C10 - Using Resources Flashcards
What do humans use Earth resources for?
- Warmth
- Shelter
- Food
- Transport.
What are some natural resources humans use?
- Minerals
- Fossil fuels
- Water
Define ‘finite’
- Resources that are being used up at a faster rate than they can be replaced
- Limited amount
- Will run out
What are renewable resources?
- Resources that can be replaced at the same rate they are being used up.
- Will not run out
What is ‘sustainable development’?
Development that meets needs of current
generations without compromising the ability of future generations to meet their own needs
Fill in the gaps:
Chemists try to improve ___________ and __________ processes to provide new ________ that allow humans to meet their needs.
- agriculture
- industrial
- products
State an example of a natural product that is supplemented or replaced by an agricultural or synthetic product.
- Fertilisers used to be obtained from manure
- Haber process enabled humans to produce fertilisers from nitrogen in the air
- Has allowed synthetic fertilisers to be produced
Complete the sentences:
1) Water of appropriate quality… is essential for life.
2) Drinking water should have sufficiently low…
1) …is essential for life
2) …levels of dissolved salts
and microbes
What is potable water?
- Water that is safe to drink
- Not pure water –> potable water can still contain dissolved impurities
- must have sufficiently low levels of dissolved salts and microbes
How is potable water produced?
- Rainwater collected form ground, lakes or rivers
- Screens remove large objects
- Aluminium sulfate and lime added –> cause small dirt particles to clump together
- Filter removes remaining particles
- Chlorine/UV light/ozone used to kill harmful bacteria
- pH of water checked and water is stored
What is an alternative method to producing potable water?
Desalination (from seawater):
1. Distillation –> seawater heated until boiled, steam (pure water) collected + cooled + condensed
2. Reverse osmosis - uses membranes
Disadvantages of alternative processes to producing potable water.
Distillation:
- Requires lots of energy
- Difficult to dispose of waste sustainably
Reverse Osmosis:
- Expensive
- Not efficient
What is waste water?
Water that is…
- a product of urban lifestyles and industrial processes
- includes organic matter, harmful microbes and harmful chemicals
- requires treatment before being rereleased into environment
How is waste water treated?
- Screening and grit removal: to remove large particles
- Sedimentation: allows tiny particles to settle out from still water, which produces sewage sludge (sinks) and effluent (floats)
- Sewage sludge is digested anaerobically by specific bacteria
- Effluent is treated with aerobic bacteria to reduce the volume of solid waste
What is phytomining? Evaluate this method.
- Plants are grown on a low-grade ore
- Plants absorb metal ions through their roots and concentrate these ions in their cells
- Plants are harvested and burnt
- Ash left behind contains metal compounds
Disadvantages:
- release CO2 due to burning
- takes long time
- produces lower quality metal
What is bioleaching? Evaluate this method.
Certain bacteria can break down low-grade ores to produce a leachate (acidic solution containing copper ions).
Disadvantages:
- Slow
- Less profit
- Sometimes toxic chemicals can be produced as a results
What are life cycle assessments (LCA)? What are they used for?
Assess the environmental impact of products in different stages (extraction, manufacturing, use and disposal)
What are the benefits of LCA?
- Improved understanding of the environmental impact of a product or process
- Identification of areas where improvements can be made to reduce the impact
- Improved decision-making for more sustainable products and processes
- Better communication of the environmental impact of products and processes to stakeholders
What are the limitations of LCA?
- Difficult to measure environmental impacts
- Time consuming and expensive to gather data
- Require experts
- Companies can misuse LCAs
- Not objective
Describe the LCA of a plastic bag.
Raw Materials:
- Crude oil is a finite resource
- Fractional distillation, cracking and polymerisation all require a lot of energy
Manufacturing:
- Cheaper than paper bags to make large quantities of bags from plastic.
Use:
- Stronger –> can be reused many times
- Lower impact on the environment
Disposal:
- Can sometimes be collected and recycled
- Do not biodegrade in landfill
Describe the LCA of a paper bag.
Raw Materials:
- Can be made from recycled paper/trees.
- Making paper from trees requires more energy than recycling paper, but much less than making plastics.
Manufacturing:
- More expensive to make bags from paper because the handles must be glued on.
Use:
Relatively short lifetime; can only be reused a limited number of times.
Disposal:
- Can be recycled easily
- Biodegrade quickly in landfill
Explain how reusing and recycling reduces energy use.
- 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
- Amount of waste that is disposed of in landfill is reduced
How to reduce the consumption of raw resources. (recycling and reusing)
Glass bottles:
- can be crushed and melted to make different glass products
- can be sterilised
Metals:
- melting and recasting or reforming into
different products
What is corrosion? Give an example.
- Destruction of materials by chemical reactions with substances in the environment.
- Rusting (when iron reacts with water and air)
How do you prevent corrosion?
Applying a coating that acts as a
barrier
- greasing
- painting
- electroplating
What is sacrificial protection? How does it work?
- A metal is coated/covered with a more reactive metal.
- More reactive metal oxidises more readily so the it is ‘sacrificed’
- More reactive metal can be replaced when corroded away.
Describe the benefits of using alloys instead of pure metals.
- Pure meta particles slide over each other as they’re in regular layers making it soft
- Alloys have different sized particles so layers are disrupted so they don’t slide
- Alloys are therefore harder and stronger than pure metals
What are the copper alloys and their uses?
Bronze:
- Copper and tin
- Statues, bells and coins
Brass:
- Copper and zinc
- Musical instruments, door knobs, locks and taps
Gold alloys:
- Usually used as jewellery
- Usually an alloy with silver, copper and
zinc - Proportion of gold in the alloy is measured in carats.
- 24 carat is 100% (pure gold)
- 18 carat being 75% gold
Steel alloys:
Steels are alloys of iron that contain specific amounts of carbon and other metals.
- High carbon steel –> strong but brittle so used in construction
- Low carbon steel –> softer and malleable so used to make car body panels
- Stainless steels (contain chromium + nickel) –> hard and resistant to corrosion so used for cutlery
Aluminium alloys
- Aluminium does not react with water. Its surface is protected by a natural layer of aluminium oxide that allows the metal to resist corrosion.
- Aluminium foil used to store food
- Aluminium has a low density (lightweight)
- Magnalium: alloy of aluminium and magnesium.
- Stronger than aluminium alone but still has a low density
- Used to make aircraft parts.
Properties and uses of glass:
- Most glass we use is soda-lime glass
- Made by heating a mixture of sand, sodium carbonate and limestone.
- Borosilicate glass, made from sand and boron trioxide, melts at higher temperatures than soda-lime glass.
- Glass is transparent and hard but it is brittle
- Glass shatters when it is hit or dropped
Properties and uses of clay ceramics:
- Made by shaping wet clay and then heating in a furnace, which causes crystals to form and join together
- Pottery, bricks, China, porcelain
- Often coated with glaze to make waterproof
Polymers:
- Properties of polymers depend on what monomers they are made from and the conditions under which they are made.
Low density poly(ethene):
- Polymer chains are branched –> molecules are arranged randomly
- Flexible, unreactive, can be made into films
- carrier bags and bubble wrap
High density poly(ethene):
- Less branching of the polymer chains –> molecules line up much more closely.
- Strong, flexible, resists shattering, resists chemical attack
- Plastic bottles, pipes, buckets
Thermosoftening polymers melt when they are heated.
Thermosetting polymers do not melt when they are heated.
What are thermosoftening polymers and Thermosetting polymers?
Thermosoftening polymers melt when they are heated:
- no covalent bonds between polymer molecules
- molecules can move over each other when heated and the plastic melts.
- can be recycled
Thermosetting polymers do not melt when they are heated:
- Resistant to much higher temperatures than thermosoftening plastics
- Used to make electrical plugs
What are composites?
What are the benefits of using them compared to to other materials?
Give examples.
A composite material consists of two or more materials with different properties.
Have two components:
- Reinforcement = makes up bulk of composite material
- Matrix = binds reinforcement together
Produce materials with improved properties
Examples:
- Fibre glass
- Carbon fibre reinforced polymer (CFRP)
- Chipwood
- Reinforced concrete
