Using Resources

Question 1

What is a renewable energy source?

Answer 1

Sources of power that quickly replenish themselves and can be used again

Question 2

What is a finite energy source?

Answer 2

Sources have a limited supply that will eventually run out

Question 3

What is potable water?

Answer 3

Potable water is water that is safe for humans to drink. This means it contains a sufficiently low level of dissolved salts and microbes (so it is not pure)

Question 4

How is rain water treated to turn it into potable water?

Answer 4

1) Water is passed through a mesh screen to remove large bits (twigs, stones)
2) Chemicals are added to make solids and microbes stick together to form sediment and sink.
3) Anaerobic digestion of sewage sludge
4) The water is then sterilized with chlorine to kill any microbes left.

Question 5

How is salt water treated to turn it into potable water

Answer 5

If only sea water is available, desalination is required. This can be done through distillation or reverse osmosis however both are very expensive.

Question 6

What is phytomining?

Answer 6

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

Question 7

What is bioleaching?

Answer 7

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

Question 8

What are life cycle assessments?

Answer 8

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 9

What is corrosion?

Answer 9

Corrosion is the destruction of materials by chemical reactions with substances in the environment. Rusting is an example of corrosion (air and water).

Question 10

How can corrosion be prevented?

Answer 10

Corrosion can be prevented by applying a coating that acts as a barrier, such as greasing, painting or electroplating.

Question 11

Explain sacrificial protection in terms of relative reactivity.

Answer 11

Some coatings are reactive and contain a more reactive metal to provide sacrificial protection. This works by the more reactive metal donating electrons to the other metal so that it doesn’t corrode.
E.g. Zinc is used to galvanise iron.

Question 12

Why are alloys useful?

Answer 12

As most metals are too soft for everyday use and so are mixed with similar metals to make them harder.

Question 13

What is bronze an alloy of?

Answer 13

Bronze is an alloy of copper and tin and is used in electrical connectors

Question 14

What is brass an alloy of?

Answer 14

Brass is an alloy of copper and zinc and is used in tools

Question 15

What is gold (in jewellery) an alloy of?

Answer 15

Gold used as jewellery is usually an alloy with silver, copper and zinc.

Question 16

What is steel alloys of?

Answer 16

Steels are 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

Explain how low density and high density poly(ethene) are both produced and what are their characteristics?

Answer 17

LD and HD poly(ethene) are both made under different reaction conditions with different catalysts. LD has weaker forces of attraction meaning it has a lower melting point and is soft. HD has higher forces of attraction giving it a higher melting point.

Question 18

explain the difference between thermosoftening and

thermosetting polymers in terms of their structures.

Answer 18

Thermosoftening polymers are made of individual, tangled polymer chains that are easily separated and melted by heat. Thermosetting polymers consist of polymer chains that cross-link, so they do not melt when heated.

Question 19

Give two examples of composites

Answer 19

Bricks and pottery

Question 20

What is the Haber process?

Answer 20

The Haber process is used to make ammonia, which can be used to produce nitrogen-based fertilisers.

Nitrogen + Hydrogen Ammonia

Question 21

How are the nitrogen and hydrogen sourced in the Haber Process?

Answer 21

Nitrogen is obtained from the air hydrogen can be obtained from natural gas

Question 22

Describe the actual process itself?

Answer 22

The purified gases are passed over a catalyst of iron at a high temperature (about 450°C) and high pressure (about 200 atmospheres). Some of the hydrogen and nitrogen reacts to form ammonia. On cooling, the ammonia liquefies and is removed. The remaining
hydrogen and nitrogen are recycled.

Question 23

What are NPK fertilizers?

Answer 23

NPK fertilizers are fertilizers containing compounds of nitrogen, phosphorus, and potassium and is used to improve agricultural productivity.