Chapter 14 Flashcards
what are the two ways of classifying natural resources?
renewable or finite
what are finite resources?
ones that are being used up faster than they can be produced
example of finite resources 4
crude oil
limestone
metal ores
fossil fuels
what are renewable resources?
ones that are being produced at the same rate they are being used up
example of renewable resources
crops used to make biofuels
advantages of mining metal ores 3
useful products can be made
provides jobs for people
brings money into the area
main disadvantage of mining metal ores 4
uses loads of energy
scars landscape
destroys habitats
lots of waste
how are crops used in polymerisation?
ethene can be made from ethanol which can be made from fermenting sugar cane or sugar beet
what are natural resources?
ones that form without human input from earth, sea, land and air
why are renewable resources now being used?
sustainability - we must preserve the earth for future generations
what is limestone used for?
to make cement and concrete
what is the aim of the reuse, reduce, recycle campaign?
to reduce our waste, energy usage and use of limited resources
why are ceramics fit for purpose? 3
insulators of heat
brittle
stiff
why are polymers fit for purpose? 3
insulators
flexible
easily moulded
why are metals fit for purpose? 3
malleable
good conductors
ductile
what is potable water?
water that is safe to drink
what are the 3 characteristics of safe water
low levels of dissolved salts
pH between 6.5 and 8.5
no bacteria
examples of uses of water 4
drinking
solvent
coolant
washing
process of collecting water from rain?
rainwater falls to ground
collects as surface water in reservoirs or percolates through the ground into aquifers (rocks which trap water underground)
why does rainwater need to be cleaned before drinking?
it dissolves some gases in the air as it falls
when in contact with land, it will dissolve soluble materials too
what are the two ways in which water is treated and why?
filtration - to remove large solids
sterilisation - kills harmful microbes
how is water sterilised?
addition of chlorine or using ultraviolet light or ozone
when do countries need to drink salt water?
when there isn’t enough rain
how to make salt water safe to drink?
distillation
how to distil salt water
heat
the water will boil and form steam, leaving salt crystals below
the steam will condense into water in the condenser
how is reverse osmosis used to distil salty water?
the water is passed through a membrane which only allows water molecules to pass through
process of cleaning water
passes through mesh to catch large objects as it enters water treatment works
enters settlement tank - sand and soil settle out
aluminium sulfate and lime added to water
passes through fine mesh to remove any remaining particles of mud or silt
chlorine is added to sterilise
pH of water checked to ensure it is neutral
stored in tanks and distributed to consumers
process of treating sewage
- screening - passes through mesh to remove large solids
- moved to settlement tank - solid sediment is allowed to settle whilst liquid sits on top and flows into next tank
- air is pumped into the tank to encourage bacteria to break down any harmful, organic matter in it
- the useful bacteria settle as sediment, where it is removed and recycled
what is the effluent in water treatment?
the water liquid above the sludge
sources of waste water 3
the Haber process
agricultural systems
homes
what happens to the sludge produced when treating sewage?
microorganisms anaerobically digest the organic matter
methane gas and biogas are produced
what is the methane produced from anaerobic digestion used for?
energy source
what is sludge from sewage treatment used for?
fertilisers
what is the biogas produced from anaerobic digestion used for?
energy source
what is a Life cycle assessment?
it looks at every stage of a product’s life and assesses its impact on the environment
where does copper come from
copper ores
what are the two main methods of extracting copper from the core?
sulfuric acid is mixed with the ore to create copper sulfate before the copper metal is extracted
smelting - copper ore is heated to a high temperature with air to produce impure copper
what are the four stages of a products’ life that has an effect on the environment that a life cycle assessment looks at?
getting raw materials
manufacture and packaging
using the product
product disposal
how is a life cycle assessment carried out? 2
looks at all the main energy and material inputs
the environmental impact of inputs and outputs
examples of outputs of a life Cycle Assessment that impact the environment 3
emissions
energy dissipation
waste
how can sourcing raw materials for a product impact the environment? 2
extraction leads to pollution
raw materials need to be processed which uses a lot of energy
how can manufacturing and packaging a product have an impact on the environment? 2
uses a lot of energy
waste chemicals from manufacturing pollute environment
how can using a product impact the environment? 2
the purpose of the product can impact the environment, for example fossil fuels being burnt or fertilisers leaching chemicals into streams
the longer a product is used for, the more energy needed
how can the way in which a product is disposed impact the environment? 3
often left in landfill sites- pollutes land and water
products might be incinerated (air pollution)
energy is used to transport waste to landfill = energy
problems with LCAs? 2
selective LCAs which only show some information may be biased to make a company look better
producing an LSA is subjective as it is the person’s own opinions about how important an issue is/the impact an issue has that are published
don’t take into account cost or performance
what is sustainable development?
an approach to development that ensures the needs of present society are met whilst preserving earth for future generations
what are the aims of the reduce, reuse recycle campaign? 3
to reduce our use of limited resources
to reduce the waste we produce
to reduce our use of energy
why is it important to recycle metals?
mining and extracting metals takes a lot of energy - produced by fossil fuels
recycling uses much less energy and is therefore cheaper
how is aluminium sourced?
extracting from aluminium oxide at high temperatures by electrolysis
how are metals recycled?
they are melted down and cast in the shape of the new product
why is extracting iron so bad
most of the energy needed comes from burning fossil fuels
what is a blast furnace used for?
extracts iron from its ore at a high temperature using carbon
why is the recycling of copper often more difficult?
it is often alloyed with other metals, eg zinc to make brass
how can recycling glass help sustainability?
reduces the amount of energy needed to make new glass
reduces the waste created when glass is thrown away
why are glass bottles especially easy to recycle?
they can often be reused without reshaping
process of recycling glass
separated by colour and chemical composition
glass is crushed and melted
it is then reshaped for use in new glass products
3 benefits of recycling metals
conserves limited supply of metal ores
reduces energy/pollution when creating metal
reduces waste
problems with mining 3
huge pits are left behind that scar the landscape
destroy habitats
groundwater can become acidic
what greenhouse gas is released in the extraction of iron?
CO2
one way in which chemists have helped sustainability?
catalysts reduce the amount of energy required for certain industrial processes
what is thermal decomposition?
when the bonds in reactants break because they are being exposed to high temperatures
describe the main process used to maintain pure copper?
copper ore is mined
copper ore is smelted (heated to a high temperature in air which produces impure copper)
impure copper is used as positive electrode in electrolysis
3 main problems of smelting copper
uses huge amounts of energy and electricity -
expensive
pollution of environment
why is electrolysis used to produce pure copper from impure copper?
impure copper used as positive electrode
metal ions are always positively charged
therefore they are attracted to and deposited at the negative electrode
half equation for the electrolysis of copper at the positive electrode?
Cu (s) -> Cu2+ (aq) +2e-
what happens at the negative electrode in the electrolysis of copper?
oxidation
what happens at the positive electrode in the electrolysis of copper?
reduction
half equation for the electrolysis of copper at the negative electrode?
Cu2+ (aq) + 2e- -> Cu(s)
how can iron be used to extract copper from copper sulfate solution?
iron displaces copper from its solutions
equation for iron + copper sulfate
iron + copper (II) sulfate -> iron (II) sulfate + copper
ionic equation for iron + copper sulfate
Fe(s) + Cu2+ (aq) ->Fe2+ (aq) +Cu (s)
what are the two new ways of extracting copper from LOW-GRADE ORES?
bioleaching
phytomining
process of phytomining
plants are grown in soil that contains copper
it builds up in leaves as plants can’t use it
plants are burned
copper extracted from copper compounds in ash
the copper ions can be leached by adding sulfuric acid
this makes a solution of copper sulfate
displacement by iron and then electrolysis = pure copper
process of bioleaching
bacteria feed on low-grade metal ores
they convert copper compounds in the ore into soluble copper compounds
the solution of copper ions produced (leachate) can be used in a displacement reaction with iron, then electrolysis to produce pure copper metal
why is only 20% of copper currently created by bioleaching?
it is very slow
