Chapter 10

Question 1

In many cases resources such as houses food cars and fire are produced by

Example

Answer 1

Agriculture

For example cotton which is produced from a plant

Question 2

What does modern agriculture allow us to do

Answer 2

Grow enough cotton to meet the needs of the world
Humans also plant trees which can be used for timber or fuel

Agriculture helps us use the earths resources more efficiently

Question 3

And example of synthetic alternative of natural resources

Answer 3

Rubber
Natural rubber comes from the sap of a tree BUT
synthetic rubber is produced using crude oil and 2/3 in the world is synthetic

Question 4

What does finite mean

Answer 4

Cannot be replaced as quickly as they’re being used
For example
Fossil fuels- humans use millions of kilograms of fossil fuels everyday BUT
rate that fossil fuels are formed is much slower and one day = RUN OUT

Question 5

How are metals a finite resource

Answer 5

Huge amounts of metal are extracted from the earths crust and they will tin out if we continue using them at this rate

Question 6

What does renewable mean and example

Answer 6

Replace these resources as quickly as we use them so never run out
For example wood and fresh water

Question 7

What does sustainable mean

And why is it important for human activities to be

Answer 7

Wee can meet our needs without preventing future generations from meeting theirs

Question 8

Give an example of how chemistry plays an important role in how we use our resources

Answer 8

Artificial fertilisers allow us to grow more food with the land available and makes water safe to drink

Question 9

What 2 processes help us to extract metals more efficiently

Answer 9

Phytomining and bioleaching

Question 10

What risks is there with extraction finite resources

Answer 10

People have to balance social economic environmental effects of extracting finite resources for eg

Mining metal ores - is good because it’s useful products made and provides jobs and bring money to the area HOWEVVER
bad for the environment as it uses loads of energy , scars the landscape and produces loads of waste

Question 11

What materials do humans produce that we need for modern life

Answer 11

Glass metal plastic building materials clay ceramics
All produced from raw materials which are in limited supply

For eg metal = getting scarce
Raw materials often obtained by quarrying or mining = very harmful to the environment
FOR EG
Quarrying - produces large amounts of dust and destroys habitats and
Mining - release harmful chemicals into the environment and takes a lot of energy to turn raw materials into useful products
AND - energy usually often limited resources eg fossil fuels

VERY IMPORTANT WE TRY AND REDUCE OUR NEED FOR RAW MATERIALS - eg by reusing or recycling

Question 12

How can we reduce the amount of waste that we produce and have less harmful effect on the environment

Answer 12

Some products eg glass bottles can REUSED and also crushed and melted to make jars for example

Some products such as plastic bottles can be recycled for a different use eg make fleece jackets and carpets

Question 13

What do we do to recycle metals

Problems?

Answer 13

We melt them and recast them into different products

One of the problem- different metals usually need to be seperated before being recycled
HOWEVER depends on the properties of the final products

Question 14

What can be added to iron

Answer 14

Steel from a blastfunrnace

Reduced the amount of iron that we need to extract from iron

Question 15

What is bioleaching

What is phytomning

Answer 15

Bioleaching- bacteria used to Covert copper compounds in the ore into solouble copper compounds - separating out the copper from the ore in the process
Leachate- ( sol produced by the process) contains copper ions which can be extracted eg by electrolysis it displacement with a more reactive metal

Photo- growing plants in the soil that contains copper . The plants can’t use or get rid of the copper so it slowly builds up in the leaves . The plants can be harvested in a furnace
The ash contains copper compounds from which copper can be extracted by electrolysis

Copper are rich ore in short supply

Question 16

What is the life cycle assessment

Answer 16

Attempts to put a number on the environment impact of a product

Question 17

Main stages of life cycle assessment

Answer 17

Need to asses the environmental impact of extracting and processing the raw materials

Many modern products contains plastics and metals such as copper
Polymers such as plastics are produced using crude oil

1 - oil has to be extracted from the ground and then transported to oil refineries. The hydrocarbons have to be seperated then cracked
2 finally the polymer has to be produced

= large amount of energy
A lot of that energy will be generated by burning fossil fuels = climate change

Question 18

How does extracting metals take a huge amount of energy

Answer 18

First the ore has to be dug out of the nine and transported for processing
The metal then has to be extracted from ore and this can produce large amounts of toxic waste products
Once we have produced our raw materials we can then manufacture our product package it and transport it
= all stages require energy which may release harmful waste products

Question 19

Why do we need to assess the environmental impact of the product during its lifetime - life cycle assessment

Answer 19

For example toy- could involve large number of batteries

Producing batteries releases large amount of toxic waste

Question 20

Why do we need to assess the disposal of the products at the end of its useful life

Answer 20

Many modern products contain a number of harmful chemicals =
These chemicals have to be disposed carefully and may require a lot of energy
Also takes energy to transport used products eg to a landfill of recycling centre

Question 21

What are plastic bags produced by

Paper bags ….

Answer 21

Chemicals from crude oil whereas
Paper bags are made from wood from trees
Crude oil- non renewable BUT trees are renewable as we can simply plant more for them

Question 22

Extracting crude oil

Answer 22

Can be harmful to habitats eg if oil leaks
Felling trees for wood is also extremely destructive to habitats like forest

Both crude oil and wood need to be chemically processed = born a large amount of energy and releases waste products

Making paper - huge amounts of wate r

Question 23

Plastic shopping bags

Answer 23

Strong
Often re used for example bin liners HOWVER
Paper shop bags not as strong and tend to to tear
Often used once before being thrown

Question 24

At the end of plastic and paper bags lives…

Answer 24

Both have to be transported either for recycling or landfills
Paper bags are often heavier than plastic bags= so can take more energy to transport
HOWEVER plastic = non biodegradable = it is not broken down by micro organisms
HOWEVER
Paper bags break doe quickly especially when wet
Because plastic bags are non biodegradable they remain in the environment very long
= MAJOR FORM OF LITTER AND FILL UP LAND FILLS

Question 25

Life cycle assessment

Answer 25

We can measure use of water and energy and the production of some waste products

HOWEVER
we cannnot always be certain or how damaging these are to the environment
IN SOME CASES
got to make value judgements ( estimates) but may not always be accurate

Question 26

How can life cycle assess your be bisasrd

Answer 26

Support claims by advertisers

Question 27

What does safe water have to be like

Answer 27

Sufficiently low levels of dissolves salts such as sodium chloride and cannot have high levels of microbes such as bacteria

Question 28

What do scientists call water safe to drink BUT whys not the same as pure water

Answer 28

Portable water
But not the same as pure water
Pure water- Contains no dissolves substances at all
Potable water - contains dissolves substances although in quite small amounts

Question 29

What does rain water produce in the uk

Answer 29

Most of our potable water
Rain water contains low levels of dissolved substances
Rain water collects in the ground in aquifers ( rocks trap water underground) and in lakes and resvoir
= all good sources of fresh water

Question 30

How do we produce potable water

Answer 30

First chose a good source of fresh water

Pass the water through filter beds= remove materials such as leaves and suspended particles

Finally the water is sterilised to kill microbes . We use chlorine to sterilise potable water . HOWVER In parts of the world ozone and uktraviolrt used instead

Question 31

In poor countries no fresh water why can’t they drink their only available water sea water ??

Answer 31

Has very High levels of dissolved minerals in this case potable water produced from - DESALINATION = reduces the levels of dissolved minerals down to an acceptable level for potable water

Question 32

Ways to carry out desalination

Answer 32

Distillation

Pass the water through membranes = reverse osmosis
= both reduce levels of dissolved minerals
HOWVER
BOTH require very large amounts of energy and is expensive

Question 33

What does water that we use in agriculture and personal hygiene called

Answer 33

Waste water contains very large amount of organic molecules eg urine or faeces
And contains harmful micro organisms such as bacteria
Waste water must be carefully treated before being released back into the environment

Question 34

How is waste water treated

Answer 34

Sewage is screened by passing through a mesh = removes solids and pieces of grit

Sewage now settles in large sedimentation tanks = produces a liquid effluent and w semi solid sludge which sinks

Sludge = taken away and digested by anaerobic bacteria = produces biogas which can be burned for electricity

At the end the divested sludge can be used as fertilisers for farming

Question 35

What is the liquid effluent

Answer 35

Contains large amounts of organic molecules and harmful micro organisms - both of these need to be reduced before the water returns to the environment

Question 36

How are micro organisms and organic molecules reduced in liquid effluent

Answer 36

Air is bubbled through the liquid
This allows aerobic bacteria to multiply
In presence of oxygen the aerobic bacteria digest the organic molecules and harmful micro organisms
= safely discharged into nearby rivers

Question 37

A lot of water is used by the industry eg in making paper and chemicals how is water treated ??

Answer 37

Water is treated any harmful chemicals need to be removed

After this the water can safely enter the general sewage treatment

In some parts of the world treated sewage is used directly to produce potable water

Question 38

What is the easiest way to produce potable water

Answer 38

Use ground water from aquifers - safe to drink once been treated with chlorine
Aquifers sometimes be polluted eg with fertilisers from farms
SO
water from aquifers needs to be treated carefully

Question 39

We’re can we directly make potable water from

Answer 39

Waste water such as sewage
BUT
Many purification steps
SO only done in places were water is scarce

Salt water = desalinated to produce potable water = lot of energy and expensive