The Earth’s Resources

Question 1

Finite resources

Answer 1

Being used up at a faster rate than they can be replaced

Eventually run out

Question 2

Raw materials used for

Answer 2

Metal ores = (used to ) extract metals
Crude oil = make polymers and petrochemicals, petrol, diesel, kerosene (used in transport)
Limestone = cement and concrete

Question 3

Examples of renewable sources

Answer 3

Plastics made from polymers made from ethene which can be produced from ethanol
Wood made form trees

Question 4

Collecting fresh water

Answer 4

Rainwater seeps down through soil and rocks to aquifers

Drill and pipe down to form water well in aquifers

Question 5

What happens to the gases that rainwater dissolves?

Answer 5

Air falls onto ground
Comes in contact with land
Dissolve soluble substances as it passes over them
Water from natural sources contain dissolved minerals and microorganisms from soil and decaying matter
Unsafe

Question 6

Making water safe to drink

Answer 6

Passing untreated water through filter beds made of sand and gravel to remove solid particles
AND
Adding chlorine to sterilise water killing microorganisms OR passing ultra-violet light through water

Question 7

Purifying salty water

Answer 7

Rains
In drier climates use seawater or salty water from marshes
Distilling seawater = expensive, energy costs
Converting salty water called desalination
Desalination used in oil-rich nations and island with no natural sources of water
Uses less energy
Energy is still needed

Question 8

Sewage treatment

Answer 8

1) Screening = remove large solid objects
2) Primary treatment = solid sediments settle down from mixture. Large paddles rotate and push solids towards centre of tank. Watery liquid above sludge flows into next tank
3) Secondary treatment = break down microorganisms, tank is aerated by bubbling air through waste water
4) Final treatment = useful bacteria settle out at bottom of bank as sediment, sediment recycled or passed into sludge
4) Waste water safe to put back into rivers

Question 9

Treating sewage sludge

Answer 9

Sludge dried and used as fertiliser = improve soil or used as renewable energy
Organic matter = digested a aerobically by microorganisms
Biological treatment = high temperatures, speeds up breakdown of organic matter
Breakdown products = biogas which is burned to power sewage treatment plant or provide electricity

Question 10

2 methods to obtain copper metal from ore

Answer 10

Sulfuric acid produce copper sulfate solution before extracting copper
Smelting, copper ore is heated to produce impure copper
Smelting and purifying copper ore uses huge amount of energy and electricity = pollution

Question 11

Extracting copper from malachite

Answer 11

1) Put iron nail into copper sulfate solution
OR
2) Collect copper sulfate and place in beaker. Set up circuit (electrolysis) and turn p=owner on, see copper metal collecting
Metal ions positively charged in electrolysis so produces pure copper

Question 12

Ionic equation for copper sulfate extraction

Answer 12

Fe(s) + Cu2+(aq) -> Fe2+(aq) + Cu(s)

Question 13

Photomining

Answer 13

1) Plants absorb copper ions grown in soil
2) Plants bunt and copper extracted from ash
3) Add sulfuric acid to ash
4) Copper ions dissolve
5) Use electrolysis

Question 14

Bioleaching

Answer 14

1) Bacteria feed on low-grade metal ores
2) Solution of copper ions obtained from waste copper ore
3) Scrap iron and electrolysis used to extract copper from leachate
Slow process

Question 15

What does the LCA do?

Answer 15

Asses impact on environment

Question 16

What do the LCA asses?

Answer 16

Getting and processing raw materials
Making product
Using, reusing and maintaining the product
Disposing of a product at end of useful life

Question 17

How is an LCA carried out by?

Answer 17

Listing all energy and material inputs and outputs into environment
Evaluating potential environmental impacts from these inputs and outputs
Interpreting results to help make decisions about using one material, process, product or service over another

Question 18

LCA summary

Answer 18

Raw material extraction -> manufacture -> use-reuse-maintenance -> recycle/waste management

Question 19

What is the aim of the “reduce, reuse and recycle” campaign?

Answer 19

To reduce:
Our use of limited resources
Our use of energy
The waste we used

Question 20

Recycling Alumnium

Answer 20

Important to recycle to help conserve the Earth’s reserves of aluminium ore
Extracted from molten aluminium oxide using electrolysis
Requires huge amount of energy
Recycling saves energy and money

Question 21

Recycling iron and steel

Answer 21

Saves energy to extract iron and turn it into steel
Energy supplied by burning fossil fuels
Natural gas used to heat air entering blast furnace
Recycling saves non-renewable fuels
Reduces pollution

Question 22

Recycling Copper

Answer 22

Difficult process
As copper is often alloyed
Copper must be purified for use
Recycle by melting or reusing

Question 23

Environmental considerations

Answer 23

Recycling reduces need to mind
Conserves metal ores
Prevents pollution
Quarrying destroys habitats
Ores are mined and processed to extract metals, smelting produces sulfur dioxide gas and escapes in air causing acid rain