Using Resources

Question 1

What do we use natural resources for

Answer 1

• warmth
• shelter
• food
• clothing

Question 2

Potable water

Answer 2

Go look through the chem deck

Question 3

What is a finite resource

Answer 3

One that will eventually run out
- coal, oil, gas

Question 4

Examples of renewable energy

Answer 4

• solar
• wind
• wave
• tidal
• geothermal

Question 5

What is potable water

Answer 5

Water that is safe to drink, but it still has some impurities in it

Question 6

What is pure water

Answer 6

• odourless
• tasteless
• colourless

-only contains H2O

Question 7

What does potable water contain low levels of in order to be safe

Answer 7

• microbes
• salts

Question 8

Why is making sea water safe to drink, harder than pond water

Answer 8

High energy cost for removing sodium chloride from the sea water

Question 9

How is potable water sterilised

Answer 9

• removing insoluble by passing the water through filter beds
• Microbes are killed via sterilising with:
  —> chlorine
  —> ozone
  —> ultra violet
• But you need to use the right amount of these as they can also be harmful to humans in excess

Question 10

What is desalination

Answer 10

• turning sea water into drinking water
• this can be done via distillation or reverse osmosis

Question 11

What is distillation

Answer 11

• heat sea water to boiling point and it evaporates
• steam rises, cools and condenses in a condensing tube
• leaving behind the salt

Question 12

What are the downsides to desalination

Answer 12

• high energy cost of boiling water and cooling down steam in tube
• not all water evaporates = leaves salty waste water = difficult to sustainable dispose of, without harming aquatic life

Question 13

What is reverse osmosis

Answer 13

• forcing water thru a membrane at high pressure
• the membranes tiny holes allows water through, but not ions and other molecules
• because they are too big

Question 14

What is the disadvantage of reverse osmosis

Answer 14

• produces lots of waste water = not very effective
• membranes are expensive

Question 15

What are the dangerous things in waste water

Answer 15

Pollutants:
- harmful bacteria
- nitrogen compounds

Question 16

What are the dangerous things in industrial/agricultural waste water

Answer 16

• high levels of toxic metal compounds
• fertilisers
• pesticides

Question 17

What are the different steps in cleaning sewage water

Answer 17

1. Screening: removes twigs, branches and other materials
2. Sedimentation: heavy solids sink to bottom of settlement tank (forming sludge), effluent stays above
3. Effluent undergoes biological aerobic digestion (by pumping air thru to encourage aerobic bacteria to break down organic matter and other microbes)
4. Sludge and other materials undergo anaerobic digestion: producing fertilisers and methane gas for fuel)

Question 18

How do you find the mass of a dissolved solid

Answer 18

Mass of evaporating basin before - mass of evaporating basin of solid left behind from evaporation

Question 19

What are the different stages to an LCA

Answer 19

• extracting and processing raw materials
• manufacturing and packaging product
• use of product
• disposal of product

Question 20

Describe stage 1 of LCA - extracting and processing raw materials

Answer 20

• Is it finite?
• expensive energy to extract, transport then process raw material?
• scar the landscape?
• waste products harmful to local ecosystems?

Question 21

Describe stage 2 of the LCA - manufacturing and packaging product

Answer 21

• it considers how much energy and resources are required
• energy is used in electricity, fuel, electricity
• is the pollution produced considered?
• what’s the environmental impact of transporting the goods from factory to customer?

Question 22

Describe stage 3 of the LCA - use of product in lifetime

Answer 22

Depends on product
- car has a large impact: uses fuel = finite resource = bad
- wooden chair has a relatively small impact: made from a renewable resource = good

Question 23

Describe stage 4 of the LCA - disposal of product

Answer 23

• landfill = high environmental impact
• incineration = low-ish environmental impact
• Recycling = good, no new compounds have been taken from environment

Question 24

What are the disadvantages of comparative LCAs

Answer 24

• opinion based: people may disagree
• companies producing the product are biased: may hide certain important details

Question 25

What are the advantages of recycling

Answer 25

• fewer resources needed = finite resource can stay in supply for longer
• less stuff in landfill
• no energy cost of extracting materials or processing them; they’re already there
• cheaper to recycle then to not = lower greenhouse gas emissions from producing a new product

Question 26

What are the disadvantages of recycling

Answer 26

• you have to transport it to be recycled = greenhouse emissions
• metals are difficult to sort = can effect purity of product = important for copper products

Question 27

Compare traditional mining methods with modern biological ones

Answer 27

• disadvantage: slow
• advantage: lower impact on landscape and environment

Question 28

What is phytominig

Answer 28

• plants absorb metal compounds found in soil
• plants can’t get rid of it, instead concentrate it in their leaves
• plants are harvested, burnt in a furnace to ash
• ash contains soluble metal compounds we want
• ash can then go through electrolysis or a displacement reaction in order to gain the wanted metal compounds

Question 29

What is bioleaching

Answer 29

• bacteria produce acidic solution called leachate: containing copper ions
• copper ions are then displaced out of the solution with iron

Question 30

Disadvantage of bioleaching

Answer 30

Produces toxic substances that are harmful to the environment