Unit 10 - Using Resources

Question 1

What is sustainable
development?

Answer 1

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

Question 2

In the UK, potable (safe to
drink) water is produced by…?

Answer 2

• choosing an appropriate source of fresh water
• passing the water through filter beds to remove any solids
• sterilising to kill microbes

Question 3

What are the sterilising agents
for potable water?

Answer 3

Sterilising agents used for potable water include chlorine, ozone or ultraviolet light.
* Chlorine is a toxic gas so the amount added to water has to be carefully monitored.
* Using ultraviolet light to kill microbes avoids adding chemicals to the water but is more expensive

Question 4

How is desalination carried
out?

Answer 4

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

Question 5

What is reverse osmosis?

Answer 5

Sea water is passed through a membrane that only allows through the water molecules. It needs high pressure to push the water through the membrane. The high pressure requires a lot of energy to produce.

Question 6

How is wastewater produced
and how is it treated?

Answer 6

• Urban lifestyles and industrial processes produce large amounts of waste water that require treatment before being released into the environment.
• 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 7

What are the processes
involved in sewage treatment?

Answer 7

Sewage treatment includes:
- screening and grit removal
- sedimentation to produce sewage sludge and effluent
- anaerobic digestion of sewage sludge
- aerobic biological treatment of effluent

Question 8

What do new methods of mining avoid in terms of disadvantages of traditional mining?

Answer 8

Avoids the disadvantages of traditional mining methods of digging, moving and
disposing of large amounts of rock

Question 9

What is phytomining?

Answer 9

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

Question 10

What is bioleaching?

Answer 10

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

Question 11

What are the main advantages
and disadvantages of
phytomining and bioleaching?

Answer 11

These methods need less energy than traditional methods, and can work on low
concentration ores but are slow to carry out.

Question 11

Describe the stages of LCAs

Answer 11

Life Cycle Assessments (LCAs) 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 12

How do we reduce the use of
resources?

Answer 12

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

Question 13

What are the advantages and
disadvantages of recycling?

Answer 13

Advantages of recycling: less acid rain (pollution) metal ore reserves last longer / conserved energy for extraction saved less mining / quarrying less waste less landfill creates local employment
Disadvantages of recycling ; collection problems transport problems/ cost of transport difficult to separate metal from appliances/sort

Question 14

What is corrosion and how is
it prevented?

Answer 14

Corrosion is the destruction of materials by chemical reactions with substances in the environment, e.g. rusting.
Corrosion can be prevented by applying a coating that acts as a barrier, such as greasing, painting or electroplating. These methods stop the air or water coming into contact with the metal.

Question 15

Describe the sacrificial
protection

Answer 15

Some coatings are reactive and may contain corrosion inhibitors or a more reactive metal.
If two metals are in contact the more reactive metal will corrode instead of the less reactive one, e.g. zinc is used to galvanise iron and when scratched, provides sacrificial protection because zinc is more reactive than iron.

Question 16

Describe the compounds and the uses of bronze, brass, gold and silver and copper and zinc, aluminium-magnesium and steels

Answer 16

Bronze - an alloy of copper and tin, used for making statues and decorative objects.
Brass - an alloy of copper and zinc used for producing water taps and door fittings.
Gold used as jewellery is usually an alloy with silver, copper and zinc (The proportion of gold in the alloy is
measured in carats, with pure gold being 24 carat, e.g. 18 carat gold is 75% gold.)
Aluminium-magnesium alloys are low density and used in aerospace manufacturing.
Steels - alloys of iron that contain specific amounts of carbon and other metals. High carbon steel is
strong but brittle. Low carbon steel is softer and more easily shaped. Steels containing chromium and
nickel (stainless steels) are hard and resistant to corrosion.

Question 17

How are the properties of
polymers determined?

Answer 17

The properties of polymers depend on what monomers they are made from and
the conditions under which they are made. For example, low density (LD) and high
density (HD) poly(ethene) are produced from ethene, using different catalysts and
reaction conditions.

Question 18

Describe the structures of
thermosoftening and
thermosetting polymers

Answer 18

Thermosetting polymers do not melt on heating. The polymer molecules are linked
to each other by strong cross-links. Thermosoftening polymers soften easily on
heating and can then be remoulded, keeping the new shape on cooling. The
polymer molecules are attracted to each other by weak intermolecular forces.

Question 19

How is glass made?

Answer 19

Most of the glass we use is soda-lime glass, made by heating a mixture of sand,
sodium carbonate and limestone. Borosilicate glass, made from sand and boron
trioxide, melts at higher temperatures than soda-lime glass

Question 20

How are clay ceramics made?

Answer 20

Clay ceramics, including pottery and bricks, are made by shaping wet clay and
then heating in a furnace.

Question 21

How are composites formed?

Answer 21

Fibres or fragments of one material (reinforcement) are surrounded by a
binder/matrix material that holds these fibres/fragments together.
E.g. fibreglass - glass fibres bound together in a polymer, used for making storage
tanks.

Question 22

How are compounds of
nitrogen, phosphorus and
potassium used?

Answer 22

Compounds of nitrogen, phosphorus and potassium are used as fertilisers to
improve agricultural productivity. NPK fertilisers contain compounds of all three
elements

Question 23

How is industrial production of
NPK fertilisers achieved?

Answer 23

Ammonia can be used to manufacture ammonium salts. The ammonium sulfate, phosphate, and nitrate can be produced by reaction of ammonia with the requisite acid.
2 NH3 + H2SO4 → (NH4)2SO4
2 NH3 + H3PO4 → (NH4)3PO4
NH3 + HNO3 → NH4NO3
*nitric acid is itself made from ammonia

Question 24

How is the phosphate rock utilised
in the production of fertilisers?

Answer 24

• Phosphate rock is reacted with nitric acid to produce phosphoric acid and
  calcium nitrate.
• Phosphate rock can be reacted with sulfuric acid to produce a mixture of calcium
  phosphate and calcium sulfate
• Phosphate rock can be reacted with phosphoric acid to produce calcium
  phosphate.