Using Resources Flashcards
5 things humans use natural resources for
- energy and fuels for warmth
- building materials for shelter
- food through farming
- fuels for transport
- materials for clothing
define finite resource
Resource that can only be used once and is in limited supply.
define renewable resource
Resources which will not run out in the foreseeable future. This could be because the reserves of the resources is huge, or because the current rate of extraction is low.
describe the role chemistry plays in sustainable development
Chemists try to improve agriculture and industrial processes to provide new products that allow humans to meet their needs in a sustainable way.
what is sustainable development
Development that meets the needs of current generations without compromising the ability of future generations to meet their own needs.
state an example of natural products that are supplemented/ replaces by agricultural and synthetic products
until 1910 all fertilisers were obtained from natural resources such as manure. However, the Haber process enabled humans to produce fertilisers from nitrogen in the air, and has allowed synthetic fertilisers to be produced.
define potable water
Water that is safe to drink but is not pure water because it almost always contains dissolved impurities.
discuss importance of water quality on human life
Water is essential for life. The water they need has to be of good enough quality (potable), which for humans means it needs low levels of dissolved salts and microbes.
2 methods of desalinating salty water
distillation and reverse osmosis
how is distillation used to deslinate salty water?
- heat salt water
- when water reaches boiling point, it evaporates leaving the salt in the flask
- it will rise up and go down the condenser
- the condenser will lower the temperature so the pure water will condense
how is reverse osmosis used to desalinate salty water?
- Water is put under high pressure and passed through one side of a selectively permeable membrane to the other which has tiny pores in it.
- The pores allow water molecules through, but prevent most ions and molecules from passing through.
- The water is forced through from the more concentrated to more dilute side, leaving the salt
what is waste water a product of?
urban lifestyles and industrial processes that includes organic matter, harmful microbes and harmful chemicals.
describe the process of sewage treatment
- screening and grit removal to remove large particles
- sedimentation allows tiny particles to settle out from still water, which produces sewage sludge and effluent (the liquid which remains on top)
- the sewage sludge is digested anaerobically by specific bacteria
- the effluent is treated with aerobic bacteria to reduce the volume of solid waste
is it easier to obtain potable water from waste water or from ground/salt water?
waste water
2 alternative biological methods for extracting metals
phytomining and bioleaching
describe the process of phytomining
Plants absorb mineral ions through their roots. Phytomining (also known as phytoextraction) makes use of this:
1. plants are grown on a low-grade
ore
2. the plants absorb metal ions through their roots and concentrate these ions in their cells
3. the plants are harvested and burnt
4. the ash left behind contains metal
compounds
define bioleaching
Using bacteria to extract metals such as copper from their ores.
describe the process of bioleaching
- bacteria feed on the rock, turning insoluble copper compounds to soluble copper sulphate
- soluble copper sulphate is washed out and collected in a tank
- scrap iron is added so a displacement reaction can take place
- eventually, enough copper builds up in the tank to filter the contents and remove the metal
3 pos and 1 neg of phytomining
+ reduces the need to obtain new ore by mining
+ conserves limited supplies of high-grade ores
+ reduces the amount of rock waste that must be disposed of after traditional mining
- slow process
pos and neg of bioleaching
+ does not need high temperatures
- produces toxic substances, including sulfuric acid, which damage the environment
what are the 4 life cycle analysis (LCA) stages and what 2 things does each consider?
- extracting and processing raw materials
- what and where they come from
- how much energy’s needed to process them - manufacturing and packaging
- is the packaging sustainable?
- does it take lots of energy to make? - use and operation during its lifetime
- is it single use?
- how rubust it is - disposal at the end of its useful life (including transport and distribution at each stage)
- will it go to landfill?
- can it be recycled?
pos and neg of life cycle analysis
+ easy to work out accurate numerical values for parts of a LCA/ systematic
- but some parts of a LCA require judgements- not a totally objective process
life cycle analysis of a shopping bag made from plastic
- Raw materials- Crude oil is a finite resource; fractional distillation, cracking and polymerisation all require a lot of energy.
- Manufacture- Cheaper to make large quantities of bags from plastic.
- Use- Lower impact on the environment because plastic bags are usually stronger so they can be reused many times.
- Disposal Can sometimes be collected and recycled; if disposed of as litter, they do not biodegrade; in landfill, may take decades or centuries to degrade.