Topic 10 Using Resources

Question 1

1) Give one property of glass that makes it suitable for windows.

Answer 1

1) E.g. it is (generally) transparent

Question 2

2) What are the three substances used to make soda-lime glass?

Answer 2

2) Limestone, sand and sodium carbonate (soda)

Question 3

3) What are the two substances used to make borosilicate glass?

Answer 3

3) Sand and boron trioxide

Question 4

4) Give one use of clay ceramics.

Answer 4

E.g. pottery / bricks

Question 5

5) Describe two properties of ceramics.

Answer 5

5) There are a few properties you could pick here, e.g. high melting points, hard, brittle.

Question 6

6) Suggest why most lab glassware is made from borosilicate glass, rather than soda-lime glass.

Answer 6

6) Borosilicate glass has a higher melting point than soda-lime glass, so is more suitable for use in experiments that reach high temperatures because there’s less chance the glassware will melt.

Question 7

7) Thomas has some clay. He decides to make a 10-foot statue of Dmitri Mendeleev for his garden. How would the properties of clay allow him to do this?

Answer 7

7) Clay is soft, so it can be moulded into the shape of Mendeleev. Clay hardens when fired at high temperatures so, when Thomas is happy with the shape, he can fire it to form a hard, clay ceramic that will maintain its shape.

Question 8

1) Which of the following is a composite?
A. Wood
B. Aluminium
C. Steel
D. Peanut butter

Answer 8

1) Wood

Question 9

2) Give another example of a composite. What is it made from?

Answer 9

2) E.g. fibreglass (made from glass and plastic/a polymer) / carbon fibre (made from chains of carbon atoms, or carbon nanotubes, and a polymer) /concrete (made from a sand and gravel aggregate and cement).

Question 10

3) Explain what is meant by the term ‘matrix’ in a composite.

Answer 10

3) The material that surrounds the fibres or fragments of the other material in the composite, acting as a binder.

Question 11

4) Explain what is meant by the term ‘reinforcement’ in a composite.

Answer 11

4) The fibres or fragments of a material that are embedded in the matrix/binder.

Question 12

5) Suggest a composite that could be used to build a pavement. Explain why it is suited to this purpose.

Answer 12

5) E.g. concrete, because it is very strong.

Question 13

6) Composite E is made by embedding carbon nanotubes in a polymer. The polymer is strong, heat-resistant, lightweight and brittle. The carbon nanotubes are very strong and stiff, and have a low density. Suggest why these two materials might be combined together in this way, and suggest a use for composite E.

Answer 13

6) E.g. the polymer is brittle, so embedding the strong carbon nanotubes in it will make it more durable. The carbon nanotubes have a low density, so they can be added to the polymer without increasing its weight too much. A composite like this could be used in e.g. sports car/aerospace manufacturing.

Question 14

1) What are the conditions needed to make low density poly(ethene) from ethene?

Answer 14

1) Moderate temperature and high pressure.

Question 15

2) What happens when a thermosoftening polymer is heated?

Answer 15

2) It melts.

Question 16

3) What is high density poly(ethene) used for?

Answer 16

3) E.g. making water tanks/drainpipes.

Question 17

4) Explain why low density poly(ethene) is a more suitable material for plastic bags than high density poly(ethene).

Answer 17

4) It is flexible, whereas high density poly(ethene) is more rigid.

Question 18

5) Jasveer says “the properties of a polymer are only influenced by the conditions it was made under”.
Do you agree with her statement? Explain your answer.

Answer 18

5) Disagree. Although the conditions a polymer is made under do influence the polymer’s properties also depend on the monomers it is made from.
its properties.

Question 19

6) Describe the structure and bonding in a thermosoftening polymer.

Answer 19

6) Polymer chains (containing covalently-bonded atoms) entwined together with weak intermolecular forces between the chains.

Question 20

7) Why are thermosetting polymers rigid?

Answer 20

7) Thermosetting polymers contain monomers that can form cross-links between the polymer chains, holding the chains together in a solid, rigid structure.

Question 21

Which of the following can conduct heat?

a. glass
b. ploymers
c. metals
d. clay ceramics

Answer 21

1) Metals

Question 22

3) Explain why composites are versatile materials.

Answer 22

3) The properties of composites depend on the materials used for their matrix and reinforcement. So they can have a wide range of properties, depending on the materials that make them up.

Question 23

4) What are the advantages of using ceramic clay to make a garden plant pot, rather than low density poly(ethene)?

Answer 23

4) E.g. ceramic clay is stiffer and heavier than low density poly(ethene) (which is flexible and lightweight). Therefore ceramic clay would make a sturdier plant pot that would maintain
its shape.

Question 24

5) Give two reasons why metals are good materials for use in
electrical wiring.

Answer 24

5) E.g. metals can conduct electricity. They are also ductile, so can be drawn out into wires without breaking.

Question 25

6) Fibreglass is a composite made from fibres of glass embedded in a matrix made of polymer. Explain why fibreglass is used to make skis and surfboards.

Answer 25

6) Fibreglass is flexible and has low density, because of the plastic matrix. It is also very strong, because of the glass reinforcement.

Question 26

1) Bronze is an alloy of which two metals?

Answer 26

Copper and tin

Question 27

2) What name is given to the alloy formed from copper and zinc?

Answer 27

2) Brass

Question 28

Give a use for stainless steel. Why is it used for this?

Answer 28

E.g. cutlery, because it is hard and corrosion-resistant.

Question 29

4) Gold alloys are used to make jewellery. What unit of measurement is used to describe the proportion of gold in an alloy? What is the highest value on this scale?

Answer 29

4) Carat. 24 carat gold is the largest proportion of gold you can have (it is 100% gold).

Question 30

5) Suggest why alloys of aluminium are used in the aircraft industry, rather than pure aluminium.

Answer 30

5) E.g. aluminium metal has a low density, but is too soft for making aeroplanes. Aluminium alloys also have a low density, but are a lot stronger than pure aluminium.

Question 31

6) Explain how the level of carbon in steel affects its properties. Suggest one use for low carbon steel, and one use for high carbon steel.

Answer 31

6) Low carbon steels are softer and more easily shaped.

Higher amounts of carbon in the steel makes it stronger, but more brittle.

One example of a use of low carbon steel is in car bodies.

One example of a use of high carbon steel is in bridges.

Question 32

1) What is corrosion?

Answer 32

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

Question 33

2) True or false? Corrosion only occurs on the surface of a metal.

Answer 33

2) True. The surface of a metal is the only bit which is exposed to the environment, so it is the only bit that can corrode.

Question 34

3) Tinashe has an iron weather vane on his house. Suggest two things that could be done to prevent the weather vane rusting.

Answer 34

3) Take your pick from: e.g. paint or coat it in plastic / electroplate it / place it with a more reactive metal for sacrificial protection / galvanise it with zinc.

Question 35

4) Mystic Melanie accidentally teleports her iron key into an airless container of water. Will the key rust? Explain your answer.

Answer 35

4) The key will not rust. Both water and oxygen must be present in order for iron to rust.

Question 36

5) Explain what is meant by “sacrificial protection”.

Answer 36

5) Sacrificial protection involves coating/placing the material with a more reactive metal, so that water and oxygen will react with that instead of the material being protected.

Question 37

6) Forgetful Frank leaves a rod of iron and a rod of aluminium in an open pool of water for a long time. When he returns, he notices that the mass of the iron rod has decreased, but the mass of the aluminium rod has increased. Explain these observations.

Answer 37

6) When iron rusts, it produces a soft, crumbly solid that soon flakes away. This leaves more iron available to rust again, so the process continues and the iron is slowly destroyed, reducing its mass. When aluminium corrodes, it forms a layer of aluminium oxide on the surface that doesn’t flake away. Because oxygen is gained, the mass increases.

Question 38

1) What is meant by the term “finite resources”? Give an example of one.

Answer 38

1) E.g. finite (non-renewable) resources are resources that can’t be formed quickly enough to be considered replaceable. For example, fossil fuels, nuclear fuels, minerals and metal ores.

Question 39

2) What is meant by the term “natural resource”?

Answer 39

2) E.g. a natural resource is a resource that forms without human input, such as cotton or oil.

Question 40

3) Give an example of a natural resource that has been replaced by a man-made product or process. What has replaced it?

Answer 40

3)
E.g. rubber. It has been replaced by man-made polymers.

Question 40

3) Give an example of a natural resource that has been replaced by a man-made product or process. What has replaced it?

Answer 40

3)
E.g. rubber. It has been replaced by man-made polymers.

Question 41

3) Give an example of a natural resource that has been replaced by a man-made product or process. What has replaced it?

Answer 41

3)
E.g. rubber. It has been replaced by man-made polymers.

Question 42

4) Describe one advantage and one disadvantage of extracting finite resources.

Answer 42

4) Advantages: e.g. can make a wide range of useful products from them / provides jobs and brings money to areas where it is being extracted. Disadvantages: e.g. destroys habitats / uses lots of energy / generates waste / uses up materials that might be needed later.

Question 43

5) Matthew says “all natural resources are finite resources”. Cathy says “all natural resources must be renewable, because they come from the Earth”.
Which, if either, of them is correct?

Answer 43

5) Neither Matthew nor Cathy are correct. There are some renewable natural resources, such as timber (wood), and there are some finite natural resources, such as fossil fuels.

Question 44

6) A company is choosing a resource from which to make a new product. Resource A takes 10² years to form. Resource B takes 10* years to form.
From this information, which resource is the more sustainable choice?
What is the difference, in years, between the times it takes the resources to form?

Answer 44

6) Resource A is more sustainable, because it will be replaced in the least amount of time.

The difference is 10⁴ - 10²= 10,000 - 100 = 900 years

Question 45

1) How are metals usually recycled?

Answer 45

1) Melting them and then recasting them into the shape of the new product.

Question 46

2) What is “sustainable development”?

Answer 46

2) Sustainable development is an approach to development that meets the needs of present society while not damaging the lives of future generations.

Question 47

3) How can scrap steel help to reduce the amount of iron that needs to be extracted from iron ore?

Answer 47

3) Scrap steel contains iron, so it can be added to a blast furnace in place of iron ore during the extraction of iron, to reduce the amount of iron ore required.

Question 48

4) Sophie buys a lot of glass bottles. Suggest two things Sophie could do to reduce the amount of glass waste she produces.

Answer 48

4) E.g. she could reuse the glass bottles, so that she doesn’t have to buy as many. She could also recycle the glass, so that it doesn’t go to landfill sites.

Question 49

5) Suggest one way in which chemists can help to reduce damage to the environment caused by the demand for finite resources.

Answer 49

5) E.g. by developing catalysts so less energy/fuel is needed for industrial processes.

Question 50

6) Explain why recycling metals is better for the environment than extracting them from ores.

Answer 50

6) E.g. extracting metals from ores requires more energy than recycling them. This energy often comes from fossil fuels, which release greenhouse gases and pollutants. This can lead to negative effects like climate change and acid rain. Extracting metals also produces more

Question 51

1) True or false? Bioleaching and phytomining are better for the environment than traditional mining methods because they produce copper that does not need to be processed.

Answer 51

1) False. Bioleaching and phytomining do have a smaller impact on the environment than mining, however they still produce copper that needs to be processed.

Question 52

2) In bioleaching, what is meant by the term “leachate”?

Answer 52

2) The copper-containing solution that is produced from the ore.

Question 53

3) Describe how bioleaching works.

Answer 53

3) Bioleaching uses bacteria to convert metal ores into soluble compounds, separating the metal from the ore. The solution produced (the leachate) contains metal ions, which can be extracted by displacement or electrolysis.

Question 54

4) Describe how phytomining works.

Answer 54

4) Phytomining involves growing plants in soil that contains metal compounds. The plants absorb the metal compounds, so the metal gradually builds up in the leaves of the plant. The plants can then be harvested, dried and burned in a furnace. The ash contains soluble metal compounds from which the metal can be extracted by displacement or electrolysis.

Question 55

5) Suggest two reasons why scientists might want to investigate new methods to extract copper metal.

Answer 55

5) Here are a few possible answers: copper is valuable / copper ores are becoming scarce, so methods for extracting copper from low-grade ores are required to meet demand /
copper mining is damaging to the environment / copper mining uses a lot of energy.

Question 56

6) Suggest one disadvantage of phytomining, compared to bioleaching.

Answer 56

6) E.g. carbon dioxide will be released when the plants are burnt, which could
contribute towards climate change and global warming.

Question 57

1) What is a life cycle assessment (LCA)?

Answer 57

1) A study carried out to estimate the environmental impact of a product across its whole life cycle.

Question 58

2) What are the four stages of a product’s life that a LCA considers?

Answer 58

2) Extracting and processing raw materials, manufacturing and packaging, use and operation, disposal.

Question 59

3) The table on the right shows part of an LCA for plastic and paper shopping bags.
Explain how this information could be used to support a conclusion that paper bags are better for the environment than plastic bags.

Answer 59

3) Paper bags are made from timber, which is a renewable resource, whereas plastic bags are made from non-renewable crude oil. Therefore making paper bags saves limited finite resources. Paper bags are also biodegradable, unlike plastic bags, so won’t take up space in landfill or pollute land when they’re disposed of.

Question 60

4) What difficulties are associated with carrying out an LCA?

Answer 60

4) Many aspects of an LCA are difficult to quantify, for example, the exact amount of pollutants released, or the unsightliness of waste. Also, LCAs are not objective — they take into account the values of the person carrying them out, so they can be biased.

Question 61

5) How can companies misuse LCAs to their advantage?

Answer 61

5) Companies can use selective LCAS, which only show some of the impacts of a product on the environment. These can be deliberately written to support the claims of the company,
in order to give them positive advertising.

Question 62

1) Define potable water.

Answer 62

1) Water that is safe to drink.

Question 63

2. Name three sterilising agents for water.

Answer 63

2) E.g. chlorine gas, ozone, ultraviolet light

Question 64

3) True or false? Rain is a type of fresh water.

Answer 64

3) True

Question 65

4) Describe the general process for the treatment of fresh water. Explain why each step is necessary.

Answer 65

4) Fresh water is filtered, to remove any solid bits. The water is then sterilised to kill any harmful microbes or bacteria.

Question 66

5) Why is it preferable to produce potable water from fresh water, rather than from sea water?

Answer 66

5) The desalination of salt water is a very energy-intensive process, which makes it expensive and not practical for producing large quantities of potable water.

Question 67

6) Describe how distillation can be used to desalinate sea water.
What is an alternative method that could be used?

Answer 67

6) Sea water is heated in a flask beneath a condenser. The water boils, forming steam and leaving behind any dissolved salts in the flask. The steam passes through the condenser and turns back into liquid water, which is collected. An alternative method is reverse osmosis.

Question 68

1) Describe two sources of waste water.

Answer 68

1) E.g. household waste / agriculture / industrial processes

Question 69

2) What are the four stages of waste water treatment?

Answer 69

2) Screening, sedimentation, aerobic digestion and anaerobic digestion.

Question 70

3) What is removed from the water during the first step of sewage treatment?

Answer 70

3) Large bits of material, like twigs and plastic bags, and grit.

Question 71

4) What is the difference between effluent and sludge? How are each of them broken down?

Answer 71

4) Sludge is made up of heavier substances than effluent, so sinks to the bottom of the tank during sedimentation. Effluent is water with lighter particles suspended in it, so it floats on the top. Sludge is broken down by bacteria during anaerobic digestion. Effluent is broken down by bacteria during aerobic digestion.

Question 72

5) Why might additional stages of treatment be required for some samples of water?

Answer 72

5) If the water contains toxic substances, then additional treatment might be required.

Question 73

6) Why is it easier to obtain potable water from fresh water than from waste water?

Answer 73

6) Fewer processes are required with fresh water.

Question 74

7) Give one argument for obtaining potable water from the treatment of waste water, rather than the desalination of salt water. Why might people be against this idea?

Answer 74

7) E.g. the treatment of waste water uses less energy than the desalination of salt water.
However people might not like the idea of drinking water that used to be sewage. How lovely a whole card on waste.

Question 75

1) What is the balanced symbol equation for the reaction in the Haber process?

Answer 75

1) N₂ _(g) + 3H₂ _(g) + 2NH₃(₂) (+ heat)

Question 76

2) The Haber process is a reversible reaction.
Why does this make it difficult to obtain a high yield of product?

Answer 76

2) The reaction can go in both directions, so some of the ammonia produced breaks down into nitrogen and hydrogen again.

Question 77

3) Where does the hydrogen used in the Haber process come from?

Answer 77

3) E.g. reacting methane (from natural gas) with steam to form hydrogen and carbon dioxide 4) A catalyst would have no effect on the yield. Catalysts increase the rate of reaction, not the yield (because they increase the rate of the forward and backward reactions equally).

Question 78

4) A company that uses the Haber process wants to improve their product yield.
One scientist suggests using an iron catalyst. Explain the effect would if any,
on the percentage yield of the Haber process.

Answer 78

5) Increasing pressure would increase the rate of the Haber process. This is because there would be more reactant molecules per unit volume, so collisions would be more frequent.

Question 79

5) Explain the effect of increasing pressure on the rate of the Haber process.

Answer 79

5) Increasing pressure would increase the rate of the Haber process. This is because there would be more reactant molecules per unit volume, so collisions would be more frequent.

Question 80

6) The forward reaction in the Haber process is exothermic. The process is carried out at a temperature of 450 °C. Explain why the choice of temperature for the Haber process is often called a compromise.

Answer 80

6) The forward reaction of the Haber process is exothermic. Therefore low temperatures
are required to shift the equilibrium to favour the forward reaction and give a high yield of ammonia. However, if the temperature is too low then the rate of reaction is very slow, so a compromise temperature of 450 °C is used to achieve a decent yield at a good rate.

Question 81

1) NPK fertilisers contain compounds of which three elements?

Answer 81

1)
Nitrogen, phosphorous and potassium

Question 82

2) What are the reactants in the production of ammonium nitrate?

Answer 82

2) Ammonia and nitric acid

Question 83

3) How is potassium chloride obtained?

Answer 83

3) It is mined.

Question 84

4) What products are formed when phosphate rock reacts with nitric acid?

Answer 84

4) Phosphoric acid and calcium nitrate

Question 85

5) Why is ammonium nitrate a particularly good fertiliser?

Answer 85

5) It contains nitrogen from two sources (its formula is NH₄NO₃).

Question 86

6) In industry, ammonium nitrate is produced on a large scale using high concentrations of reactants that give a highly exothermic reaction. In the lab, a smaller scale is used with lower concentrations of reactants. Suggest an explanation for these differences.

Answer 86

6) E.g. using a lower concentration of reactants in the lab means a less exothermic reaction occurs, which makes the process safer for an individual to carry out. / Industry needs a larger scale to meet demand/maximise profits.

Question 87

7) Explain how fertilisers increase the productivity of farming.

Answer 87

7) Fertilisers increase and replenish the nutrients in the soil that plants need to grow. This means crops can be grown on the same land every year, and can grow faster and bigger.

Question 88

8) Suggest an advantage of using formulated fertilisers instead of manure.

Answer 88

8) E.g. formulated fertilisers are more widely available / easier to use have just enough of each nutrient.