Using resources Flashcards
(29 cards)
Why do humans use the Earth’s resources?
To provide warmth, shelter, food and transport
What is a finite resource?
Finite resources are those that are being used up at a faster rate than they can be replaced. So if we carry on using these resources at current rates, they will eventually run out.
Example: fossil fuels (coal, crude oil and natural gas).
What is a renewable resource?
Renewable resources are those that can be replaced at the same rate at which they are used up.
Examples: crops used to make biofuel
Where do natural resources come from and what do they provide?
* NB: You can classify natural resources as finite or renewable
Supplemented by: agriculture
Provides: food, timber, clothing and fuels
Where do finite resources come from and what do they provide?
Come from: Earth, oceans and atmosphere
Provide: energy and materials
How does chemistry play an important role in the usage of Earth’s resources?
Chemistry plays an important role in:
- improving agricultural and industrial processes to provide new products
- sustainable devlopment, which is development that meets the needs of current generations without compromising the ability of future generations to meet their own needs
What are examples of natural products, their uses, and their alternative synthetic products?
Wool
Use - clothes, carpets
Alt. product - acrylic fibre (polyacrylonitrile); poly(propene)
Cotton
Use - clothes, textiles
Alt - polyester
Silk
Use - clothes
Alt - nylon
Linseed oil
Use - Paint
Alt - acrylic resin
Rubber
Use - tyres; washers
Alt - various synthetic polmers, e.g. poly(butadiene)
Wood
Use - Construction
Alt - PVC, composites (MDF)
What are examples of finite resources?
- metal ores used to extract metals
- crude oil used to make polymers and petrochemicals
- limestone used to make cement and concrete
- crude oil to make the petrol, diesel and kerosene we use for transport
What are examples of renewable resources?
- ethene used for polymers made from ethanol by fermenting glucose instead of deriving it from crude oil
- using wood chips to fuel power stations instead of fossil fuels, linked to a tree planting programme
Why is water important and what qualities should it have for humans?
Water of appropriate quality is essential for life.
For humans, drinking water should have sufficiently low levels of dissolved salts and microbes
What is potable water and what does the method of producing this water depend on?
Potable water is water that is safe to drink.
The methods used to producing potable water depends on available supplies of water and local conditions.
True or false - is potable water the same as pure water?
FALSE - potable water is not pure water in the chemical sense because it contains dissolved substances
Why is starting with fresh water easier than sea water in the method to produce potable water?
Removing the large amount of sodium chloride present in sea water requires a lot of energy
How is most fresh water provided in the UK?
In the UK, rain provides enough fresh water to meet the needs of the population. Sometimes during the summer montsh in some areas of the UK water reserves run low and people are encouraged to conserve tap water by teh use of hosepip bans.
Rainwater collects in rivers lakes and in rocks underground. This water contains low levels of dissolved substances.
In the United Kingdom (UK), rain provides water with low levels ofdissolved substances (fresh water) that collects in the ground and in lakes and rivers.
How is most potable water produced in the UK?
- Choosing an appropriate source of fresh water
- Passing the water through filter beds to remove insoluble particles
- Sterlising the water to kill microbes
What are the methdos used for sterilisation of water?
Chlorine
ozone
ultraviolet light
How is potable water produced if supplies of fresh water are limited? What are the two methods of achieveing this?
Desalination of salty water or sea water may be required, if supplies of fresh water are limited
Desalination can be done by:
- distillation
- processes that use membranes such as reverse osmosises.
These processes require large amounts of energy.
What is desalination?
The removal of salt from water. It is an energy-intensive process.
What are some of the advantages and disadvantages of distillation as a process to purify salty water?
Adv
- (desalination plants) Used in Middle East and some oil-rich nations and some islands with no natural sources of water apart from occasional, insufficient rainwater
- Under reduced pressure, water boils below 100 degrees, saving some of the eneryg costs by distilling salty water in a desalination plant
Dis
- Expensive process of purifying water by distillation
- High energy costs are involved in boiling large volumes of water
What are some advantages and disadvantages of using reverse osmosis as a desalinaton technique?
Uses membranes to separate the water and salts dissolved in it
Adv
- Can remove 98% of dissolved salts from seawater
- No heating involved, so uses less energy than distillation
Dis
- Energy is still needed to pressurise the water passing through
- Corrosion of pumps by salty water is also a problem
Describe in detail the process of producing potable water in the UK (from freshwater).
- (From reservoir) As the water enters the treatment works, it passes through screens. These catch large objects such as leaves and twigs.
1b. Settlement tank, for sand and soil to settle out - Aluminium sulphate and lime are added to the water. Small particles of dirt clump together so that they sink to the bottom of the water. This is dumped in a landfill site, where it forms mud.
- The water is passed through a special filter made of find sand and gravel. This removes any mud or grit, so the water is clean.
- The water may still contain harmful bacteria. A small amount of chlorine is added to the water ot kill any bacteria. Alternatively, ozone can be added or UV light can be used.
- The pH of water is checked and corrected so that it is neutral. It is then stored ready to be pumped to homes, schools, offices, and factories.
Why is waste water treatment needed?
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?
What does industrial waste water require?
Sewage and agricultural waste water require removal of organic matter and harmful microbes.
Industrial waste water may require removal of organic matter and harmful chemicals.
What are the four main stages of sewage treatment?
- screening and grit removal
- sedimentation to produce sewage sludge and effluent
- anaerobic digestion of sewage sludge
- aerobic biological treatment of effluent
