C14 - The Earth's Resources Flashcards
Examples of finite resources
- Fossil fuels
- Metals
What is sustainable development
Development that meets the needs of current generations without compromising the ability of future generations to meet their own needs.
Examples of natural resources that are being replaced by synthetic ones
- Natural rubber —> synthetic rubber
- Manure as a fertiliser —-> ammonia fertilisers
Method for experiment to check if water is pure
- Get mass of empty evaporating basin
- Fill with water sample and place on a beaker of water on a tripod and gauze
- Heat until all water has evaporated
- Reweigh evaporating basin and if no change in mass, water was most likely pure
Method for experiment to purify water
- Heat water in conical flask on tripod and gauze
- Water will evaporate and travel along collecting tube
- When it gets to the cold beaker, it condenses and forms distilled water
Difference between potable water and pure water
Pure water - 100% H2O with no dissolved substances
Potable water - water safe to drink that has dissovled substances
How is potable water produced from fresh water
- Find a source of freh water e.g. a river or lake
- Pass water through filter beds to remove large insoluble particles and objects
- Water is then sterilised to remove microbes
Different substances that can be used to sterilise water
- Chlorine
- Ozone
- UV light
How is potable water produced from salty water
- Desalination - reduces levels of dissolved minerals to acceptable levels. This can be done through distillation (heating water)
- Water can be passed through membranes removing the ions (REVERSE OSMOSIS)
These both require lots of energy so are very expensive processes
Why is waste water treated
- Human waste has lots of harmful microorganisms and nitrogen
- Industrial waste could have toxic chemicals
- Agricultural waste could have harmful chemicals such as pesticides
Steps in waste water treatment
- Screening and grit removal - removes large objects
- Sedimentation in tanks - produces sewage sludge and liquid effluent and the sludge sinks to the bottom
- Sludge is taken away and digested by anaerobic bacteria
- Air with aerobic bacteria is bubbled through the effluent which digest organic molecules and microorganisms
Easiest and hardest ways to produce potable water
Easy - Ground water from aquifers which is then treated with chlorine
Hard - potable water from waste water, only done where water is scarce
How is the process of copper phytomining done
- Plants are grown on land with low-grade copper ore
- Plants absorb these and it gets concentrated in their tissue
- Plants are harvested and burnt
- Ash is dissolved in acid to produce a solution of a copper compound
How is the copper metal obtained from the compounds after phytomining or bioleaching
- Displaced using the addition of scrap iron as it is more reactive
- Electrolysis of the acid solution
Why is phytomining not widely used to extract copper
- High-grade copper ores are still available
- Not enough land available
- Phytomining takes a long time (slow process) and produces a low yield of copper
