C14: Earth's Resources Flashcards

1
Q

renewable energy?

A

sources of power that can be replenished/used again
e.g timber

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

finite resources?

A

have limited supply that will eventually run out
e.g metal ores/minerals from earth’s crust

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

potable water?

A

water that is safe to drink (not pure, bc contains dissolved substances)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

how to obtain potable water?

A
  1. suitable fresh water source chosen
  2. filtration : water is passed through filter beds to remove different sized insoluble solids
  3. sterilisation: UV light/Ozone/Chlorine kill microbes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is desalination and process?

A

involves treatment of sea water to remove salt by distillation or reverse osmosis

reverse osmosis: Salt water put through partially permeable membrane.
- Only water molecules can pass through it, as membrane stops larger molecules passing

concentrated –> dilute

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

why is desalination not ideal when producing large quantities of fresh water?

A

expensive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

sewage treatment process?

A

Screening/grit removal : remove large materials (e.g plastic bags/twigs/grit) by screening
Sedimentation: water in a tank –> heavier solids sink to bottom (sewage sludge)
- lighter material (effluent) floats to top

Aerobic Digestion : effluent removed/treated by aerobic digestion to reduce volume of solid waste (digestion breaks down organic matter/bacteria)
Anaerobic Digestion : anaerobic digestion of sewage sludge - releases methane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

why is phytomining/bioleaching needed?

A

some metal ores are becoming scarce (copper/nickel ores)
- to extract these metals from low grade ores , phytomining/bioleaching is needed to meet GLOBAL DEMAND

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How is phytomining/bioleaching better for envrionment?

A
  • avoids envrionmental damage by avoiding traditional ways of mining (digging, moving and disposing large amounts of rock)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is phytomining?

A
  • uses plants to absorb metal compounds
  • plants are harvested/burned to produce ASH dissolved in acid that contains metal compounds
  • these are processed to obtain metal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is bioleaching?

A
  • uses bacteria to separate metal from ore
  • to form acidic solutions containing metal compounds - leachate
  • compounds can be reduced to solid metal form / extracted by displacement or electrolysis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is life cycle assessment?

A

carried out to assess envrionemntal impact of products in each of these stages :
- extracting/processing raw materials
- manufacturing/packing
- use and operation in lifetime
- disposal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

why is LCA subjective?

A
  • some stages are more diffiuclt to allocate numerical value to
  • have to make a judgement
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

how are selective/abbreviated LCAs misused?

A
  • can be used to advertise product (DONT GIVE COMPLETE PICTURE)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How are glass botles reused?

A
  • can be crushed/melted to make different glass products
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

how are metals recyled?

A

by melting/recasting or reforming into different product

17
Q

how are deposits of natural gas formed?

A
  • plankton living in ocean died/sunk
  • remains are covered by sediment
  • and subjected to high temps/high pressure –> forms natural gas