Using resources Flashcards
what do humans rely on and where does it come from?
relay on earth resource to provide them with food,shelter ,warmth and transport
all resources come from the earth crust,ocean and atmosphere which are renewable (timber ) or finite (metal ores)
How do humans care for the earth/What is agriculture?
they take care of it so the earth does become to polluted
as population increases human relay on agriculture
(the art and science of cultivating the soil, growing crops and raising livestock)to supplement or even replace such resources
What does water contain?
naturally contains microorganism and dissolved salts but in order for us to drink this we need them to be at low levels for it to be safe enough for us to drink
What is potable water?
water that is good quality and safe to drink
How is potable water produced?
1) fresh water from a suitable source (river,lake away from polluted areas is collected
2) it is passed through a filter bed to remove solid particles
What elements in group 7 is added to making potable water?
3) chlorine gas is added to kill harmful microorganism
4) fluoride is added to drinking water to reduce tooth decay
How can water be sterilized and how can the taste of water be improved?
Ozone and ultraviolet can also be used to sterilize water
to improve quality of water more dissolved substances can be removed by passing the water through a filter containing carbon ,silver and ion exchange resins
What is desalination?
can be done if fresh water supplies are limited to produce pure water
can be done by distillation or osmosis
both process are very expensive and use a lot of energy
What happens during distillation?
The water is boiled to produce steam
the steam is condensed to produce pure liquid water
How is large amounts of water wasted?
wasted by homes,agricultural process and industrial process
the waste must be treated before it can be released back in to the environment
What needs to be removed from sewage and agricultural and industrial waste water?
organic matter
harmful organisms
toxic chemicals
What does a sewage treatment include?
screening and grit removal
sedimentation to produce sewage sludge and effluent
anaerobic digestion of sewage sludge
aerobic biological treatment of effluent
Why is copper a useful metal?
it is a good conductor of electricity and heat
easily bent,yet hard enough to make waterpipes and tanks
does not react with water so long lasting
What is smelting?
when copper is extracted from copper-rich ores by heating the ores with a carbon furnace and then be purified by electrolysis
How can copper be obtained?
from solution of copper salt by electrolysis (positive copper ions move towards the negative electrode and form pure copper)
displacement using scrap irons
How can copper be extracted?
low grade ores
contaminated land by biological methods
What is phytomining and the process?
uses plant to absorb copper
as the plant grows they absorb and store copper
the plant is then burnt and the ash produced contains copper in relatively high quantities
What is bioleaching and the process?
uses bacteria to extract metals from low grade ores
a solution containing bacteria is mixed it a low grade ore
the bacteria converts the copper into a solution known as a leachate solution from which copper can easily be extracted
What is rusting?
metals corrode when they react with oxygen and water in the environment
the term rusting is when an iron object or object containing iron corrode
How can we prevent corrosion?
painting
electroplating
greasing a metal object to stop oxygen and water from reaching the surface and therefore stop corrosion from occurring
What is sacrificial protection?
more reactive metal is placed in contact with the metal
EG-blocks of the more reactive magnesium metal are attached to the iron or steel object
as magnesium is more reactive than iron it reacts and loses electrons instead of the iron
What is galvanising and the process?
used too protect iron or steel projects
the object is coated in a layer of zinc
the zinc layer stops oxygen and water from reaching the metal and stops the corrosion
if the surface of the zinc is scratched it does not matter the zinc provides sacrificial protection
How is aluminium protected from corrosion?
by a thin layer of aluminium oxide which acts as a barrier and prevents the aluminum from reacting further
What is glass?
non-crystalline solid
How is soda lime glass made?
made by heating a mixture of sand ,sodium carbonate and limestone and is used as window glass
How is borosilicate glass made?
made by heating sand and boron trioxide to a high temp than that used for producing soda-lime glass
used to make chemical glassware,cooking equipment and car headlights
How are pottery and bricks made?
clay ceramics
made by shaping wet clay and then heating them in a furnace
in the furnace water is removed and chemicals reaction take place that make the object retain is shape and become harder and stronger
What is a composite material?
consists of 2 materials with diff properties
the material are combined together to produce a material that has its own improved properties
EG concrete and fiberglass
What is the life cycle assessment?
used to assess the environmental impact a product has over its lifetime
provide a way of comparing several alternative products to see which one causes the least damage to the environment
What do scientist measure the impact of?
extracting raw materials processing raw materials manufacturing the product how the products is used how the product transported and disposed of at the end of its life
Why should we reuse and recycle as much as possible?
to save money and energy
make sure natural resources are not used up unnecessarily
reduce the amount of waste produced
How can glass,plastics and metals be recycled?
waste glass can be crushed,melted and reused
some waste plastics can be recycled to make fleece material
metals can be recycled by melting them down and then making them into new objects
What is the haber process?
used to manufacture ammonia which is used to produce nitrogen based fertilisers
What are the raw materials in the Haber process?
purified nitrogen-from the fractional distillation of liquid air
hydrogen-from natural gas or steam
What conditions is the nitrogen and hydrogen put under?
the nitrogen and hydrogen are passed over a iron catalyst at a modern temp (450) and at high pressures (200)
Describe the haber process
some hydrogen and nitrogen forms to make ammonia
because reaction is reversible some of the ammonia produced will break down again into nitrogen and hydrogen
on cooling the ammonia liquefies an can be removed from the mixture ]the unreacted nitrogen and hydrogen are recycled
Choosing conditions P1
the reaction between hydrogen and nitrogen is exothermic
high reaction temp faster rate or reaction but low yield of ammonia
low reaction temp ,high yield of ammonia,very slow reaction
Choosing condition P2
high pressure,high yield
iron catalyst increase ror
Why do w use fertilisers?
to replace the essential element in soil that are used by plants as they grow
plants absorb these chemicals in their roots so fertilizers must be soluble in water
to grow well plants need nitrogen phosphorus and potassium
What are NPK fertilisers?
contain compounds of all 3 elements
formulations of various salts that are mixed together to give appropriate percentage of each element
How many numbers does NPK fertilizers consist of?
3 numbers
1st % of nitrogen
2nd amount of phosphorus
3rd amount of potassium
Why is Ammonia used
alkaline gas that dissolves in water increase nitrogen content of soil can be oxidised to produce nitric acid neutralise nitric acid to produce ammonium nitrate fertilizer rich in nitrogen
Why are nitrogen based fertilizers important?
important chemicals because they increase the yield crops
Potassium chloride and potassium sulfate are soluble and can be used directly as fertilizers
Why is phosphate rock used?
high levels of phosphorus compounds
however they are insoluble so they cannot be used directly as fertilizers
How can phosphate rock be processed to make new useful products?
(nitric acid)
treated with nitric acid
to produce phosphoric acid and calcium nitrate
phosphoric acid is then neutralized with ammonia to produce ammonium phosphate
How can phosphate rock be processed to make new useful products?
(sulfuric acid)
treated with sulfuric acid to make single superphosphate-mixture of calcium phosphate and calcium sulfate
-can be reacted with phosphoric acid to make triple superphosphate
