C10

Question 1

What do humans use the earths resources for?

Answer 1

To provide warmth, shelter, food and transport.

Question 2

What do natural resources supplemented by agriculture provide?

Answer 2

Food,timber,clothing and fuels

Question 3

What are finite resources from the earth,oceans and atmosphere processed to provide?

Answer 3

Energy and materials

Question 4

Why does chemistry play an important role?

Answer 4

Chemistry plays an important role in improving agricultural and industrial processes to provide new products and in sustainable development, which is development that meets the needs of current generations without compromising the ability of future generations to meet their own needs.

Question 5

State examples of natural products that are supplemented or replaced by agricultural and synthetic products

Answer 5

An example of a natural product that has been supplemented/replaced by synthetic products is fertiliser. Farmers used to use (some still do) animal excrement to fertilise their fields, now we use the Haber Process to produce fertilisers from ammonia.

Question 6

What is the difference between finite and renewable resources?

Answer 6

Finite resources from the Earth’s crust , oceans and atmosphere will one day run out. They can be processed to provide energy and useful materials. E.g coal

Renewable resources are those which will not run out in the foreseeable future. E.g Tidal power, wind

Question 7

Note:

Answer 7

AQA says that students should be able to:

• state examples of natural products that are supplemented or replaced by agricultural and synthetic products
• distinguish between finite and renewable resources given appropriate information.

Question 8

Note:

Answer 8

AQA says that students should be able to:

• extract and interpret information about resources from charts, graphs and tables
• use orders of magnitude to evaluate the significance of data.

Question 9

Why is water of appropriate quality?

Answer 9

Water of appropriate quality is essential for life. For humans, drinking water should have sufficiently low levels of dissolved salts and microbes.

Question 10

What is water that is safe to drink called?

Answer 10

Water that is safe to drink is called potable water. Potable water is not pure water in the chemical sense because it contains dissolved substances.

Question 11

What do the methods used to produce potable water depend on?

Answer 11

The methods used to produce potable water depend on available supplies of water and local conditions.

Question 12

What happens in the UK with rain?

Answer 12

In the United Kingdom (UK), rain provides water with low levels of dissolved substances (fresh water) that collects in the ground and in lakes and rivers, and most potable water is produced by:
• choosing an appropriate source of fresh water
• passing the water through filter beds
• sterilising.

Question 13

What are sterilising agents used for and state examples

Answer 13

Sterilising agents used for potable water include chlorine, ozone or ultraviolet light.

Question 14

If supplies of fresh water are limited what happens?

Answer 14

If supplies of fresh water are limited, desalination of salty water or sea water may be required.

Question 15

How is desalation done?

Answer 15

Desalination can be done by distillation or by processes that use membranes such as reverse osmosis.These processes require large amounts of energy.

Desalination can be produced by distillation of sea water. In distillation, sea water is heated to over 100°C. The water vapour produced does not contain salt. It is cool and condenses to make pure water through desalination. This is an expensive process, as lots of energy is needed to boil large volumes of water.

Question 16

Distinguish between potable water and pure water

Answer 16

Potable water is the water which is filtered and treated properly and is finally free from all contaminants and harmful bacteria. This purified water is fit to drink, or it can be called ‘drinking water after the purification processes and is safe for both cooking and drinking.

Question 17

Describe the differences in treatment of ground water and salty water

Answer 17

Waste and ground water can be made potable by sedimentation, filtration and chlorination. Sea water can be made potable by using simple distillation. Water used in analysis must not contain any dissolved salts which would interfere with the sensitivity of the tests.

Question 18

Give reasons for the steps used to produce potable water

Answer 18

This water contains low levels of dissolved substances. Most potable water in the UK is produced from naturally occurring fresh water by: passing the water through filter beds to remove insoluble particles. sterilising the water to kill microbes.

Question 19

Practical 13

Answer 19

AAAA

Question 20

What do urban lifestyles and industrial processes produce?

Answer 20

Urban lifestyles and industrial processes produce large amounts of waste water that require treatment before being released into the environment.

Question 21

What do sewage and agricultural waste require?

Answer 21

Sewage and agricultural waste water require removal of organic matter and harmful microbes. Industrial waste water may require removal of organic matter and harmful chemicals.

Question 22

What does sewage treatment include?

Answer 22

• screening and grit removal
• sedimentation to produce sewage sludge and effluent
• anaerobic digestion of sewage sludge
• aerobic biological treatment of effluent.

Question 23

What is the relative ease of obtaining potable water from waste?

Answer 23

Waste and ground water can be made potable by sedimentation, filtration and chlorination

Question 24

What is the relative ease of obtaining potable water from the ground?

Answer 24

Ground water can be made potable by sedimentation, filtration and chlorination

Question 25

What is the relative ease of obtaining potable water from salt water?

Answer 25

Reverse osmosis can remove the salt. By using a process called reverse osmosis, we can remove the salt from sea water. A membrane is used to do this. High pressure is applied to the sea water, to push water molecules through the membrane; the salt is left behind.

Using sea water can be expensive. The process of using sea water to create potable water is very expensive. This is because reverse osmosis uses a lot of energy to produce high pressure.

Question 26

What is the problem with the Earth’s resources of metal?

Answer 26

They are limited

Question 27

What is the problem with copper ores

Answer 27

They are becoming scarce

Question 28

What are the new methods of extracting copper and what do they avoid?

Answer 28

New ways of extracting copper from low-grade ores include phytomining, and bioleaching.
These methods avoid traditional mining methods of digging, moving and disposing of large amounts of rock.

Question 29

What does phytomining use?

Answer 29

Phytomining uses plants to absorb metal compounds. The plants are harvested and then burned to produce ash that contains metal compounds.

Question 30

What is bioleaching?

Answer 30

Bioleaching uses bacteria to produce leachate solutions that contain metal compounds.

Question 31

What can metal compounds be compressed for? (State examples)

Answer 31

The metal compounds can be processed to obtain the metal. For example, copper can be obtained from solutions of copper compounds by displacement using scrap iron or by electrolysis.

Question 32

Evaluate alternative biological methods of metal extraction

Answer 32

• plants are grown on a low grade ore.
• the plants absorb metal ions through their roots and concentrate these ions in their cells.
• the plants are harvested and burnt.
• the ash left behind contains a higher concentration of the metal than the original ore.

Question 33

Note:

Answer 33

AQA says that students should be able to evaluate alternative biological methods of metal extraction, given appropriate information.

Question 34

What do LCAs stand for?

Answer 34

Life cycle assessment

Question 35

What are Life cycle assessments carried out to do?

Answer 35

Life cycle assessments (CAs) are carried out to assess the environmental impact of products in each of these stages:
• extracting and processing raw materials
• manufacturing and packaging
• use and operation during its lifetime
disposal at the end of its useful life, including transport and
distribution at each stage.

Question 36

What can be easily quanitified?

Answer 36

Use of water, resources, energy sources and production of some wastes can be fairly easily quantified.

Question 37

What is the problem with allocating numerical values to polutant effects?

Answer 37

Allocating numerical values to pollutant effects is less straightforward and requires value judgements, so LCA is not a purely objective process.

Question 38

What can selective or abbreviated LCAs can be devised to do?

Answer 38

Selective or abbreviated CAs can be devised to evaluate a product but these can be misused to reach pre-determined conclusions, eg in support of claims for advertising purposes.

Question 39

Carry out simple comparative LCAs for shopping bags made from plastic

Answer 39

Raw materials - carry out simple comparative CAs for shopping bags made from plastic

Manufacture - Cheaper to make large quantities of bags from plastic.

Use - Lower impact on the environment because plastic bags are usually stronger so they can be reused many times.

Disposal - Can sometimes be collected and recycled; if disposed of as litter, they do not biodegrade; in landfill, may take decades or centuries to degrade.

Question 40

Carry out simple comparative LCAs for shopping bags made from paper

Answer 40

Raw materials - Can be made from recycled paper, or from trees. Making paper from trees requires more energy than recycling paper, but much less than making plastics.

Manufacture - More expensive to make bags from paper because the handles must be glued on.

Use - Relatively short lifetime; can only be reused a limited number of times.

Disposal - Can be recycled easily; if disposed of in landfill, they biodegrade quickly.

Question 41

Note:

Answer 41

AQA says that students should be able to carry out simple comparative LCAs for shopping bags made from plastic and paper.

Question 42

What does the reduction in use, reuse and recycling of materials by end users reduce?

Answer 42

The reduction in use, reuse and recycling of materials by end users reduces the use of limited resources, use of energy sources, waste and environmental impacts.

Question 43

What things are made from limited raw materials?

Answer 43

Metals, glass, building materials, clay ceramics and most plastics are produced from limited raw materials.

Question 44

What much of whar comes from limited resources?

Answer 44

Much of the energy for the processes comes from limited resources.

Question 45

What does obtaining raw materials from the Earth cause?

Answer 45

Obtaining raw materials from the Earth by quarrying and mining causes environmental impacts.

Question 46

What can be reused? (State an example)

Answer 46

Some products, such as glass bottles, can be reused. Glass bottles can be crushed and melted to make different glass products. Other products cannot be reused and so are recycled for a different use.

Question 47

How can metals be recycled?

Answer 47

Metals can be recycled by melting and recasting or reforming into different products.

Question 48

What does the amount of separation required for recycling depends on? (State an example)

Answer 48

The amount of separation required for recycling depends on the material and the properties required of the final product.

For example, some scrap steel can be added to iron from a blast furnace to reduce the amount of iron that needs to be extracted from iron ore.

Question 49

Note:

Answer 49

AQA says that students should be able to evaluate ways of reducing the use of limited resources, given appropriate information.

Question 50

Evaluate ways of reducing the use of limited resources

Answer 50

Everyday materials such as glass, metal, plastics, ceramics are produced from natural but finite sources.
Some products made from these materials can be reused which saves energy and decreases the environmental impact.
Glass bottles only need to be washed and sterilised before they can be reused.