up and is evaporated and will enter the condenser as steam - condenses back into liquid due to temp drop
- Collect the water running out in a beaker
- Retest the pH of the water to check if it’s neutral
What do urban lifestyles and industrial processes produce
Large amounts of waste water that require treatment before being released into the environment
What does sewage and agricultural waste water require
Removal of organic matter and harmful microbes - industrial waste may require removal of organic matter and harmful chemicals
What do Sewage treatments include (4)
- Screening and grit removal
- Sedimentation to produce sewage sludge and effluent
- Anaerobic digestion of sewage sludge
- Aerobic biological treatment of effluent
Relative ease of obtaining potable water from waste, ground and salt water
Not very easy as it has to undergo additional stages of treatment before safe
Earth’s resources of metal ores
Are limited
Copper ores
Are becoming more scarce
new ways of extracting copper
from low-grade ores including Phytomining and bioleaching - these methods avoid traditional mining methods of digging, moving and disposing of large amounts of rock
Phytomining (2)
- Uses plants to absorb metal compounds
* The plants are harvested and then burned to produce ash that contains metal compounds
Bioleaching
Uses bacteria to produce leachate solutions that contain metal compounds
How can metal compounds be processed
To obtain the metal - e.g copper can be obtained from solutions of copper compounds by displacement using scrap iron or by electrolysis
Life cycle assessments (LCAs)
Are carried out to assess the environmental impact of products
Stages of life cycle assessments (LCAs)
- Extracting and processing raw materials
- Manufacturing and packaging
- Use and operation during its lifetime
- Disposal at the end of its useful life, including transport and distribution at each stage
What can be easily quantified
Use of water, resources, energy sources and production of some wastes
Why is LCA not a purely objective process
Allocating numerical values to pollutant effects is less straightforward and requires value judgements
How can selective or abbreviated LCAs be devised
To evaluate a product but these can be misused to reach pre-determined conclusions e,g in support of claims for advertising purposes
LCAs for shopping bags made from plastics and paper
Check photos
What reduces the use of limited resources
The reduction in use, reuse and recycling of materials by end users
What is produced from limited raw materials (5)
- Metals
- Glass
- Building materials
- Claw ceramics
- Most plastics
What does much of the energy for processes come from
Limited resources
What causes environmental impacts
Obtaining raw materials from the Earth by quarrying and mining
Glass bottles (2)
- Can be reused
* Can be crushed and melted to make different glass products
Metals
Can be recycled by melting and recasting or reforming into different products
What does the amount of separation required for recycling depend on
The material and the properties required of the final product e.g 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
