10.2.1 Life cycle assessment (LCAs)
Life cycle assessments (LCAs) are carried out to assess the environmental impact of products in each of these stages:
- Extracting and processing raw materials
- Manufacturing and packaging
- Use and operation during its lifetime
- Disposal at the end of its useful life, including transport and distribution at each stage
Disposable cups are made from coated paper or poly(styrene).
The table below shows information on the life cycle assessments (LCAs) of disposable cups.
Evaluate the use of coated paper compared with poly(styrene) to make disposable cups.
Use the table above and your knowledge and understanding of LCAs. (6)
Raw materials
- Crude oil finite or will run out (so will be unavailable for other uses)
- Wood is a renewable resource
- Wood involves land use for forestry (so less available for agriculture / food)
- Wood may involve deforestation (so reduces biodiversity)
Manufacturing
- Both require energy which may be derived from finite fuels (so they run out more quickly)
- Paper more energy intensive (so more pollution is possible)
- The need for more energy for paper potentially releases more carbon dioxide to the atmosphere (so increases global warming)
- Paper involves higher water usage (so increases the potential for water pollution)
- Paper cups are heavier to transport (so have higher energy requirement)
- Packaging requirements similar (so neither has an advantage)
Usage
- Both single-use (so neither has an advantage)
Disposal
- Paper releases more energy if incinerated (so more energy can be used for other purposes)
- Paper will decompose (so will not remain in landfill)
- Poly(styrene) could release toxins on incineration
- Poly(styrene) will not decompose (so will remain in landfill)
- Poly(styrene) can be used to manufacture other products (so conserves energy or finite resources)
- Both can cause litter or visual pollution
Evaluate the production and use of bottles made from soda-lime glass and those made from HD poly(ethene). Use the information given and your knowledge and understanding to justify your choice of material for milk bottles. (6)
- Glass – 2 stages in production of soda-lime glass
- Glass – second stage, heating sand, limestone and sodium carbonate
- HDPE – 3 stages in production
- HDPE – second stage, cracking of naphtha to obtain ethene
- HDPE – third stage, polymerisation of ethene
- Fewer stages in glass production, may be quicker
- Higher temperature in glass manufacture, therefore maybe higher energy requirement
- Glass bottle can be reused
- Consideration of collection / cleaning costs to reuse glass bottles
- Other glass products can be made from recycled glass
- Plastic has greater range of sizes
- Both produced from limited raw materials
- Higher percentage recycled materials in glass conserves raw materials
10.2.2 Ways of reducing the use of resources
- ↓ use, reuse & recycling by end users
- ↓ use of limited resources, energy sources, waste & environmental impacts
Obtaining raw materials from the Earth by quarrying & mining causes environmental impacts
Give two reasons why quarry (and mining) is bad for the environment (2)
- Visual, noise, dust pollution
- Habitat destruction
Some products can be reused
- Glass bottles can be crushed & melted to make different glass products
Other products cannot be reused → so recycled for different use
- Metals can be recycled by melting & recasting / reforming into different products
Why should we recycle? (2)
- Save / conserve resources & energy
- Limited landfill space
- Less CO2 emission & quarrying / mining
Suggest how local council could encourage recycling? (1)
- Provide recycling bins
- Provide education of need to recycle
How is energy saved by recycling more plastics? (1)
- Less energy used
Amount of separation required for recycling depends on material & properties required of the final product
Scrap steel can be added to iron from blast furnace to reduce amount of iron needed to be extracted from iron ore
Why disposing plastic containers in a landfill site could cause problems? (3)
- Landfill sites are limited
- Could be recycled / reused
- Plastic is non-biodegradable
Extraction of iron
How is iron extracted? (2)
- By heating mixture of Fe2O3 in blast furnace
Equation
Iron oxide + carbon → iron + carbon dioxide
2Fe2O3(s) + 3C(s) → 4Fe(s) + 3CO2(g)
Name of the type of reaction (1)
- Reduction
Give 2 reasons why iron produced in a blast furnace is converted into steel (2)
- Iron from the blast furnace is brittle
- Steel produced is strong / flexible / has more uses / rust-resistant