Chapter 14 - The Earth Resources Flashcards
Define ‘finite resources’
- Resources being used up at a faster rate than they can be replaced
- This means they will eventually run out being used at the current rate
- E.g fossil fuels
Define ‘renewable resources’
- Those that can be replaced at the same rate at which they are used up
- Crops to make biofuels
Example of a natural product and its use
- wool
- to make carpets, clothes
Example of agricutural product and its use
- cotton
- clothes, textiles
Example of a synthetic product, what it replaces and its use
- Nylon
- Replaces silk in clothes
2 examples of natural resources as raw materials to make new products
- Metal ores used to extract metals
- Limestone to make cement and concrete
Why are some predictions of finite resource usage not valid?
- They don’t build in the effect of recycling
Why are industries turning to renewable resources?
- Conserve finite resources
- Improve sustainability
Example of renawable resource?
- Polymers in the plastic industry
- Many use ethene made from ethanol
- Made by fermenting glucose from sugar cane or sugar beet
- More sustainable
What is the difference between potable and pure water?
- Potable is water that is fit to drink; which still can contain impurities or added minerals
- Pure water is drinkable; but doesn’t contain impurities or added minerals
Describe the process of treating ground water
- Water passes through a screen made of bars of metal. Catches large objects such as leaves and twigs
- Goes into a settlement tank; sand and soil out
- Aluminium Sulfate is added. Dirt clumps and forms sludge, dumped in landfill.
- Passed through sand and gravel. Removes mud or grit. Water is clean
- Chlorine added to remove bacteria. pH is checked and corrected
How is salt water purified?
Distillation, called desalination
What are the disadvantages and advantages of desalinating salt water
- Dis : Expensive
- Adv : Large Supply
Why is a shortage of water a problem for some hot countries even though they have coastlines?
No natural sources of water
Name another process besides distillation to purify salt water
Reverse osmosis
Describe how waste water is made safe to release into the enviornment
- Screening : Removes large objects and grit
- Primary Treatment : Solid sediment (sludge) leaves the mixture, as large paddles rotate and it is kept in a storage tank
- Secondary Treatment : Bacteria feed on harmful bacteria and microorganisms, breaking them down anerobically. Can take several hours/days
- Final treatment : Bacteria leaves the water. Chlorine sometimes used to sterlise. It is now safe to release into rivers/sea
Outline a concern of realeasing waste water into rivers
- Release of chlorine into rivers (which is added as a sterliser) is a concern
- Toxic organic compounds of chlorine can be formed
State two uses of sewage sludge
- Used as fertiliser on farmland
- Source of renewable energy
Describe a process used to treat sewage sludge
- Digested anerobically by micro organisms beneath the surface of a treatment tank
- Carried out at 35-55 degrees, higher temp is faster but requires more energy to heat
- Breakdown products include biogas, which can be burned to provide electricity.
- Sludge used as fertiliser or as a source of renewable energy
Suggest a method for testing the purity of salt water
