Using Resources Flashcards
what do humans use the earths resources for
to provide warmth, shelter, food and transport
what do natural resources provide
food
timber
clothing
fuels
why are finite resources from the earth, oceans and atmosphere processed
to provide energy and materials
what does chemistry play an important role in
improving agricultural and industrial processes to provide new products
sustainable development
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 renewable energy resources
sources of power that quickly replenish themselves and can be used again
only includes plants or wood if they continue to be replanted
what are finite resources
resources with a limited supply that will eventually run out
what is potable water
water of a suitable quality which is essential for life so is safe to drink
what does water need for humans
sufficiently low amounts of dissolved salts and microbes
potable water production process
1 filtered so leaves stones and large material is removed
2 water moves and only sediment settles at the bottom of the tank
3 add aluminium sulphate making the particles clump together and settles at the bottom
4 water is passed through fine sand and gravel to remove more particles
5 sterilisation occurs to kill microbes using chlorine or uv light
6 check the ph and adjust it if needed
how do you purify salty water
desalination
desalination by distillation
1- salty water is evaporated as sea water is heated
2- water is cooled and condensed
3- salt is left in the first tank
4- creates pure freshwater
desalination by reverse osmosis
1-using high pressure, salty water is forced through a semi permeable membrane
2- the salt is removed and the water moves through
disadvantages of desalination
both methods are very expensive
sewage water treatment process
1 sewage arrives to the pumping station and large objects are filtered from the water through a mesh screen
2- primary sedimentation -large paddles swirl the water and solids sink and are collected at the bottom
3- biological treatment- bacteria feed aerobically on organic matter and kill harmful bacteria
4- secondary sedimentation- good bacteria are removed here
5- water is sterilised using chlorine, ozone or uv light
6- it is pumped into seas and rivers
7- waste is digested by anaerobic respiration in a biogas tank
what is the sewage leftover used for
fertiliser
biogas
solid fuel
landfill sites
to generate electricity
where is it cheapest and easiest to obtain potable water from
groundwater
wastewater
when is seawater easier to obtain potable water
for countries with little fresh water
production of biogases in a biogas tank
1 sewage waste containing organic matter goes into the slurry
2 carried out at temp between 35 and 55 degrees
3 in the digester microorganisms will respire anaerobically to produce biogas
4 any solid matter left is pumped out of the outlet and used as fertiliser
why are life cycle assessments carried out
to assess the environmental impact of a product through all stages of its life
what are the stages of the life cycle assessment
raw materials
manufacture
distribution
product use
disposal of the product
what does the raw materials stage of the LCA deduce
are they renewable/non renewable
where are they found
how far do they need to be transported
what does the manufacturing stage of the LCA deduce
what processes are needed for manufacture of the materials and the product
what does the distribution stage of the LCA deduce
the environmental impacts of transporting the product
how far it has to be transported