C14 -the earths recourses

Question 1

what are natural resources classified as

Answer 1

Natural resources can be classified as finite and renewable

Question 2

what are finite resources

Answer 2

finite resources = those that are being used up at a faster rate than can be replaced

Question 3

what are renewable resources

Answer 3

renewable = those that can be replaced at the same rate that they are being used up at

Question 4

Examples of finite resources and there uses

Answer 4

Examples of finite resources:
1. fossil fuels = used as energy sources and to make polymers and petrochemicals
2. trees = used for wood
3. metal ores = used to extract metals
4. limestone = used to make cement and concrete

Question 5

what is potable water

Answer 5

potable water = water that is safe to drink

Question 6

what are aquifers

Answer 6

aquifer = underground sources of water

Question 7

what do natural sources of water tend to have

Answer 7

water from natural sources will contain dissolved minerals (salts), microorganisms from soil and decaying matter

Question 8

what are 3 ways to make water potable

Answer 8

passing untreated water through filter beads made of sand and gravel to remove sand particles

the addition of chlorine or ozone which sterilises the water by killing microorganisms

passing UV light through the water also sterilises the water by killing microorganisms

Question 9

how can seawater from marshes be purified

Answer 9

seawater or salty water from marshes can be purified by using distillation –> BUT it’s an expensive process

Question 10

what is a disadvantage of normal distillation

Answer 10

it is expensive

Question 11

what is an alternative to normal distillation

Answer 11

flash distillation = in reduced pressure, water boils at a lot less than 100 degrees Celsius so less energy is needed to evaporate it, so it is easier and cheaper to distill

Question 12

what is desalination

Answer 12

desalination = converting salty water to potable, usable water

Question 13

explain reverse osmosis

Answer 13

reverse osmosis = uses membranes to separate water and the salts dissolved in it
there is no heating so this uses less energy than distillation
energy is still needed to pressurise the water passing through

Question 14

what is the problem with reverse osmosis

Answer 14

A problem with reverse osmosis is the corrosion of the pumps caused by salty water

Question 15

PRACTICAL: analysis and purification of water samples

Answer 15

test the pH of a salty sample given by teacher

teacher will give another sample - desalinate by distillation

test half the sample by distilled water collected for pure water by measuring its boiling water - pure water boils at 100 degrees celsius

test the pH of the othr hald of the distilled water sample

Question 16

why do we have to boil water instead of using other methods

Answer 16

u have to use these testing methods and not a test for water as those tests will only show the presence of water, not if it is pure or not

Question 17

what is sewage

Answer 17

sewage = is the collective term for all waste water that drains into large sewer pipes

Question 18

what is the first step in sewage treatment

Answer 18

screening - sewage passes through a grid that traps large objects and grit from the rest of the waste water

Question 19

what are the steps in primary treatment

Answer 19

Primary Treatment:
in the first circular tank, solid sediments are allowed to settle out from mixture

large paddles rotate and push solids (called sludges) to the centre –> piped to a storage tank for further treatment

the watery liquid (effluent) flows into the next tank containing many potentially harmdul microorganisms

Question 20

what are the steps in secondary treatment

Answer 20

Secondary Treatment:
In the second tank, useful bacteria feed on the remaining organic matter and microorganisms by breaking them down aerobically

tank is aerated by bubbling air through wastewater –> takes from hours to days depending on the quality of water, size of tank, rate of aeration and temperature
sludge is anaerobically digested

Question 21

what are the steps in the final treatment

Answer 21

Final Treatment:
in the last tank, bacteria settles at the bottom as sediment –> recycled back into the tank or passed into the tank where sludge is treated

Treated water is safe enough to be discharged back into rivers

If a river is a particularly sensitive ecosystem, water can be filtered be more time through a bed of sand, or sterilised using UV light or chlorine

Question 22

what are the concerns with using chlorine in water treatment

Answer 22

chlorine used is a concern as toxic organic compounds of chlorine can be formed in the environment

Question 23

what is a use of sludge

Answer 23

after further treatment, sludge can be used as fertilisers on farms or as renewable energy

Question 24

what does sludge contain and how is it broken down

Answer 24

sludge contains organic matter(human waste), suspended solids, water, and dissolved compounds
it’s digested anaerobically by microorganisms at the bottom of the tank

Question 25

how can biological treatment be sped up

Answer 25

biological treatment can be carried out at 35-55 degrees celsius to speed up the process

Question 26

what can we do with the breakdown of biological treatment products (name them)

Answer 26

breakdown products can include biogas which can be burned
or sludge can be dried out to make a crusty, solid cake which can be burned

Question 27

what can impure copper be used for

Answer 27

impure copper can be used as a positive electrode in electrolysis to make pure copper

Question 28

name two ways that we can obtain copper metal from the ore

Answer 28

two main methods used to obtain copper metal from the ore:
sulfuric acid - used to produce copper sulfate solution before extracting the copper metal
smelting (roasting) = copper ore is heated in a furnace with air to produce impure copper

Question 29

explain phytomining

Answer 29

phytomining = plants that can absorb copper ions are grown on soil containing low grade copper ore

plants are then burnt and copper is extracted from copper compounds in the soil

copper ions can be dissolved from ash by adding sulfuric acid

Question 30

explain bioleaching

Answer 30

bioleaching.= bacteria feed on low-grade metal ores - by a combination of biological and chemical processes a solution of copper

ions (leachate) can be obtained from waste copper ore - scrap iron and electrolysis are used to extract the copper from the leachate

Question 31

what 4 things does the LCA assess

Answer 31

The Life Cycle Assessment (LCA) is used to assess the impact on the environment caused by:
getting and processing the raw materials

making the product (and any packaging)

using, reusing and maintaining the product

disposing of a product at the end of its useful lif

Question 32

what is the LCA

Answer 32

The Life Cycle Assessment (LCA) is used to assess the impact on the environment

Question 33

How is the LCA assessed

Answer 33

An LCA is carried out by:
listing all the energy and material inputs and outputs into the environment

2. evaluating the potential environmental impacts of these inputs and outputs
3. interpreting results to help make decisions about one material, process, product or service over another

Question 34

summarise the stages of the LCA

Answer 34

the stages in a LCA can be summarised as:
raw material extracted –> manufacture –> use/reuse/maintenance –> recycle/waste management

Question 35

what are output LCAs

Answer 35

outputs in a LCA are: atmospheric emissions, waterborne wastes, and coproducts

Question 36

what is the aim of the Reduce,reuse, and recycle campaign

Answer 36

The aim of reduce, reuse and recycle campaigns are to reduce:
our use of limited resources
our use of energy
the waste we produce

Question 37

what are the benefits of the Reduce, reuse, and recycle campaign

Answer 37

recycling metals reduces the need to mine the metal ore
this prevents pollution problems from extractions and reduces habitats being destroyed by mining