The Earth's resources - C14

Question 1

What is a finite resource

Answer 1

They are resources which are being used up quicker than they can be replaced

Question 2

Examples of finite resources

Answer 2

Coal, crude oil and natural gas

Question 3

What is an infinite resource

Answer 3

They are resources which are being replaced at the same rate as they are being used

Question 4

Examples of infinite resources

Answer 4

crops used to make biofuels

Question 5

what are the uses for water

Answer 5

solvent and a coolant

Question 6

What is potable water

Answer 6

Water that is fit to drink

Question 7

How is water made fit to drink

Answer 7

It is made fit by passing it through filter beds to remove solids and adding chlorine, ozone or by passing ultra-violet light through it to remove microbes

Question 8

how can water be purified

Answer 8

Distillation or desalination

Question 9

What is desalination

Answer 9

It is reverse osmosis which uses membranes to separate dissolved salts from salty water

Question 10

What is the disadvantage of desalination

Answer 10

Lots of energy is required to achieve a high pressure

Question 11

What is the disadvantage of distillation

Answer 11

It requires lots of energy

Question 12

What happens to waste water

Answer 12

It is treated at a sewage works before being released into the environment

Question 13

What are the steps to treating waste water

Answer 13

1. Screening
2. Primary treatment
3. Secondary treatment
4. Final treatment

Question 14

What is the screening step

Answer 14

It is the removal of large solids and grit

Question 15

What is the primary treatment step

Answer 15

The solids in the water are collected as sludge and the liquid goes to the next tank

Question 16

What is the secondary treatment step

Answer 16

Useful bacteria feed on organic matter and harmful microorganisms in aerobic conditions

Question 17

What is the final treatment step

Answer 17

The useful bacteria form a sediment at the bottom of the tank and either sent back into the secondary treatment tank or into where the sludge is kept

The water is now safe to discharge back into the environment but if the environment is sensitive the water can be run through a bed of sand

Question 18

What happens to the sludge

Answer 18

It is separated and broken down by anaerobic digestion and dried
It can be used as a fertiliser or a renewable source

Question 19

How is copper extracted

Answer 19

Smelting or adding it to sulfuric acid and then using it as an electrolyte or being displaced by scrap iron whilst in solution

Question 20

What is smelting

Answer 20

When the metal is made impure using air and high temperatures and is then used as the positive electrode is electrolysis

Question 21

What methods are used on low grade copper ores

Answer 21

bioleaching or phytomining

Question 22

What is phytomining

Answer 22

It is when plants absorb the metal ore and then are burnt and the metal is extracted from compounds in the ash

Question 23

What is bioleaching

Answer 23

It is when bacteria feed on the ores and produce a solution of metal ions which can be displaced by something and then used in electrolysis to make the pure metal

Question 24

What are LCA’s

Answer 24

They are assessments carried out to assess the environmental impacts of products or services

Question 25

How are LCA’s done

Answer 25

They assess each stage of the life cycle of the product 
These are:
Raw material extraction
Manufacture
Use/Reuse/Maintenance 
Recycle/Waste Management

Question 26

What are the disadvantages of LCA’s

Answer 26

They involve subjective judgements so not everyone will give the same answer

Question 27

what are the advantages of recycling metals

Answer 27

Saves energy and the finite resources and the pollution caused by the extraction of the metals is reduced