C10 : Using Resources

What do humans use the Earth’s resources for? (4)

• Warmth

• Shelter

• Food

• Transport

What is sustainable development?

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

DELETE

Where are finite resources extracted from? (3)

• Earth

• Oceans

• Atmosphere

What are finite resources processed to do? (2)

• Provide energy

• Provide materials

DELETE

Which synthetic product can be used to supplement cotton used for clothing?

Polyester

What is a pure substance?

A pure substance is a single element or compound, not mixed with any other substance

For humans what should water contain?

Low levels of dissolved salts

What is potable water?

Water that is safe to drink

Is potable water a pure substance + why?

No because it contains dissolved substances

What do the methods used to produce potable water depend on? (2)

• Available supplies of water

• Local conditions

Explain how to analyse a sample of water + purify it using distillation (9)

1. Use universal indicator to test the pH of the water

2. Measure and record the mass of an empty evaporating basin

3. Pour 10 cm3 water into the evaporating basin and evaporate the water using a bunsen burner until the most of the water has evaporated

4. Once the evaporating basin is cool, reweigh and record the change in mass

5. Calculate the mass of dissolved solids in the water

6. Place the water sample in a conical flask and set up the apparatus for distillation

7. Heat the water gently using a bunsen burner until it boils. Then reduce the heat so the water boils gently

8. Collect around 1 cm depth of water in the cooled test tube, then stop turn the bunsen burner off

9. You should have distilled water with no other substances and a pH of 7, making it a pure substance

How is potable water produced? (3)

• Choosing an appropriate source of fresh water (either groundwater or surface water)

• Then it is passed through a wire mesh to get rid of large items and then through filter beds to filter out any other solid remains

• Then it is sterilised to kill any harmful bacteria or microbes

What 3 sterilising agents are used for potable water?

• Chlorine

• Ozone

• Ultraviolet light

What is used if supplies of fresh water is limited?

Desalination of salty water or sea water

What are the 2 ways water can be desalinated?

• Reverse osmosis

• Distillation

Explain how desalination of sea/salty water via reverse osmosis works (3)

• Water is put under high pressure and passed through a membrane which has tiny pores (holes) in it

• The pores allow water molecules through, but prevent most ions and molecules from passing through

• This results in potable water

What is the downside to desalination?

Requires large amounts of energy and therefore is very expensive

Why is water waste treated?

So it is safe enough to be released into the environment

What 3 things are removed during waste water treatment?

• Organic matter

• Harmful microbes

• Harmful chemicals

Explain sewage treatment (6)

1. The sewage is first screened, in which large bits of material are removed as well as grit

2. Then it’s put into a settlement tank in which it undergoes sedimentation, the heavier solids sink to the bottom + produce sludge + lighter effluent (liquid waste) sits on top

3. The effluent is removed +water is bubbled through it + treated by biological aerobic digestion in which aerobic bacteria breaks down organic matter + microbes

4. The sludge is removed + transferred to larger tanks, where it is treated via anaerobic digestion, to break down organic matter.

5. Anaerobic digestion releases methane gas which can be used as an energy source and the remaining waste can be used as a fertiliser

6. For waste containing toxic substances, treatment would need the addition of chemicals, UV radiation or membranes

Is metal a finite or renewable resource?

A finite resource

What are the 2 ways metals is extracted from low-grade ores?

• Phytomining

• Bioleaching

Explain how phytomining works to extract metals (4)

• Grow plants in the soil that contains the desired metal

• The metal gradually builds up in the leaves

• The plants are then harvested, dried and burned to produce ash

• The ash produced contains metal compounds which can be extracted by electrolysis or displaced with a more reactive metal (scrap iron)

Explain how bioleaching works to extract metals (2)

• Bacteria are used to convert metal compounds into the ore and a leachate

• The leachate contains metal ions which can be extracted by electrolysis or displaced with a more reactive metal (scrap iron)

Why are life cycle assessments (LCAs) carried out?

To assess the environmental impact of products

What are the 4 stages of life cycle assessments?

• Extracting and processing raw materials

• Manufacturing and packaging

• Use of the product

• Disposal of the product

Explain the 1st step of life cycle assessments : extracting and processing raw materials (2)

• Extracting raw material needed for a product can damage the environment + extraction can also result in pollution because of the energy used

• Raw materials need to be processed which needs energy + that energy could be from fossil fuels

Explain the 2nd step of life cycle assessments : manufacturing and packaging (2)

• Manufacturing products + their packaging can use a lot of energy which causes pollution

• Also waste products could be made + they need to be reused efficiently so the environment is not harmed

Explain the 3rd step of life cycle assessments : Use of the product (2)

• Use of the product could harm the environment e.g. fertilisers harming ecosystems

• Also how long a product is used for: does the energy used to make it equate to how long it is used for

Explain the 4th step of life cycle assessments : product disposal (3)

• Products can be disposed in landfill sites, which takes up space + releases methane

• Energy is needed for these products to transport them to the disposal sites

• Products might be burnt which causes air pollution

Compare the life cycle assessments in terms of the 4 stages for plastic bags + paper bags

Life cycle assessments stages	Plastic bag	Paper bag
Raw materials	Crude oil	Timer/wood
Manufacturing + packaging	Compounds needed for crude oil are extracted from crude oil + waste is reduced as other fractions of crude oils have other uses	Pulped timber is processed using lots of energy + lots of waste is made + cutting down wood leads to deforestation
Using the product	Can be reused many times	Usually only used once
Product disposal	Recyclable but will end up in landfills + pollute land	Biodegradable, non-toxic and can be recycled

What are the problems with life cycle assessments? (3)

• Allocating numerical values to pollutant effects is less straightforward

• Life cycle assessments are not purely objective processes

• Selective or abbreviated life cycle assessments can be devised to evaluate a product in support of claims for advertising purposes

What are the 3 Rs in terms of being sustainable?

• Reduce

• Reuse

• Recycle

What does obtaining raw materials from the Earth by quarrying and mining cause?

Negative environmental impacts

How can glass bottles be reused?

Glass bottles can be crushed + melted to make different glass products

How can metals be recycled?

By melting + recasting or reforming into different products

What does the amount of separation required for recycling depend on?

The material and the properties required of the final product

How is the amount of iron that needs to be extracted from iron ore reduced?

Scrap steel can be added to iron from a blast furnace

What is corrosion?

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

Give an example of corrosion

Rusting

What is needed for iron to rust? (2)

• Air

• Water

How can corrosion be prevented?

By applying a coating that acts as a barrier

What are examples of methods that can be used to prevent corrosion? (3)

• Greasing

• Painting

• Electroplating

What does aluminium have that prevents it from further corroding?

An oxide coating that protects the metal

Give an example of a more reactive metal which provides sacrificial protection to prevent iron from rusting

Zinc, when it is used to galvanise iron

If you put an iron nail in a boiling tube with water + a layer of oil, will the nail rust + why?

No because the oil is used to stop any air getting in

If you put an iron nail in a boiling tube with air + calcium chloride, will the nail rust + why?

No, because the calcium chloride absorbs any water from the air

If you put an iron nail in a boiling tube with air + water will it rust + why?

Yes, because in order for the iron nail to rust there has to be both water + air

What is bronze an alloy of?

Copper + tin

What is brass an alloy of?

Copper + zinc

What is gold which is used in jewellery is an alloy of?

Gold, silver, copper + zinc

What is the proportion of gold in the alloy is measured in?

Carats

How pure is 24 carat gold?

100%

How pure is 18 carat gold?

75%

How pure is 12 carat gold?

50%

How pure is 6 carat gold?

25%

What is steel an alloy of + what does it contain?

• Steel is an alloy of iron

• It contains specific amounts of carbon dioxide, iron, and other metals

What is the main property of high carbon steel?

It’s brittle

What is the main property of low carbon steel?

It’s softer + more easily shaped

What is stainless steel contain + what is it’s main property + how does it react with corrosion?

• Contains chromium + nickel

• Hard

• Resistant to corrosion

What density are aluminium alloys?

Low density

What are the 2 types of ceramics?

• Glass

• Clay ceramics

What are the 2 types of glass?

• Soda-lime glass

• Borosilicate glass

How is soda-lime glass made?

By heating a mixture of sand, sodium carbonate and limestone which is then cooled to produce soda-lime glass

How is borosilicate glass made?

By heating sand and boron trioxide which is then cooled to produce borosilicate glass

What is the main difference between the production of soda-lime glass and borosilicate glass?

Borosilicate glass needs higher temperature compared to soda-lime glass

How are clay ceramics made?

By shaping wet clag and then heating it in a furnace

Give 2 examples of clay ceramics

• Pottery

• Bricks

What are composites?

Materials made up of 2 materials

What are composites made up of? (easy)

A matrix (binder) + a fibre/fragments

What are composites made up of? (hard)

A matrix or binder surrounding and binding together fibres or fragments of the other material, which is called the reinforcement

Give 3 examples of composites

• Fibre glass

• Concrete

• Wood

What is fibreglass made up of + what are its properties?

Made from

• Fragments = Glass

• Matrix = Polymer (plastic)

Properties

• Low density

• Very strong

What is concrete made up of + what are its properties?

Made from

• Fragments = mixture of sand + gravel (aggregate)

• Matrix = cement

Properties

• Very strong

What is wood made up of?

Made from

• Fragments = cellulose fibres

• Matrix = organic polymer

What 2 things do the properties of polymers depend on?

• What monomers they are made from

• The conditions under which they are made

What do the properties of poly(ethene) depend on? (3)

• The catalyst used

• Temperature

• Pressure

Give 2 examples of polymers

• Low density poly(ethene)

• High density poly(ethen)

What is low density poly(ethene) made from + what conditions?

• Made from ethene

• In moderate temperatures + under high pressure

What are the properties of low density poly(ethene) + what is it used for?

• It’s flexible

• Used for bags + bottles

What is high density poly(ethene) made from + what conditions?

• Made from ethene

• In low temperatures + low pressures with a catalyst

What are the properties of high density poly(ethene) + what is it used for?

• It’s rigid

• Used for water tanks + drainpipes

What are thermosoftening polymers contain in terms of structure?

They contain individual polymer chains entwined together with weak forces between the chains

What are thermosetting polymers contain in terms of structure?

They contain monomers that can forms cross-links between polymer chains, holding the chains together in a solid structure

What is the main difference between thermosoftening polymers + thermosetting polymers?

Thermosoftening polymers melt when heated but thermosetting polymers do not melt when heated

In general what are the properties of ceramics? (3)

• Insulators of heat + electricity

• Brittle

• Stiff

In general what are the properties of polymers? (3)

• Insulators of heat + electricity

• Flexible

• Easily moulded

In general what are the properties of composites?

All different because all composites have different materials

In general what are the properties of metals? (5)

• Conductors of heat + electricity

• Malleable

• Ductile

• Shiny

• Stiff

What is the haber process used to manufacture?

Ammonia

What can ammonia be used to produce?

Nitrogen-based fertilisers (ammonium nitrate)

What are the raw materials needed for the haber process?

Nitrogen + hydrogen

What type of reaction is the haber process?

Reversible reaction

What is the balanced symbol equation for the haber process?

How is nitrogen obtained?

From the air

How is hydrogen obtained?

A reaction between methane with steam (which forms hydrogen + carbon dioxide)

What type of reactions are the forwards + backwards reactions in the haber process?

• Forwards = exothermic

• Backwards = endothermic

What type of catalyst is used in the haber process?

An iron catalyst