10a. Using Resources

Question 1

How have humans used the earths resources?

Answer 1

To provide warmth, shelter, food and transport

Question 2

List some renewable and finite resources

Answer 2

Renewable:
Wood, leather, cotton, solar power, ethanol (fermentation)

Finite:
Nuclear fuels, natural gas, metals, coal, oil

Question 3

List a modern and a historical version of the way humans obtain
- Warmth
- Shelter
- Food
- Transport

Answer 3

Warmth: Natural gas, fires (wood)
Shelter: Brick, mud/wood
Food: Plants/animals for both
Transport: Oil-cars(metal), horses

Question 4

What is sustainable development?

Answer 4

Development that meets the needs of current generations without compromising the ability of future generations to meet their own needs

Question 5

What is potable water?

Answer 5

Water that is safe to drink - it’s is not pure water in the chemical sense because it contains dissolved substances

Question 6

How can you check the purity of a substance?

Answer 6

Check the boiling or melting point if a substance as the pure version if the substance will always have a set melting or boiling point

Question 7

How is most potable water produced?

Answer 7

• Choosing an appropriate source of fresh water
• Passing water through filter beds to filter out insoluble substances
• Sterilising by adding ozone or chlorine or using UV light to kill microorganisms

Question 8

How does ozone sterilise water?

Answer 8

Ozone is a strong oxidiser that instantly kills bacteria, viruses and parasites
It is stronger than chlorine
It doesn’t leave an odour or chemical residue

Question 9

How does chlorine sterilise water?

Answer 9

Adding chlorine to water kills microorganisms in less than a minute
It is one of the most widely used disinfectants

Question 10

How does UV light sterilise water?

Answer 10

UV light emitters can be placed around pipes to kill microorganisms
Uses a lot of electricity

Question 11

How can you create potable water from sea water? (Short answer)

Answer 11

Desalination by either distillation or reverse osmosis

Question 12

How does distillation work?

Answer 12

Sea water is heated until it boils. The salt remains in the liquid, and the steam is pure water. The steam is cooled and condensed to make potable water.

Distillation requires a lot of energy to boil the water, and also to cool the steam down to condense it. The waste water is very salty and can be difficult to dispose of in a sustainable way which does not harm marine ecosystems.

Question 13

How does reverse osmosis work?

Answer 13

Water is put under high pressure and passed through a membrane which has tiny pores (holes) in it. The pores allow water molecules through, but prevent most ions and molecules from passing through. Reverse osmosis requires expensive membranes and also produces a large volume of waste water, so its efficiency is often quite low.

Question 14

How is waster water treated?

Answer 14

1. Screening and grit removal to remove large particles
2. Sedimentation allows tiny particles to settle out from still water, which produces sewage sludge and effluent (the liquid which remains on top)
3. The sewage sludge is digested anaerobically by specific bacteria
4. The effluent is treated with aerobic bacteria to reduce the volume of solid waste

Question 15

Give 3 examples of pollutants that might need to be removed from water

Answer 15

1. Human waste contains harmful bacteria and high levels of nitrogen
   compounds which can harm aquatic ecosystems
2. Industrial waste water may contain harmful chemicals such as toxic metal compounds
3. Agricultural waste water may contain fertilisers or pesticides which can disrupt sensitive ecosystems

Question 16

How does phytomining work?

Answer 16

1. Plants are grown on a low-grade ore
2. The plants absorb metal ions through their roots and concentrate these ions in their cells
3. The plants are harvested and burnt
4. The ash left behind contains metal compounds

Potentially not needed: acid is added to the ash to produce a solution containing dissolved metal compounds and then the metal can be obtained by displacement reactions with scrap metal

Question 17

How does bioleaching work?

Answer 17

Certain bacteria can break down low-grade ores to produce an acidic solution containing metal ions. The solution is called a leachate.
The metal ions are then extracted with displacement reactions or by using electrolysis.

Question 18

What are some advantages and disadvantages of phytomining?

Answer 18

D: It is a slow process - must wait for plants to grow

A: Can extract valuable metals from low grade ores when it is not usually economic to do so
Conserves limited supplies of high grade ores
A carbon neutral process with a low environmental impact

Question 19

What are some advantages and disadvantages of bioleaching?

Answer 19

A: It does not need high temperatures to happen

D: It produces toxic substances like sulphuric acid which damages the environment

Question 20

What are the 5 stages of an LCA?

Answer 20

RMUD

1. Extracting and processing raw materials
2. Manufacturing and packaging
3. Use and operation during its lifetime
4. Disposal at the end of it’s useful life
5. Transport and distribution at every stage

Question 21

What are LCAs used for?

Answer 21

Used to assess the environmental impact of the manufacture and use of different materials or products

GOOD NOTES IN BOOK AND ONLINE FOR LCAS

Question 22

What are some factors that are quantifiable in an LCA?

Answer 22

• Use of water
• Resources
• Energy sources
• Production of waste

Numerical values are hard to assign to effects of pollutants and requires value judgements so LCA is not a purely objective process

Question 23

What are some disadvantages of LCAs?

Answer 23

Sometimes require judgements about the effect on the environment and there could be bias if the LCA is completed by the company

Question 24

Why is recycling important?

Answer 24

Metals, glass, ceramics and most plastics require raw materials that are finite resources
Obtaining these resources often has environmental impacts (e.g. mining)

Question 25

What are some advantages of recycling?

Answer 25

- Fewer quarries and mines are needed to extract finite reserves of metal ores - Less crude oil needs to be extracted from the crust as a raw material for making plastics - Less energy is needed for recycling compared with making a new product from natural resources, so the emission of greenhouse gases is reduced - The amount of waste that is disposed of in landfill is reduced

Question 26

What are some disadvantages of recycling?

Answer 26

- The collection and transport of used items needs organisation, workers, vehicles and fuel - It can be difficult to sort different metals from one another - The sorted metal may need to be transported to where it can be turned into ingots The amount of sorting required depends on the purity of the mixture of metals/materials, and also on how pure you need the final recycled metal to be. For example, copper for electrical wiring requires a very high purity, so if wiring is made from recycled copper, the waste copper will need processing before being melted again into copper for wiring. However, steel used in construction doesn't need such a high purity. This means that scrap iron can easily be added to the steel furnace when steel is being made. This reduces the cost of making steel from iron ore.

Question 27

How does mining aluminium become a product?

Answer 27

1. Quarrying/mining of bauxite (Aluminium ore) 2. Formation of aluminium oxide 3. Electrolysis to form aluminium 4. Aluminium is melted 5. It is then cast to form a product - Product can be shredded to form aluminium (stage after electrolysis)

Question 28

How is glass made?

Answer 28

1. Obtain sand, soda ash, limestone and other chemicals 2. Melt them and blow the glass to form the product - To recycle the glass can be crushed and redo stage 2