Combined Chemistry - 5.10

Question 1

Suggest two ways in which Humans use the Earth’s resources.

Answer 1

Any two from:

warmth

shelter

food

transport

Question 2

What is meant by the term ‘sustainable development’?

Answer 2

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

Question 3

Give one example of a natural product that has been supplemented by, or replaced by, agricultural or synthetic products.

Answer 3

Suggestions include:

• Man made polymers have replaced natural rubber in a number of uses (e.g. car tyres)
• Concrete has replaced natural stone in some buildings
• Manure replaced by artificial fertilisers

Question 4

What is potable water?

Answer 4

Water that is safe to drink.

Question 5

Is potable water pure water?

Answer 5

No, because it contains dissolved substances

Question 6

What two things must drinking water have low levels of?

Answer 6

• Dissolved salts
• Microbes

Question 7

Describe how potable water is produced in the UK.

Answer 7

• Choose an appropriate source of fresh water
• Passing the water through the filter beds
• Sterilising the water

Question 8

Name the three different sterilising agents that can be used to make potable water.

Answer 8

• Chlorine
• Ozone
• Ultraviolet light

Question 9

Name two processes that can be used to desalinate water.

Answer 9

• Distillation
• Reverse Osmosis

Question 10

Name the process by which salt is removed from water.

Answer 10

Desalination

Question 11

Why does industrial waste water need treatment before being released into the environment?

Answer 11

To remove organic matter and harmful chemicals

Question 12

Why does sewage and agricultural waste water need treatment before being released into the environment?

Answer 12

To remove organic matter and harmful microbes

Question 13

Describe the four main stages in the process of sewage treatment

Answer 13

• Screening and grit removal
• Sedimentation to produce sewage sludge and effluent
• Anaerobic digestion of sewage sludge
• Aerobic biological treatment of effluent

Question 14

Higher Q. Why are new ways of extracting copper from low-grade ores needed?

Answer 14

High grade copper ores are running out.

Question 15

Higher Q. What big advantage do phytomining and bioleaching have over traditional copper mining methods?

Answer 15

These methods do not involve digging, moving and disposing of large amounts of rock.

Question 16

Higher Q. Describe the main stages in the phytomining process.

Answer 16

• Plants are grown on low-grade copper ores
• Plants absorb copper compounds
• Plants are harvested then burned
• Ash contains metal compounds

*Then electrolysis or displacement may be used to remove copper from the ash.

Question 17

Higher Q. How does bioleaching work?

Answer 17

Bacteria produce leachate solutions that contain metal compounds

*Then electrolysis or displacement may be used to remove copper from the ash.

Question 18

Higher Q. What two methods can be used to extract the copper from copper compounds after phytomining and bioleaching?

Answer 18

• Electrolysis
• Displacement using scrap iron

Question 19

What are the four stages of a product’s life that are assessed by Life Cycle Assessments (LCAs)?

Answer 19

• 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 20

What effects are difficult to predict by Life Cycle Assessments (LCAs), making them a little subjective?

Answer 20

Pollutant effects

Question 21

Name three materials that are produced from limited raw materials.

Answer 21

Any three from:

metals, glass, building materials, clay ceramics, plastics

Question 22

What are the four main advantages of reusing and recycling materials?

Answer 22

• Conserving limited resources
• Conserving energy
• Reducing waste (e.g. in landfill)
• Reducing environmental impacts

Question 23

How are glass bottles recycled?

Answer 23

They are crushed and melted to make different glass products.

Question 24

How are metals recycled?

Answer 24

They are melted and recasted or reformed into different products.

Question 25

Why is scrap steel added to iron from a blast furnace?

Answer 25

To reduce the amount of iron that needs to be extracted from iron ore.