Chemistry ✿ using resources

finite (non-renewable) resource

a natural resource that exist in limited quantities and cannot be replenished quickly (e.g. fossil fuels, ores)

renewable resource

are natural resources that can be replenished naturally over time (e.g. wood)

state 2 examples of natural products that are supplemented or replaced by agricultural and synthetic products

• rubber from trees are now supplemented by synthetic rubber made by man-made polymers

• ethanol and biodiesel from crops are now replaced by fossil fuels

potable water

water that is safe for humans to drink but contains dissolved substances

pure water

water that only has H₂O molecules

fresh water

water that has low levels of dissolved substances and is collected from the ground (rivers or lakes)

In the UK, potable (drinking) water is produced from different sources of fresh water.

Explain how potable water is produced from fresh water. [4]

• find a source of fresh water like a river

• pass water through filter beds to remove undissolved solids

• sterilise using chlorine

• to remove harmful microbes

give examples of 3 sterilising agents

• chlorine

• ozone

• UV light

A different country has:

• very little rainfall

• a long coastline

• plentiful energy supplies

Suggest 2 process this country could use to obtain most of its potable water.

• distillation

• or reverse osmosis

Desalination

the process of removing salt and impurities from seawater by distillation or reverse osmosis

Water obtained by distillation does not need to be sterilised and is safe to drink.

Suggest why

distilled water is pure

suggests one disadvantage of using desalination by reverse osmosis/ distillation

requires a lot of energy

phytomining

the process of burning plants to produce ash which contains metal compounds

Bioleaching

the use of bacteria to produce leachate solutions that contain metal compounds

how are metal compounds processed to obtain the metal?

by displacement using scrap iron or electrolysis