Chemistry Topic 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 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, one or UV light
-chlorine is a toxic gas so the amount added to water has to beg be carefully monitored
-using UV 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

What are the processes involved in sewage treatment?

Answer 6

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

Question 7

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

Answer 7

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

Question 8

What is phytomining?

Answer 8

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 9

What is bioleaching?

Answer 9

Bioleaching uses bacteria to produce leachate solutions that contain metal compounds

Question 10

What is the main advantage and disadvantage of these methods?

Answer 10

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 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 of recycling?

Answer 13

-less acid rain
-conserved energy for extraction saved less mining
-quarrying less waste less landfill creates creates local employment

Question 14

What are the disadvantages of recycling?

Answer 14

-collection problems
-cost of transport
-difficult to separate metal from appliances

Question 15

What is corrosion and how is it prevented?

Answer 15

-Corrosion is the destruction of materials by chemical reactions with substances in the environment e.g. rusting

-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 16

Describe the sacrificial protection

Answer 16

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

Question 17

How are the properties of polymers determined?

Answer 17

Depend on what monomers they are made from and the conditions under which they are made

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

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 are surrounded by a binder/matrix material that holds these fibres/fragments together

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 the phosphate rock utilised in the production of fertilisers?

Answer 23

-phosphate rock is reacted with nitric acid to produce phosphoric acid and calcium nitrate
-phosphate rock can be reacted with sulphuric acid to produce a mixture of calcium phosphate and calcium sulfate