C10 Flashcards
What do humans use the Earth’s resources for?
- energy and fuels (warmth)
- materials for building
- food through farming
- fuels for transport
- materials for clothing
What is sustainable development?
Development that meets the needs of current generations without compromising the ability of future generations to meet their own needs
What are finite resources?
From the Earth’s crust, oceans and atmosphere and they will eventually run out
Give an example of a finite resource
- crude oil
- fossil fuels
What is potable water?
Water that is safe to drink.
(It has sufficiently low levels of dissolved salts, microbes and minerals)
How is potable water obtained in the UK?
rain provides water with low levels of dissolved substances (fresh water) that collects in the ground and in lakes and rivers
The potable water is collected by:
- choosing an appropriate source for fresh water
- passing the water through filter beds
- sterilising
What sterilising agents are used for potable water?
- chlorine
- UV light
- ozone
What happens when the supplies of freshwater are limited?
Desalination of sea/salty water
- can be done by distillation or processes which involve membranes e.g. reverse osmosis
- (requires high amounts of energy)
Explain what happens during reverse osmosis
1.water is put under high pressure and passes through a membrane with tiny pores in it
2.the pores allow water molecules to pass through but prevent most ions and other molecules from passing through
What are disadvantages of reverse osmosis?
-expensive membranes
-produces a large volume of waste water (low efficiency)
What does sewage treatment involve?
- screening and grit removal
- sedimentation, which produces sewage sludge and effluent
- anaerobic digestion of sewage sludge
- the (light) effluent is treated with aerobic bacteria to reduce the volume of solid waste
How does mining damage the environment?
- landscape scars
- pollution
- habitat destruction
What are new ways of extracting copper from low-grade ores?
- Phytomining
- Bioleaching
Properties of copper:
- malleable
- unreactive
- conducts heat and electricity well
Explain phytomining
Uses plants to absorb metal compounds from contaminated land. The plants are harvested and then burned to produce ash (containing the metal compound)
Explain bioleaching
Uses bacteria to produce leachate solutions that contain metal compounds
bacteria are added to low grade ores and they then form copper compound solutions called leachate solutions. The metal (copper) could then be processed/extracted by electrolysis or a displacement reaction with a more reactive metal (e.g. scrap iron)
What are life cycle assessments used for?
to asses the environmental impact of products in each of the stages
What are the stages of LCAs?
- extracting and processing of raw materials
- manufacturing and packaging
- use and operation (during its lifetime)
- disposal at the end of its useful life (including transport and distribution)
What is a disadvantage of quarrying/mining?
- damaging appearance the landscape
- loud and noisy
- loss of habitats
How can metals be recycled?
by melting and recasting or reforming into different products