C10

Question 1

What do humans use Earth’s resources for?

Answer 1

Warmth; shelter; food and transport

Question 2

What do natural resources provide?

Answer 2

Food, timber, clothing and fuels

Question 3

What’s the difference between finite and renewable resources?

Answer 3

Finite means the resource will run out. The rate it is use is faster than it is being made. Renewable is the opposite.

Question 4

What is potable water?

Answer 4

Water that is safe to drink (not necessarily pure water as it contains dissolved substances)

Question 5

How is potable water produced in the UK? (3)

Answer 5

1. Choosing an appropriate source of freshwater e.g. lakes. 2. Filtration - filter the solids out through filter beds. 3. Sterilising to kill any harmful bacteria - using ozone; UV light or chlorine.

Question 6

How is potable water produced in other countries where freshwater is limited and why is it harder?

Answer 6

Desalination by distillation or reverse osmosis of salty water. It requires much more energy which is much more expensive.

Question 7

Required practical 8 - pure water.

Answer 7

1. Check pH of water using universal indicator to test for dissolved acids or alkalis. 2. To test for other dissolved things: Weigh an evaporating basin with scales. 3. Fill with water and place on tripod over Bunsen burner. 4. Gently heat until water has evaporated. 5. If the mass increases then there are dissolved solids because they now crystallise whilst the water has gone.

Question 8

What are some examples of sewage?

Answer 8

1. Home activities like baths and toilets. 2. Industrial processes like the Haber process. 3. Sewage from agriculture.

Question 9

How does sewage treatment work? (5)

Answer 9

1. The sewage is screened to remove any solid bit. 2. Sedimentation - heavier sludge goes to the bottom whilst the effluent floats on top. 3. Effluent is removed by aerobic digestion. 4. Sludge is broken down by anaerobic digestion. 5. Methane gas released from sludge can be used as an energy source while the rest can be a fertiliser.

Question 10

What are 2 ways to extract low grade copper ores?

Answer 10

Phytomining and bioleaching

Question 11

What does phytomining do?

Answer 11

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 12

What does bioleaching do?

Answer 12

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

Question 13

What is another way to get copper?

Answer 13

Displacement or electrolysis

Question 14

What is a life cycle assessment?

Answer 14

Looks at every stage of a products life to assess the impact it would have on the environment

Question 15

What are the 4 stages of a life cycle assessment?

Answer 15

1) Getting the raw materials 2) Manufacture and packaging 3) Using the product 4) Product disposal

Question 16

Compare the life cycle assessments for a plastic vs paper bag.

Answer 16

Plastic: made of crude oil (non renewable); fractional distillation and cracking and polymerisation and less waste; can be reused; recyclable but no biodegradable. Paper: made of timber; lots of waste made; only used once; biodegradable; non toxic and can be recycled.

Question 17

What is corrosion?

Answer 17

The destruction of materials by chemical reactions with substances in the environment.

Question 18

What is an example of corrosion?

Answer 18

rust

Question 19

What does iron need so it can rust?

Answer 19

Air and water

Question 20

How can corrosion be prevented?

Answer 20

By applying a coating that acts as a barrier such as greasing, painting electroplating (coating the material with a metal). OR Sacrificial protection.

Question 21

What is an example of corrosion be prevented?

Answer 21

Aluminium has an oxide coating that protects the metal from further corrosion.

Question 22

What is sacrificial protection?

Answer 22

Where a metal, for example iron, is coated in another more reactive metal, such as zinc, that will oxidise more readily protecting the iron from corrosion. The layer is simply replaced when it has corroded.

Question 23

What is the alloy bronze made up of?

Answer 23

Copper and tin.

Question 24

What is the alloy brass made up of?

Answer 24

Copper and zinc.

Question 25

What is 24 carat and 18 carat gold?

Answer 25

24 carat is fully gold and 18 carat is 75% gold.

Question 26

What is steel made up of?

Answer 26

Iron and others like carbon.

Question 27

What is high carbon and low carbon steel like?

Answer 27

High - strong but brittle. Low - softer and more easily shaped.

Question 28

What type of steel is hard and resistant to corrosion?

Answer 28

Stainless steel - contains chromium and nickel

Question 29

What type of density do aluminium alloys have?

Answer 29

Low

Question 30

What can we use to reduce waste and environmental impacts?

Answer 30

Reuse, reduce our use, recycle

Question 31

What are some things which are produced from limited raw materials?

Answer 31

Metals. Glass. Building materials. Clay ceramics and most plastic.

Question 32

What is something which can be recycled?

Answer 32

Glass bottles can be crushed and melted to make other glass products.

Question 33

How can metals be recycled and what is an example?

Answer 33

Recycled by melting and recasting or reforming into different products. Amount of separation required for recycling depends on the materials and their properties. E.g. some scrap steel can be added to iron to from a blast furnace to reduce amount of iron extracted from iron core.

Question 34

What is most glass made of?

Answer 34

Soda - lime glass; made by heating a mixture of sand; sodium carbonate and limestone.

Question 35

What is another type of glass?

Answer 35

Borosilicate glass; made from sand and boron trioxide. It melts at a higher temperature than soda - lime glass.

Question 36

What do thermosoftening polymers do when heated?

Answer 36

They melt.

Question 37

What do thermosetting polymers do when heated?

Answer 37

They do not melt.

Question 38

How is low and high density produced from ethene and what are some examples?

Answer 38

Low - made from ethene at a moderate temperature but a high pressure. Flexible so used for bottles and bags. High - lower temperature and lower pressure and a catalyst. More rigid so used for drainpipes.

Question 39

What's the difference between thermosoftening and thermosetting in terms of their structure?

Answer 39

Thermosoftening contains individual polymers entwined together with weak forces. Thermosetting contain monomers that for cross links between polymers and chains; holding them together in a solid structure.

Question 40

What is a composite?

Answer 40

Most composites are made of two materials, a matrix or binder surrounding and binding together fibres or fragments of the other material - called a reinforcement.

Question 41

What are some examples of composites?

Answer 41

Fibreglass; carbon fibre; concrete; wood

Question 42

What does the Haber process produce?

Answer 42

Ammonia which can be used to produce nitrogen based fertilisers.

Question 43

What are the raw materials for the Haber process?

Answer 43

Nitrogen from the air and Hydrogen from natural gas

Question 44

How does the Haber process work?

Answer 44

1. Nitrogen and hydrogen are passed over an iron catalyst at around 450*c and 200 atmospheres of pressure. 2. Some of the hydrogen and nitrogen react to form ammonia. 3. Because the reaction is reversible some of the ammonia breaks down into nitrogen and hydrogen. 4. On cooling the liquid ammonia can be removed from the mixture. 5. The unreacted nitrogen and hydrogen are recycled and reused again.

Question 45

What's the equation for the Haber process?

Answer 45

N2(g) + 3H2(g) = 2NH3(g)

Question 46

What are the conditions needed for the Haber process and what do they do in reality and why?

Answer 46

1. Low temperature but it means a slower rate of reaction so we actually compromise at 450 degrees. 2. High pressure but it is quite expensive and dangerous so we compromise at 200. 3. Iron catalyst speeds up the reaction but doesn't affect the yield.

Question 47

What do fertilisers actually do?

Answer 47

Provide the plant with the 3 elements if they are missing any. The crops grow faster and bigger.

Question 48

What do NPK fertilisers contain?

Answer 48

Nitrogen; phosphorus; potassium

Question 49

What can be mined as a source of potassium?

Answer 49

potassium chloride and potassium sulphate

Question 50

What are the different reactions of phosphate rock?

Answer 50

phosphate rock with nitrate acid --> phosphoric acid + calcium nitrate. phosphate rock with sulfuric acid --> phosphoric acid calcium sulfate. phosphate rock with phophoric acid --> calcium phosphate

Question 51

How is the reaction for NPK fertlisers different in industry vs the lab?

Answer 51

In industry: reaction is carried out in large tubs; exothermic reaction and is very concentrated. In the lab: reaction is a smaller scale with titrations and crystallistation. Low concentration; less heat; more safe.