C10- using resources

what are natural resources

resources that form without human input. they include anything that comes from the earth, sea or air

what is a finite resource

finite (non renewable) resources aren’t formed quickly enough to be considered replaceable. Finite resources include fossil fuels and nuclear fuels. After they’ve been extracted many finite resources undergo man made processes to provide the fuels and materials.

2 ways of sustainably extracting copper from ores

1. Bioleaching - bacteria are used to convert copper compounds in the ore into soluble copper compounds, separating out the ore in the process. the solution produced by the process contains copper ions, which can be extracted by electrolysis

2. Phytomining - this involves growing plants in soil that contains copper. The plants cant use or get rid of the copper so it gradually builds up in the leaves. the plants can be harvested, dried and burned in a furnace. the ash contains copper compounds which can be extracted

how are metals recycled

by melting and casting them into the shape of a new product.

how is glass recycled

1. seperated by colour and chemical composition

2. crushed

3. melted to be reshaped

what is the life cycle assessment

it looks at every stage of a products life to assess the impact it would have on the environment

stage 1 of the life cycle assessment

getting the raw materials

extracting raw materials needed for a product can damage the local environment

raw materials often need to be processed to extract the desired materials and this often needs large amounts of energy.

stage 2 of the life cycle assessment

Manufacture and packaging

this can use a lot of energy resources and can also cause a lot of pollution

stage 3 of the life cycle assessment

using the product

the use of the product could damage the environment. for example burning fuels releases fossil fuels, fertilisers can leach into streams and rivers causing damage to ecosystems

how long it is used for and how many uses it gets is also a factor

stage 4 of the life cycle assessment

product disposal

products are often disposed of in landfill sites. This takes up space and pollutes land and water.

energy is used to transport waste to landfill which causes pollutants to be released into the atmosphere.

what is potable water

water that has been treated or is naturally safe for humans to drink.

chemists wouldn’t call it pure because pure water only contains h₂0 molecules where as potable water contains lots of other dissolved substances

how is fresh water treated to be safe to drink

1. filtration - a wire mesh screens out large twigs etc, and then gravel and sand beds filter out any other solid bits

2. sterilisation - the water is sterilised to kill and harmful bacteria or microbes. this can be done by bubbling chlorine gas through it or by using ultraviolet

how can seawater be treated to provide potable water

distillation

sewage treatment process

1. screened - involves removing large bits of material

2. sedimentation - the heavier suspended solid sink to the bottom to produce sludge while the lighter effluent float on top

3. the effluent is removed and treated by aerobic digestion

4. the sludge is removed and transfered into large tanks where it gets broken down in anaerobic digestion.