topic 10 resources Flashcards
what is portable water
water that has been treated or is naturally safe for humans to drink
what does pure water contain
H2O molecules
why isn’t portable water pure
because it contains lots of dissolved substances
what is the important thing to consider with portable water (3)
- that the levels of dissolved salts aren’t too high
- that it has a pH between 6.5 and 8.5
- there isn’t bacteria or microbes in the water
`what type of water is rainwater
``fresh water
what is fresh water
water that doesn’t have much dissolved in it
what are the 2 ways that water can collect as
surface water (in lakes,rivers or as groundwater (in rocks called aquifers)
what does surface water tend to usually do
dry up first
so where does the water come from for warmer places
groundwater
what are the 2 ways that freshwater can be treated by
- filtration
- sterilisation
how is filtration used to treat freshwater
a wire mesh screens out large twigs and then gravel and sand beds filter out any solid bits
how is sterilisation used to treat freshwater
the water is sterilised to kill any harmful bacteria or microbes. this can be done by bubbling chlorine gas through it or by using ozone or ultraviolet light
how is seawater treated in some very hot countries if there isn’t enough groundwater to provide portable water
by desalination
by what method can you test and purify a sample of water
by distillation
when you flush water where does the water go to
into the sewers and towards sewage treatment plants
what waste do agricultural systems produce
- nutrient run-off from fields
- slurry from animal farms
what must happen to sewage from domestic or agricultural sources and why
it has to be treated to remove any organic matter and harmful microbes before it is put back into freshwater sources like rivers
other than desalination, how else can seawater be treated
by a process that use membranes- reverse osmosis
how is seawater treated by membranes (steps)
-the salty water is passed through a MEMBRANE that only allows water molecules to pass through. Ions and larger molecules are TRAPPED by the membrane so separated from the water
why is distillation and reverse osmosis bad
-they require loads of energy so they are really expensive and are not practical for producing large quantities of fresh water
why is mining ores bad for the environment
because it uses loads of energy, scars the landscape, produces lots of waste and destroys habitats
2 examples of natural resources
cotton for clothing or oil for fuel
how can some natural products be replaced
by synthetic products or improved upon by man-made processes
how can rubber be extracted
by the sap of the tree
what can replace rubber
man-made polymers
what does agriculture provide
conditions where natural resources can be enhanced for our needs (development of fertilisers mean we can produce a high yield of crops)
2 examples of renewable energy resources
freshwater and food
what are finite resources
non-renewable resources
what are found in ores of the earth that makes them finite
minerals and metals
after being extracted, what do finite resources undergo
man-made processes to provide fuels and materials necessary for modern life (fractional distillation is used to provide fuels)
what is sustainable development
an approach to development that takes account of the needs of present society while not damaging the lives of future generations
why is extracting resources unsustainable
due to the amount of energy used and the waste produced
how is processing unsustainable
as it uses energy that is made from finite resources
how can we reduce the use of finite resources
- use less of it
- reduce the way it is produced
what have chemists developed in relation to using less finite resources
catalysts
what are catalysts used to do
reduce the amount of energy required for certain individual processes
how can we improve the sustainability of copper
by extracting it from low-grade ores (ores without much copper in)
what 2 low-grade methods are there for when extracting copper
- bioleaching
- phytomining
what is bioleaching
-bacteria are used to convert copper compounds in the ore into soluble copper compounds, separating out the copper from the ore in the process
what does the leachate (the solution produced by by bioleaching) contain
copper ions, which can be extracted
why is recycling metals good (3)
- uses much less energy than is needed to mine and extract new metal
- conserves the finite amount of each metal in the earth
- cuts down on the amount of waste getting sent to landfills
how are metals recycled
by melting them and then casting them into the shape of the new products
how can glass recycling help sustainability
by reducing the amount of energy needed to make new glass products and also the amount of waste created when used glass is thrown away.
how is glass separated before being recycled
by colour and chemical composition
how is glass reused (steps)
the glass is crushed and then melted to be reshaped for use in glass products
what does the life cycle assessment show about plastic bags
even though they are not “biodegradable”, they can take less energy to make and have a longer lifespan than paper bags so they are less harmful to the environment.
why are some LCAs bad
they may only show some of the impacts of a product on the environment and also be biased as they can be written to deliberately support the claims of the company
