Using Resources

Question 1

What do you need for rusting

Answer 1

• iron
• oxygen
• water

Question 2

What’s sacrificial protection

Answer 2

Attaching a more reactive metal so the more reacted metal will get corroded
= protect iron from rusting

Question 3

Adv and dis of purifying sea water by reverse osmosis

Answer 3

Can get fresh water from sea water
Expensive as uses a lot of energy

Question 4

Why use alloys not pure metals

Answer 4

Alloys are harder and cheaper
Pure metals are softer

Question 5

What’s corrosion

Answer 5

Chemical reaction
Eg rusting

Question 6

Where does natural rubber come from

Answer 6

Sap of a tree
= produced using crude oil

Question 7

Define finite

Answer 7

Can’t be replaced as quickly as they’re being used
Eg fossil fuels

Question 8

How does chemistry help

Answer 8

We can use artificial fertilisers
= grow more food with the land available
Water that’s safe to drink

Question 9

Describe drinking water

Answer 9

Must have low levels of dissolved salts
Eg sodium chloride
Can’t have high levels of microbes
Eg bacteria

Question 10

Define potable water

Answer 10

Water that’s safe to drink

Question 11

How to we collect rainwater

Answer 11

Collected from ground in aquifers and in lakes, rivers and reservoirs

Question 12

Why do we use rainwater

Answer 12

Contains low levels of dissolved substances

Question 13

How to produce potable water

Answer 13

• choose food source of fresh water
  Eg a river
• pass water through filter beds
  = removes materials like leaves
• water is sterilised to kill microbes
• in uk we use chlorine

Question 14

Describe sea water

Answer 14

Very high levels of dissolved minerals
= potable water produced by desalination

Question 15

Describe desalination

Answer 15

Reduces the levels of dissolved minerals down to an acceptable level for potable water

Question 16

How to carry out desalination

Answer 16

Use distillation or reverse osmosis
= both reduce levels of dissolved minerals
= both require very large amounts of energy
= very expensive

Question 17

Effect of calcium chloride

Answer 17

Remove any water vapour from air

Question 18

Describe iron corrosion

Answer 18

Top layer rusts and then falls off
= reaches another layer and repeats

Question 19

Describe aluminium corrosion

Answer 19

Only surface atoms are affected
Creates aluminium oxide
= forms protective layer against environment

Question 20

How to prevent iron rusting

Answer 20

• prevent oxygen and water touching iron
  Eg paint iron, oil or grease iron, electroplating
• adding more reactive metal like aluminium or zinc to the iron
  = if object exposed to oxygen more reactive metal will be oxidised instead

Question 21

How are metals recycled

Answer 21

Separate metals into elements and melt and reform

Question 22

How is glass recycled

Answer 22

Seperated and crushed then melted

Question 23

Stages of lifecycle assessment

Answer 23

• extracting and processing raw materials
• manufacturing and packaging product
• using product
• disposing product

Question 24

Limit of lifecycle assessment

Answer 24

• so complex so can be manipulated to deliberately support a company
  = hard to notice

Question 25

Describe pure water

Answer 25

Only has h2o molecules

Question 26

Criteria for potable water

Answer 26

- levels of dissolved substances must be low - pH of 6.5-8.5 - no micro organisms like bacteria or fungi

Question 27

Adv and dis of surface water

Answer 27

Easy to access Replaced frequently by rain Can dry up from sun

Question 28

How to treat fresh water

Answer 28

- fresh water goes through wire mesh to filter out big things like twigs - pass it out through bed of sand and gravel to filter out small solid bits - sterilise it to kill harmful microbes like bacteria Can be done by: - bubbling chlorine gas through it - exposing it to ozone or ultra violet light

Question 29

Describe desalination

Answer 29

Extract potable water from sea water Really expensive as requires loads of energy and impractical

Question 30

Describe reverse osmosis

Answer 30

- salty water passed through membrane that only allows water molecules to pass through = means ions and larger molecules get trapped and separated from the water = makes pure distilled water

Question 31

How sewage treatment works

Answer 31

- screening sewage to remove anything large like twigs or bottles ( passing sewage though a mesh) - let sewage sit in sediment tank = undergo sedimentation ( heavier solids sink to bottom to form sludge) - left with effluent at top - separate into separate tanks - breakdown matter by biological breakdown by microbes - effluent aerobic conditions = pump air into tank - sludge anaerobic conditions = keep tank sealed so little or no oxygen can get through = produces methane so but be captured and burned as energy source and remaining waste used as fertiliser

Question 32

How to remove toxic substances

Answer 32

Adding chemicals Ultra violet radiation

Question 33

Reasons for using gold in industrial production

Answer 33

gold is the only catalyst for some reactions catalysts are not used up improves speed of reaction reduces amount of energy

Question 34

Examples of earths resources and uses

Answer 34

Trees = timber and fuels Wood chips = power stations run on biofuels Natural rubber comes from sap of a tree

Question 35

Describe synthetic rubber

Answer 35

Made of crude oil

Question 36

Describe finite

Answer 36

Can’t be replaced as quickly as being used Eg fossil fuels

Question 37

Describe process of waste water treatment

Answer 37

- sewage is screened by passing through a mesh - this removed solids and pieces of grit - now sewage can settle in large sedimentation tanks = produces liquid effluent and a semi sludge which sinks - sludge taken away and digested by anaerobic bacteria - in absence of oxygen these bacteria produce biogas which can be burned for electricity - at end digested sludge used as fertilisers for farming

Question 38

How to reduce toxic chemicals in liquid effluent

Answer 38

- air is bubbled though liquid effluent = allows aerobic bacteria to multiply - in presence of oxygen bacteria digest organic molecules and harmful microorganisms - after this liquid effluent can be safely discharged into near rivers or sea

Question 39

Easiest way to produce potable water

Answer 39

Use ground water from aquifers

Question 40

Dis of desalination

Answer 40

Requires a lot of energy = very expensive

Question 41

How to make an alloy

Answer 41

Melting our metals and mixing in other elements = allow alloy to cool