Chemistry – Key Topic 10
4.10 Using resources
4.10.1 Using the Earth’s resources and obtaining potable water
4.10.1.1 Using the Earth’s resources and sustainable development
Humans use the Earth’s resources to provide warmth, shelter, food and transport
Natural resources, supplemented by agriculture, provide food, timber, clothing and
fuels
- Includes cotton for clothing or oil or fuel
- Some of these natural products can be replaced by synthetic products or improved
upon by man-made processes. E.g. rubber is a natural product that can be
extracted from the sap of a tree, however, man made polymers have now been
made which can replace rubber in uses such as tyres
Finite resources from the earth, oceans and atmosphere are processed to provide
energy and materials. They aren’t formed quickly enough to be considered
replaceable. E.g. fossil fuels and nuclear fuels such as uranium and plutonium
- Many modern materials are made from raw, finite resources, and we need to
balance the social, economic and environmental effects of extracting them
Mining metal ores is good because useful products can be made. It also provides
local people with jobs and money. However, it is bad for the environment as it
uses loads of energy, scars the landscape, produces lots of waste and destroys
habitats
Renewable resources form at a similar rate or faster than we use them e.g. timber as
trees can be planted following a harvest. Also fresh water and food
Chemistry plays an important role in improving agricultural and industrial processes
to provide new products and in sustainable development.
- this is the development that meets the needs of current generations without
compromising the ability of future generations to meet their own needs
- extracting resources can also be unsustainable due to the amount of energy used
and waste produced
- if people reduce how much of a finite resource they use, it is more likely to last
longer
, - chemists can develop and adapt processes that use lower amounts of finite
resources and reduce damage to the environment e.g. they have developed catalysts
that reduce the amount of energy required for certain industrial processes
4.10.1.2 Potable water
Water of appropriate quality is essential for life. For humans, drinking water should
have sufficiently low levels of dissolved salts and microbes. Water that is safe to drink
is called potable water. Potable water is not pure water in the chemical sense because
it contains dissolved substances
The methods used to produce potable water depend on available supplies of water
and local conditions
In the UK, rain provides water with low levels of dissolved substances(fresh water)
that collects in the ground and in lakes and rivers, and most potable water is
produced by:
- Choosing an appropriate source of fresh water
- Passing the water through filter beds – prepared layers of sand. Different sized
insoluble solids are removes as the water trickles through the filter beds
- Sterilising – exposed to chlorine, ozone and UV light which kills microbes that
could cause fatal diseases
If supplies of fresh water are limited, desalination of salty water or sea water may be
required.
Desalination is the process of removing the dissolved substances from water.
Desalination can be done by distillation or by processes that use membranes such as
reverse osmosis. These processes require large amounts of energy and is not practical
for producing large quantities of fresh water
- Distillation is a process that can be used to separate a pure liquid from a mixture
- Distillation separates salt and water by heating and evaporating it, then the water
moves along the condenser turning into pure water
- In reverse osmosis pressure is applied to push water through a semipermeable
membrane from low to high concentration. The membrane is designed to prevent
the largest solutes from passing through. This process requires a lot of energy and
is expensive and the membranes become clogged with bacteria and deteriorate
when sterilised with chlorine.
4.10.1.3 Waste water treatment
4.10 Using resources
4.10.1 Using the Earth’s resources and obtaining potable water
4.10.1.1 Using the Earth’s resources and sustainable development
Humans use the Earth’s resources to provide warmth, shelter, food and transport
Natural resources, supplemented by agriculture, provide food, timber, clothing and
fuels
- Includes cotton for clothing or oil or fuel
- Some of these natural products can be replaced by synthetic products or improved
upon by man-made processes. E.g. rubber is a natural product that can be
extracted from the sap of a tree, however, man made polymers have now been
made which can replace rubber in uses such as tyres
Finite resources from the earth, oceans and atmosphere are processed to provide
energy and materials. They aren’t formed quickly enough to be considered
replaceable. E.g. fossil fuels and nuclear fuels such as uranium and plutonium
- Many modern materials are made from raw, finite resources, and we need to
balance the social, economic and environmental effects of extracting them
Mining metal ores is good because useful products can be made. It also provides
local people with jobs and money. However, it is bad for the environment as it
uses loads of energy, scars the landscape, produces lots of waste and destroys
habitats
Renewable resources form at a similar rate or faster than we use them e.g. timber as
trees can be planted following a harvest. Also fresh water and food
Chemistry plays an important role in improving agricultural and industrial processes
to provide new products and in sustainable development.
- this is the development that meets the needs of current generations without
compromising the ability of future generations to meet their own needs
- extracting resources can also be unsustainable due to the amount of energy used
and waste produced
- if people reduce how much of a finite resource they use, it is more likely to last
longer
, - chemists can develop and adapt processes that use lower amounts of finite
resources and reduce damage to the environment e.g. they have developed catalysts
that reduce the amount of energy required for certain industrial processes
4.10.1.2 Potable water
Water of appropriate quality is essential for life. For humans, drinking water should
have sufficiently low levels of dissolved salts and microbes. Water that is safe to drink
is called potable water. Potable water is not pure water in the chemical sense because
it contains dissolved substances
The methods used to produce potable water depend on available supplies of water
and local conditions
In the UK, rain provides water with low levels of dissolved substances(fresh water)
that collects in the ground and in lakes and rivers, and most potable water is
produced by:
- Choosing an appropriate source of fresh water
- Passing the water through filter beds – prepared layers of sand. Different sized
insoluble solids are removes as the water trickles through the filter beds
- Sterilising – exposed to chlorine, ozone and UV light which kills microbes that
could cause fatal diseases
If supplies of fresh water are limited, desalination of salty water or sea water may be
required.
Desalination is the process of removing the dissolved substances from water.
Desalination can be done by distillation or by processes that use membranes such as
reverse osmosis. These processes require large amounts of energy and is not practical
for producing large quantities of fresh water
- Distillation is a process that can be used to separate a pure liquid from a mixture
- Distillation separates salt and water by heating and evaporating it, then the water
moves along the condenser turning into pure water
- In reverse osmosis pressure is applied to push water through a semipermeable
membrane from low to high concentration. The membrane is designed to prevent
the largest solutes from passing through. This process requires a lot of energy and
is expensive and the membranes become clogged with bacteria and deteriorate
when sterilised with chlorine.
4.10.1.3 Waste water treatment
