C10 Flashcards
(46 cards)
What do we use resources for
We use recourses to provide
-warmth
-food
-shelter
-transport
How are resources produced
-Agriculture (eg Cotton
-scientists have replaced natural recourses with synthetic alternatives
(Eg crude oil rubber)
What is a finite recourse
Recourses that cannot be replaced as quickly as they are being used,they will run out
(Eg fossil fuels)
What is a renewable recourse
Recluses we can replace as quickly as we use them(will not run out )
Why is it important that human activities are sustainable
We can meet our needs without preventing future generations from meeting theirs
How does chemistry play an important role in how we use recourses
-artificial recourses allow us to grow more food with the land available
-helps us provide safe drinking water
What do processes such as phto mining and bio leaching help us do
Help us extract metals more efficiently
What does drinking water have to have for it to be able to be drunk
-low levels of dissolved salts
-cannot have high levels of microbes
What is water that is safe to drink called
Potable water
What is pure water
-water which contains no dissolved substances
What is pure water
Water which contains no dissolved substances at all
In the uk what is our main source of potable water
Rain water(low levels of dissolved substances)
What are good sources of fresh water
Aquifers,lakes,rivers an in reservoirs.
How do we produce potable water
-choose a fresh water source
-pass water through filter beds
-water is sterilised
How is potable water produced from salt water
-desalination
What is desalination
-reduced the levels of dissolved minerals down to an acceptable level for potable water
What ways is desalination carried out
-reverse osmosis (passing through membrane)
-distillation
-reduce the levels of dissolved minerals
What is the issue with desalination
-requires a large amount of energy which makes them very expensive
what does waste water contain
-organic molecules
-harmful microorganisms
how is waste water treated
-the sewage is screened by passing through mesh (removing solids and grit)
-sewage settles in large sedimentation tanks
(this produces a liquid effluent and a semi solid sludge which sinks)
-sludge is taken away by anaerobic bacteria
-in absence of oxygen bacteria produces biogas
-digested sludge can be used for fertilisers
what does liquid effluent contain
contains large amounts of organic molecules and harmful microorganisms
how is the molecules and bacteria in liquid effluent reduced
-air is bubbled through the liquid effluent allowing aerobic bacteria to multiply
-in the presence of oxygen the aerobic bacteria digest the organic molecules and harmful microorganisms
-now the liquid effluent can be safely discharges into nearby rivers or into the sea
what is water used for
-industry
-personal hygiene
how is water that is used in industry be treated
-remove harmful chemicals
-enter general sewage treatment