Using Resources

Question 1

5 things humans use natural resources for

Answer 1

• energy and fuels for warmth
• building materials for shelter
• food through farming
• fuels for transport
• materials for clothing

Question 2

define finite resource

Answer 2

Resource that can only be used once and is in limited supply.

Question 3

define renewable resource

Answer 3

Resources which will not run out in the foreseeable future. This could be because the reserves of the resources is huge, or because the current rate of extraction is low.

Question 4

describe the role chemistry plays in sustainable development

Answer 4

Chemists try to improve agriculture and industrial processes to provide new products that allow humans to meet their needs in a sustainable way.

Question 5

what is sustainable development

Answer 5

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

Question 6

state an example of natural products that are supplemented/ replaces by agricultural and synthetic products

Answer 6

until 1910 all fertilisers were obtained from natural resources such as manure. However, the Haber process enabled humans to produce fertilisers from nitrogen in the air, and has allowed synthetic fertilisers to be produced.

Question 7

define potable water

Answer 7

Water that is safe to drink but is not pure water because it almost always contains dissolved impurities.

Question 8

discuss importance of water quality on human life

Answer 8

Water is essential for life. The water they need has to be of good enough quality (potable), which for humans means it needs low levels of dissolved salts and microbes.

Question 9

2 methods of desalinating salty water

Answer 9

distillation and reverse osmosis

Question 10

how is distillation used to deslinate salty water?

Answer 10

1. heat salt water
2. when water reaches boiling point, it evaporates leaving the salt in the flask
3. it will rise up and go down the condenser
4. the condenser will lower the temperature so the pure water will condense

Question 11

how is reverse osmosis used to desalinate salty water?

Answer 11

• Water is put under high pressure and passed through one side of a selectively permeable membrane to the other which has tiny pores in it.
• The pores allow water molecules through, but prevent most ions and molecules from passing through.
• The water is forced through from the more concentrated to more dilute side, leaving the salt

Question 12

what is waste water a product of?

Answer 12

urban lifestyles and industrial processes that includes organic matter, harmful microbes and harmful chemicals.

Question 13

describe the process of sewage treatment

Answer 13

1. screening and grit removal to remove large particles
2. sedimentation allows tiny particles to settle out from still water, which produces sewage sludge and effluent (the liquid which remains on top)
3. the sewage sludge is digested anaerobically by specific bacteria
4. the effluent is treated with aerobic bacteria to reduce the volume of solid waste

Question 14

is it easier to obtain potable water from waste water or from ground/salt water?

Answer 14

waste water

Question 15

2 alternative biological methods for extracting metals

Answer 15

phytomining and bioleaching

Question 16

describe the process of phytomining

Answer 16

Plants absorb mineral ions through their roots. Phytomining (also known as phytoextraction) makes use of this:
1. plants are grown on a low-grade
ore
2. the plants absorb metal ions through their roots and concentrate these ions in their cells
3. the plants are harvested and burnt
4. the ash left behind contains metal
compounds

Question 17

define bioleaching

Answer 17

Using bacteria to extract metals such as copper from their ores.

Question 18

describe the process of bioleaching

Answer 18

1. bacteria feed on the rock, turning insoluble copper compounds to soluble copper sulphate
2. soluble copper sulphate is washed out and collected in a tank
3. scrap iron is added so a displacement reaction can take place
4. eventually, enough copper builds up in the tank to filter the contents and remove the metal

Question 19

3 pos and 1 neg of phytomining

Answer 19

+ reduces the need to obtain new ore by mining
+ conserves limited supplies of high-grade ores
+ reduces the amount of rock waste that must be disposed of after traditional mining
- slow process

Question 20

pos and neg of bioleaching

Answer 20

+ does not need high temperatures
- produces toxic substances, including sulfuric acid, which damage the environment

Question 21

what are the 4 life cycle analysis (LCA) stages and what 2 things does each consider?

Answer 21

1. extracting and processing raw materials
   - what and where they come from
   - how much energy’s needed to process them
2. manufacturing and packaging
   - is the packaging sustainable?
   - does it take lots of energy to make?
3. use and operation during its lifetime
   - is it single use?
   - how rubust it is
4. disposal at the end of its useful life (including transport and distribution at each stage)
   - will it go to landfill?
   - can it be recycled?

Question 22

pos and neg of life cycle analysis

Answer 22

+ easy to work out accurate numerical values for parts of a LCA/ systematic
- but some parts of a LCA require judgements- not a totally objective process

Question 23

life cycle analysis of a shopping bag made from plastic

Answer 23

1. Raw materials- Crude oil is a finite resource; fractional distillation, cracking and polymerisation all require a lot of energy.
2. Manufacture- Cheaper to make large quantities of bags from plastic.
3. Use- Lower impact on the environment because plastic bags are usually stronger so they can be reused many times.
4. Disposal Can sometimes be collected and recycled; if disposed of as litter, they do not biodegrade; in landfill, may take decades or centuries to degrade.

Question 24

life cycle analysis of a shopping bag made from paper

Answer 24

1. raw materials- Can be made from recycled paper, or from trees. Making paper from trees requires more energy than recycling paper, but much less than making plastics.
2. manufacture- More expensive to make bags from paper because the handles must be glued on.
3. use- Relatively short lifetime; can only be reused a limited number of times.
4. disposal- Can be recycled easily; if disposed of in landfill, they biodegrade quickly.

Question 25

how can the consumption of raw resources be reduced?

Answer 25

The reduction in use, reuse and recycling of materials by end users

Question 26

how does reusing/ recycling reduce energy use?

Answer 26

* fewer quarries and mines are needed to extract finite reserves of metal ores * less crude oil needs to be extracted from the crust as a raw material for making plastics * less energy is needed for recycling compared with making a new product from natural resources, so the emission of greenhouse gases is reduced * the amount of waste that isdisposed of in landfill is reduced

Question 27

what is bronze an alloy of, what are it's uses and why is it used for that

Answer 27

* alloy of copper with tin * good for making statues, decorative objects and medals * because it's harder than copper

Question 28

what is gold alloyed with, what are it's uses and why is it used for that

Answer 28

* gold with zinc/ copper/ silver etc. * used to make jewellery * because its harder and cheaper than gold * however a slightly different colour

Question 29

what is alluminium alloy called, what are it's uses and why is it used for that

Answer 29

* magnalium * aluminium has a low density, so pieces of aluminium are relatively lightweight * it is alloyed to make it harder * it is now perfect for aircraft manufacturing

Question 30

what are 3 types of steel (alloys of iron), what are they alloyed with, what are their properties and uses

Answer 30

* High carbon steel- Iron + Carbon- Strong, brittle= for cutting tools/ construction * Low carbon steel- Iron + Carbon- Softer, more easily shaped= for making car body panels * Stainless steel- Iron + Chromium and nickel- Hard, resistant to rusting= cutlery because it does not rust

Question 31

describe the benefits of alloys compared to pure metal

Answer 31

* harder than pure metals * because they're made from atoms of different elements which have different sized atoms * these added atoms distort the layers of metals atoms * making it harder for them to slide over eachother

Question 32

define alloy

Answer 32

a mixture of two or more elements, at least one of which is a metal

Question 33

what are ceramics, what properties does each type have and how do they link to their use? how is each type made?

Answer 33

* non-metallic solids with high melting points that aren't made from carbon-based compounds * there are glass ceramics and clay ceramics * clay ceramics- often coated with a glaze, which hardens on heating to form a hard, smooth, opaque and waterproof layer= used for dinner plates and bowls. * made by shaping wet clay and then heating it to a high temperature in a furnace, which causes crystals to form and join together. * glass ceramics- transparent and hard but it is brittle= windows ( can smash easily) * soda-lime glass made by melting sand, sodium carbonate and limestone, then allowing the molten liquid to cool and solidify. * Borosilicate glass is made by heating sand with boron trioxide- has a much higher melting point than soda-lime glass.

Question 34

what are polymers, what properties does each type have and how do they link to their use?

Answer 34

* very large molecules formed when many small molecule (monomers) join together and are held together by strong covalent bonds in long chains * thermosoftening polymers- made of individual tangled chains of polymers with weak forces in between the chains so they are flexible and can me melted and remolded * they can be recycled * thermosetting polymers- cross-links (covalent or ionic bonds) between polymer chains= polymer doesn't melt when heated, it just chars at a certain point. they are strong, hard and rigid * used to make electrical plugs, which must not melt, even if there is a malfunction and the wiring inside gets hot.

Question 35

what are composites, 2 examples and what properties each example has and how they link to their use

Answer 35

* A composite material consists of two or more materials with different properties. They are combined to produce a material with improved properties. Most composite materials have two components:the reinforcement and the matrix (binds the reinforcement together) * Reinforced concrete (Steel reinforcement, Concrete matrix)- compressive strength of concrete higher than its tensile strength, but the tensile strength of steel is higher than its compressive strength- combination of the two materials that is strong in tension and in compression= reinforced concrete to be strong and slightly flexible= used for constructing large buildings and structures. * Fibreglass (Glass fibres reinforcement and Polymer resin matrix)- The fibres in these composite materials have a low density. They are strong in tension, so they are not easily stretched, but they are flexible. The polymer resin which binds the fibres together is not strong but it is stiff. The composite materials show a combination of these properties. They are strong, stiff and lightweight= used for skis, boats and surfboards

Question 36

what is the haber process?

Answer 36

The industrial chemical process that involves a reversible reaction between nitrogen and hydrogen at dynamic equilibrium to make ammonia. It is often sped up by an iron catalyst to reach equilibrium faster.

Question 37

what is the equation for the haber process?

Answer 37

N2(g) + 3H2(g) ⇌ 2NH3(g) (+heat)

Question 38

what is recycled in the haber process and why?

Answer 38

unreacted nitrogen and hydrogen are recycled because recycling the unused reactants saves money and increases the effective (overall) yield.

Question 39

what are the optimum conditions for the haber process? what does they result in?

Answer 39

low temperature of 350C and high pressure of 400atm = highest possible yield

Question 40

why is 200atm used instead of the optimum pressure of 400atm in industry (haber process)?

Answer 40

* because it is expensive to achieve * dangerous if something goes wrong

Question 41

why is 450C used instead of the optimum temperature of 350C in industry (haber process)?

Answer 41

* because it increases the rate of reaction * this makes it more efficient in industry

Question 42

what happens if the temperature is increased in the haber process?

Answer 42

* the equilibirum moves in the left direction (reactants) * because the reverse reaction is endothermic

Question 43

what happens if the pressure in the system in the haber process is increased?

Answer 43

* the equilibrium moves in the right direction (products) * because there are fewer moles of products

Question 44

what salts are produced when phosphate rock is treated with nitric acid?

Answer 44

Calcium nitrate and phosphoric acid (which is neutralised with ammonia to make ammonium phosphate)

Question 45

what salts are produced when phosphate rock is treated with sulfuric acid?

Answer 45

Single superphosphate (a mixture of calcium sulfate and calcium phosphate)

Question 46

what salts are produced when phosphate rock is treated with phosphoric acid?

Answer 46

Triple superphosphate (calcium phosphate)

Question 47

compare the temperature of industrial production of fertilisers and the laboratory method

Answer 47

* industrial- Different stages require temperatures between 60°C and 450°C * lab- Room temperature for the neutralisation, then heating with a Bunsen burner to evaporate the water

Question 48

compare the equipment and processes of industrial production of fertilisers and the laboratory method

Answer 48

* industrial- Very expensive chemical plant machinery, used in a continuous process * lab- Cheap and versatile laboratory equipment, used in a batch process

Question 49

compare the starting materials of industrial production of fertilisers and the laboratory method

Answer 49

* industry- Reactants are made from raw materials, eg sulfur, air, water * lab- Reactants are purchased from a chemical supplier

Question 50

compare the scale/ yield of industrial production of fertilisers and the laboratory method

Answer 50

* industrial- Huge quantities can be made quickly. * lab- Small quantities are made slowly

Question 51

compare the running costs of industrial production of fertilisers and the laboratory method

Answer 51

* industrial- Automatic control mechanisms and machinery reduces the labour costs and running costs * lab- The method is very labour-intensive, so running costs are high

Question 52

what is an NPK fertiliser?

Answer 52

formulations that supply nitrogen, phosphorus and potassium compounds to promote plant growth.

Question 53

define rusting including what it is an example of

Answer 53

* An example of a corrosion process in which iron or steel reacts with oxygen and water.

Question 54

what is corrosion?

Answer 54

the degradation of metal surfaces happens when a metal continues to oxidise. the metal becomes weaker over time and eventually all of it may become metal oxide.

Question 55

what are 5 ways to prevent corrosion?

Answer 55

* removing substances that cause rusting * physical barriers to oxygen and water * electroplating * sacrificial protection * galvanising

Question 56

3 examples of physical barriers to stop rusting

Answer 56

* painting * oiling and greasing * coating with plastic

Question 57

describe how galvanising works

Answer 57

* When iron is coated in zinc, the process is called galvanisation. * The zinc layer stops oxygen and water reaching the iron. * Zinc is more reactive than iron, so it also acts as a sacrificial metal. * This protection works, even if the zinc layer is scratched.

Question 58

describe how sacrificial protection works?

Answer 58

* Iron can be protected from rusting if it is in contact with a more reactive metal, such as zinc. * The more reactive metal oxidises more readily than iron, so it ‘sacrifices’ itself while the iron does not rust. * Once the sacrificial metal has corroded away, it can simply be replaced.