Resources Flashcards
What is the purpose of a life cycle assessment?
To assess the environmental impact of production
Life Cycle Assessments
- extracting and processing raw materials
-manufacturing and packaging - use and operation during its lifetime
- disposal
each stage: distributed and transportation
Problems with LCA’s
- hard to quantify
- companies may alter LCA’s to support claims
Ways to reduce the use of resources
- reduce
- reuse
- recycle
Recycling benefits
- To reduce the use of limited resources
- reduce waste and environmental impacts
- reduce energy consumption
How to produce a new glass bottle when recycling
crush and melt to produce new glass products
Benefits of reusing, reducing and recycling
quarrying and mining is reduced
corrosion
The destruction/decaying of material caused by chemical reactions with substances in the environment
eg of corrosion
Iron reacts with cold air and water
Using barriers
- paint
- grease
- galvanising, sacrificial
- electroplating
Galvanising
- Using a more reactive metal to protect your material
- The more reactive metal will react. Sacrificial –> donate electrons,
The reactivity series
The ability for metals to lose electrons to form a positive ion
What do humans use the earth’s resources for?
To provide warmth, shelter, food and transport
Why do you use a metal in filters?
It kills microorganisms
Living natural resources
Plants and animals
Non-living natural resources
minerals, fossil fuels, water and air
What resources can be replaced by synthetic products?
Rubber and fertilisers
Rubber
- Rubber, which is extracted from the sap of trees (called latex) is an example of a natural product that can be replaced by a synthetic one.
- The replacement material for rubber are polymers which have been developed to specifically replace the rubber in many products.
Fertilisers
- in some areas, the appliance of scientific advancement has also allowed us to maximise the production of natural products
eg: use of fertilisers.
What can natural resources be classified as?
Either renewable or non-renewable
Renewable resources
Resources which can be replenished or replaced in a finite time in a human timescale.
What is an example of a renewable resource?
Timber, as trees and forests can be replanted after the wood has been harvested, although they do take years to replenish
What are finite or non-renewable resources?
They don’t reform quickly enough or don’t reform at all
eg: minerals from the Earth’s crust and metal ores
What can make the extraction process less sustainable?
Many resources require further processing to make the desired products after extraction- they require energy.
Examples of unsustainable extraction processes
- the reduction of metals from ores
- the fractional distillation of crude oil
What are the risks of the extraction of non-renewable resources?
The Earth’s natural resources are being depleted and large amounts of energy are being consumed in the process of extraction.
What can we do to reduce the need to further exploit finite mineral resources?
Recycle and re-use materials.
Non-renewable resources and finite resources are the
same
What is potable water?
It is water that has been processed and is safe for human consumption and daily use.
What is the difference between pure water and potable water?
Pure water is solely made up of H20 molecules whereas potable water usually contains dissolved minerals and salts.
What characteristics does potable water need to have?
- it has to have a pH between 6.5 and 8.5.
- The dissolved substances (eg: salts) will be present in very small regulated quantities
- Be free of bacteria or potentially harmful microbes.
When is water considered fresh?
When it is relatively free from dissolved substances eg: rainwater
What is surface water?
Water which can collect in reservoirs, lakes and rivers
What is groundwater?
Water which can collect in aquifers which are porous rocks that store water underground.
What does the origin of fresh water depend on?
The climate of the region
How do you treat water?
1, Filtration
- Debris is removed by a wire mesh screen
- After this, other debris is filtered through sand beds and gravel
2, Sterilisation
- Ultraviolet light and ozone is used to sterilise water or chlorine gas is bubbled through the water
- This removes any dangerous bacteria or microbes
What process is used to provide potable water when aquifers are not present and/or the collection of surface water is limited?
desalination
How does desalination work?
- it involves the treatment of seawater to remove the salt by distillation or reverse osmosis, a process that involves the use of membranes
- When salt water is put through a semi-permeable membrane, only water molecules can pass through it. This happens as the membrane stops larger molecules and ions passing through
Where is desalination used?
In regions with a very hot climate such as Saudi Arabia
What is the disadvantage of desalination?
It is an expensive process as it consumes large amounts of energy and is not ideal when producing large quantities of fresh water.
What does the way in which potable water is prepared and delivered to a population largely depend on?
The local conditions of geology.
What happens to water when you run it down a drain?
It passes through sewers and then finally to sewage treatment plants
What produces an abundance of waste water?
- domestic activities- washing dishes etc.
- agricultural waste from animal farms and nutrient run-off which is collected from fields
Why does domestic and agricultural sewage need to be processed?
To remove particulates, toxins and any harmful bacteria and microbes so it can be safely returned to freshwater sources like rivers and lakes.
If domestic and agricultural sewage was not processed, what would happen?
It could potentially pose health risks for the population.
What should happen to waste water produced by the Haber process?
It needs to be gathered and treated properly.
What is present in industrial waste?
Harmful chemicals and organic matter
What has to happen to industrial waste to ensure it is safe for the environment?
Additional treatment
Sewage treatment
-Screening & Grit Removal
The first stage of treatment removes large materials such as plastic bags and twigs and grit by screening
-Sedimentation
Sedimentation comes next which occurs in a settlement tank. The water is allowed to stand still in the tank while heavier solids sink to the bottom creating a sludge, whilst lighter matter which is also known as effluent, floats to the top
-Aerobic Digestion
The effluent is removed and treated by biological aerobic digestion
This involves pumping air into the water to encourage the breakdown of organic matter and other microbes by aerobic bacteria
-Anaerobic Digestion
Anaerobic digestion is then used to break down the sludge from the bottom of the settlement tank. It is firstly removed and placed in large tanks where bacteria break it down
Anaerobic digestion releases methane gas as a by product from the organic matter in the sludge. Methane gas is used as a source of energy and the leftover, digested waste as a fertiliser.
What do you do when there are toxic substances within waste water?
- you have to use additional phases of treatment
- this can include using membranes, adding additional chemicals eg:to precipitate metals out of solution,and also U.V radiation
Where is sewage water often treated?
-Sewage water is often treated in areas where there is little freshwater available
Though this process is longer than processing and preparing freshwater, it uses less energy than the desalination of salt water.
When is the extraction of metal ores from the ground economically viable?
When the ore contains sufficiently high proportons of the useful metal, such as iron ores and aluminium ores.
Why are other techniques being developed to meet global demand of nickel and copper?
Their ores are becoming relatively more and more scarce.
What are two relatively new methods of extracting metals that rely on biological processes?
Phytoextraction and bioleaching.
What do the Earth’s resources include?
They include: - rocks in the ground - fuels such as coal, oil and natural gas found underground - plants and animals (produced by agriculture) - fresh water and sea water - air - sunlight -wind
Where does oxygen come from?
Air
Where does water come from?
Rain
Where does food come from?
Plants and animals
Where do clothes come from?
Fibres made from chemicals in oil (eg: nylon, polyesters) or from natural fibres from plants (eg:cotton) or animals (eg:wool)
Where does shelter/buildings come from?
Building materials include: stone, sand, bricks made from clay, cement made from limestone and clay, timber from trees.
Where does warmth come from?
Burning fuels (eg: coal, oil, gas, biofuels from plants).
Where does electricity come from?
It is generated using fuels (eg: coal, oil, gas, biofuels from plants), wind, sunlight, waves, decay of radioactive substances etc.
Where does fuel for transport come from?
Burning fuels (eg: oil, natural gas, biofuels from plants)
Where do medicines come from?
They are mainly made from chemicals found in oil and/or plants
Where do fertilisers come from?
From plant and animal waste or made from nitrogen in the air, water, natural gas and minerals from the ground.
Where do metals come from?
Made from ores in the ground
Where do polymers (plastics) come from?
They are mainly made from chemicals found in oil.
What is corrosion?
It is the destruction of materials by chemical reactions with substances in the environment.
What is rusting?
It is the corrosion of iron or steel.
When do many metals corrode?
When they come into contact with oxygen and/or water.
What is rusting?
It is specifically the corrosion of iron or steel.
What happens when iron corrodes?
It reacts with oxygen and water to produce rust.
What happens when a closed test tube has anhydrous calcium chloride and a nail?
Anhydrous calcium chloride absorbs any water so there is no water present and therefore no rust.
What happens to the nail when it is placed in a closed test tube with cooled boiled water and a layer of oil to keep the air out?
When water is boiled all the dissolved gases escape and so there is no dissolved oxygen in the water in this stoppered tube.
What happens when an iron nail is placed in a stoppered test tube with water
The nail rusts because it comes into contact with water and air.
What is sacrificial protection?
Preventing a metal from corrosion by attaching itto a more reactive that corrodes in its place ( zinc is used a lot)
What are two basic ways to prevent corrosion?
Put a coating on the surface of the metal to act as a protective layer or use sacrificial protection where a more reactive metal is attached to the metal.
