Topic 10

Question 1

Natural resources

Answer 1

• Form without human input
• Anything that comes from the earth, sea, or air
• Some can be replaced with synthetic products e.g. rubber for man made polymers
• ## Agriculture provides conditions to enhance natural resources e.g. fertilisers = high yield of crops

Question 2

Finite resources

Answer 2

• Renewable resources reform at a similar rate to, or faster, then we use then e.g. timber, fresh water, food
• Finite are not formed fast enough to be considered replaceable e.g. fossil fuels, nuclear fuels, minerals & metals
• Many finite resources undergo man-made processes eg. fractional distillation, reduction
• Most plastics, metals, & building materials are made from finite resources
• Pros of extracting finite = making useful products, provides local people with jobs & money. Cons = uses energy, scars the landscape, produces waste & destroys habitats

Question 3

Sustainable development

Answer 3

• Takes into account the needs of present society while not damaging future generations

Question 3

Sustainable development

Answer 3

• Takes into account the needs of present society while not damaging future generations

Question 4

Sustainability of copper

Answer 4

• Finite resource
• Sustainability improves by extracting it from low grade ores
• Bioleaching: bacteria convert copper compounds in the ore into soluble copper, separating out the copper. The leachate contains copper ions which can be extracted by electrolysis or displacement
• Phytomining: growing plants in copper-containing soil. Plant builds up copper; it can be harvested, dried, and burned. Ashes contain soluble copper compounds which can be extracted by electrolysis or displacement
• Disadvantage of both is that they are slow

Question 5

Recycling metals

Answer 5

• Mining and extracting metals uses lots of energy, most of which comes from burning fossil fuels
• Recycling metals uses much less energy, conserves finite amount, and cuts down the amount of waste sent to landfill
• Metals are usually recycled by melting them & casting them into the shape on the new product
• Depending on type of metal, amount of separation required can change e.g. waste steel & iron can be kept together and added to iron in blast furnace to reduce amount of iron ore

Question 6

Recycling glass

Answer 6

• Reduces amount of energy needed to make new glass products, & amount of waste created
• Glass bottles can often be reused without reshaping
• Forms of glass that cannot be reused are recycled; usually glass is separated by colour and chemical composition

Question 7

Recycling glass

Answer 7

• Reduces amount of energy needed to make new glass products, & amount of waste created
• Glass bottles can often be reused without reshaping
• Forms of glass that cannot be reused are recycled; usually glasses are separated by colour and chemical composition
• Glass is crushed & melted to be reshaped

Question 8

LCA

Answer 8

• ## Life Cycle Assessment looks at every stage of a product’s life to assess the environmental impact

Question 9

Potable water

Answer 9

• Water that is safe for humans to drink
• Not pure: Pure only contains H2O molecules, potable contains lots of other dissolved substances
• Important that levels of dissolved substances are not to high, ph 6.5-8.5, there are not any bacteria or other microbes

Question 10

Production of potable water

Answer 10

• Water is collected either as surface water (lakes, rivers, reservoirs) or groundwater (aquifers)
• In UK, source of freshwater depends on location
• Freshwater is treated with filtration (wire mesh screens out large twig, gravel and sand beds filter out other solid bits) then sterilisation (sterilised kill harmful bacteria by bubbling chlorine gas, or ozone or UV)
• In dry countries seawater must be treated by desalination (Distillation)
• Seawater can also be treated with reverse osmosis (…)
• Both distillation & reverse osmosis need lots of energy, so expensive and impractical for large quantities of freshwater

Question 11

Wastewater

Answer 11

• Comes from sewage from domestic sources, agriculture systems, industrial processes,
• Sewage treatment happens in stages: screening, sedimentation, treated with biological aerobic digestion, anaerobic digestion, additional treatment with chemicals, UV radiation, or using membranes
• Sewage treatment uses less energy then desalination