Using Resources Flashcards
What are natural resources?
We get natural resources from the environment and they provide us shelter, food, warmth, etc.
They can be living, (plants and animals)
They can be non-living (water, minerals, fossil fuels, air, etc)
Example of a natural resource which can be replaced synthetically
RUBBER can be extracted from the sap of trees and is a natural product that can be REPLACED BY A SYNTHETIC ONE, which are polymers designed to specifically replace the rubber
What are renewable resources?
Resources which can be replenished or replaced in a finite time
What are non-renewable resources?
Resources which cannot be replenished and are replaced not at all or not quickly enough
What is potable water?
Water that has been processed and is safe for human consumption and daily use
What is the difference between potable water and pure water?
Pure water consists only of H2O molecules, but potable water may consist of different substances, such as dissolved minerals.
What characteristics should potable water have?
- It must have a pH between 6.5 and 8.5
- The dissolved substances will be present in very small regulated quantities
- Be free of bacteria or potentially harmful microbes
What is surface water?
Water which is collected in reservoirs, lakes and rivers
What is groundwater?
Groundwater is water that is stored underground in POROUS rocks called AQUIFIERS
What are aquifiers?
Porous rocks which store water underground
What are two important steps to make sure GROUNDWATER is potent?
Filtration - where debris such as soil and dirt and maybe small pebbles are removed by a WIRE MESH, then smaller debris is filtered through sand beds and gravel
Sterilisation - UV light and ozone is used to sterilise water or chlorine gas is bubbled through the water to remove bacteria or microbes
What is a treatment for water in the case where aquifers are not present or if the collection of surface water is limited?
DESALINATION - Involves the treatment of seawater to remove the salt by DISTILLATION or REVERSE OSMOSIS
When salt water is put through a semi-permeable membrane, only water molecules can pass through it, which separates the two
However desalination is a very expensive process and it consumes large amounts of energy and is not ideal when producing large quantities of fresh water
What is Required Practical 8(a)?
Analysis & Purification of Water Samples
Objective - to determine the mass of dissolved substance in samples of water
Hypothesis - Analysis of the pH and dissolved solids of water samples can help determine the regions the water comes from
Method:
- Use the universal indicator paper to determine the pH of the water sample
- Accurately weigh an empty evaporating basin to two decimal places
- Add 25 cm3of water sample A into the evaporating basin
- Heat the evaporating basin on a tripod and gauze using a Bunsen burner until the solids start to form and the majority of water has evaporated
- Weigh the cooled evaporating basin again and calculate the mass of the solids that were dissolved in the water.
Evaluation:
The results could be compared to the national water safety levels and by analysis the regions of each sample could be deducted e.g. region of high acid rain, water from a salt water supply etc.
Conclusion:
The amount of dissolved solids in water can be determined and is a useful indicator of water quality
What is Required Practical 8(b)?
To purify a Water Sample by Distillation
Objective - To separate pure clean water from a sample containing water and other substances
Hypothesis - A simple distillation apparatus can be set up to separate pure water from a mixture of water and unwanted substances
Method:
- Add the water sample to the conical flask and set up the apparatus for distillation as shown in the diagram
- Heat the water using the Bunsen burner until boiling occurs
- Reduce the heat so that the water boils gently for some time
- The distilled water will collect in the cooled test tube
- Collect about 2 cm depth of water in this way, then stop heating
- Analyse the water you have distilled by determining its boiling point
Evaluation:
The pH of the water can be tested as well as its boiling point
Conclusion:
Simple distillation can be used to produce pure water from a sample of impure or contaminated water
Where can waste water come from?
From domestic and agricultural sewers, animal farms and nutrient run-off collected from fields, etc
How is sewage treated?
- Screening & Grit removal
- Sedimentation
- Aerobic digestion
- Anaerobic digestion
What is screening and grit removal?
The first stage of treatment of sewage waste water
Involves the removal of large materials such as plastic bags or twigs
What is sedimentation?
Sedimentation is the second stage of treatment
It occurs in a SETTLEMENT TANK, where the water is allowed to stay still in the tank while heavier solids SINK to to the bottom
The lighter matter called EFFLUENT floats to the top
What is aerobic digestion?
Third stage of treatment of sewage waste water
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
What is anaerobic digestion?
The last stage of the treatment of sewage waste water
Breaks down the sludge from the BOTTOM of the settlement tank where SEDIMENTATION OCCURED
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, which is used as a source of energy and the leftover digested waste is used as a fertiliser
What happens when there are extra toxic substances in the water?
Additional phases of treatment, such as membranes or additional chemicals or UV radiation
Does desalination use more energy than cleaning sewage waste?
No, desalination involves more energy despite waste water treatment being a longer process
What are some biological processes of extracting metals from their ores?
BIOLEACHING and PHYTOMINING
What is Phytomining?
Some plants absorb metal through their roots, so these plants are grown in areas KNOWN to contain metals of interest in the soil.
As the plants grow, these metals are taken up through the plants’ vascular system and become concentrated in specific parts such as their shoots or leaves.
These parts of the plant are harvested, dried and burned
The resulting ash contains metal compounds from which the useful metals can be extracted by displacement reactions or electrolysis
What is bioleaching?
A technique that uses bacteria to extract metal from its ores.
Some strains of bacteria break down ores to form acidic solutions containing metal ions
This solution is called a LEACHATE which contains significant quantities of metal ions
These ions can then be REDUCED to the solid metal form and extracted by displacement reactions or electrolysis
It does NOT require high temperatures but it does produce TOXIC SUBSTANCES which need to be treated so they dont contaminate the environment.
Bioleaching is not only used for the primary extraction of metals but it is also used in mining waste clean up operations
What is the life cycle assessment?
An analysis of the overall environmental impact that a product may have throughout its lifetime
Broken down into 4 main stages - Raw materials, manufacture, usage and disposal
How does obtaining raw materials harm the environment (LCA)?
Using up limited resources such as ores and crude oil
Damaging habitats through deforestation or mining
How does manufacturing have an impact on the environment (LCA)?
Using land for factories
Fossil fuel machines emitting harmful gases
How does the usage of a product harm the environment (LCA)?
(depending on the product) A car could impact the environment massively through erosion of land and emissions f harmful gases whereas a table wouldn’t do much harm at all
How does the disposal of a product have an impact on the environment (LCA)?
It could use up space at landfill sites
It could be littered and destroy habitats if not biodegradable
May not be recyclable
LCA of a plastic bag
Raw materials - Crude oil, finite resource, lots of energy to process
Manufacture - Fractional distillation, cracking, polymerisation, not much waste, cheap to manufacture
Usage - Reusable
Disposal - Can be recycled, often littered, not biodegradable, takes up space in landfill
LCA of paper bag
Raw materials - From trees, deforestation
Manufacture - Pulping requires lots of energy, lots of waste products
Usage - Not reusable (mostly)
Disposal - Biodegradable, can be recycled, non-toxic
How can we maximise efficiency of products after use?
Reuse and recycle after use
Advantages of recycling
- Economically beneficial to recycle some metals such as ALUMINIUM
- Becoming a major industry and provides employment
- Raw materials are being used up and soon there will be very little in the future so recycling is crucial for sustainable development
Is it better to mine or recycle metals?
Mining and extracting metals from their ores has detrimental effects of the environment and ecosystems.
So it is much more energy efficient to recycle metals than it is to extract them (melting and remoulding is less expensive)
Disadvantages of recycling
- Collection of the materials via transport requires energy and fuel
- Materials need to be sorted before recycling which requires labour and energy
What is degradation of metals?
When metals react with substances when exposed to the environment for prolonged periods of time, called CORROSION on the SURFACE of the metal ONLY
What must be present for rusting to occur?
Oxygen and water must be present for rusting to occur
What is rusting?
A chemical reaction between iron, water and oxygen to form the compound Iron (III) Oxide
It occurs faster in SALTY WATERS since the presence of NaCl catalyses the process
Why is rusting bad for industry?
Rust weakens metals because it flakes off the surface of iron easily which exposes the underneath iron to rust, etc, causing chain reactions whereby the structure becomes weaker
What happens when aluminium reacts with oxygen?
Produces Al2O3, which forms a tough protective layer covering the aluminium, preventing further corrosion
What does a nail rust the best in (practical)?
Air and water, because they are both required for rusting to occur
What are some rusting prevention methods?
Galvanising and Sacrificial protection
What is galvanising?
A process where the iron is coated with a layer of zinc.
ZnCO3 is formed when zinc reacts with oxygen and CO2, which protects the iron by the barrier method
Zinc loses electrons more easily, so the iron stays protected as it accepts the electrons released by zinc, remaining in the reduced state and this it does not undergo oxidation
What is sacrificial corrosion?
When a more reactive metal is intentionally allowed to corrode to protect the less reactive metal underneath
What are alloys?
Mixtures of metals (or non-metals) where the metals are not chemically combined, and have often different properties such as more strength, hardness or resilience to corrosion or extreme temperatures, etc.
They contain atoms of different size which distort the regular layered arrangements of atoms making it more difficult for the layers to slide over each other so are much harder and stronger than the original metal
What is an aluminium alloy?
Where aluminium is mixed with copper, manganese and silicon for stronger and lighter properties, as well as being more corrosion resilient
What is a gold alloy?
Gold alloys are made to make jewellery, and their pureness is expressed in carats, eg. 24 carat is pure, but 12 carat is 50% pure, etc
What are steel alloys?
Iron from a blast furnace (cast iron) is too brittle, so most if it is converted to steel by REMOVING SOME OF THE IMPURITIES.
It can be used in construction, transport, manufacturing and other industries
What are ceramics?
Materials that are neither organic or metallic
What are properties glass ceramics?
- Transparent
- Strong
- Glass insulates against heat
- Transparent so idea for windows
- Very durable
What are clay ceramics?
Hardened materials that resist compressive forces, and can be used in bricks which can withstand massive weight and pressure
Properties and uses of polymers industry
Poor conductors of heat and electricity so are very good insulators
Extremely useful for insulating electrical wiring and prevent electric shocks and overheating
What is LDPE?
Low density Polyethene can be made at high pressures and moderate temperatures which is used for bags and bottles for flexibility purposes
What is HDPE?
High density Polyethene is produced at lower temperatures and pressures and with the use of a catalyst.
The polymer has a more rigid solid structure and is used to produce water tanks, mouldings and drain pipes
What are Thermosoftening polymers?
Consist of individual chains entwined with each other with weak intermolecular forces holding the polymer chains together.
Low melting points and can be MELTED AND REMOULDED to form different shapes
What are thermosetting polymers?
Strong cross-links between monomers on different chains so hold the structure together, hence the structure is strong and rigid so don’t soften under heating
What are composites?
Materials made from two components, REINFORCEMENTS and a MATRIX
The reinforcement material is EMBEDDED in the matric material which acts as a BINDER
The properties depend on the reinforcement and matric so it can be tailor engineered to meet specific needs
What are some common examples of composites?
Fibreglass and steel reinforced concrete
What is a natural composite?
Wood. Consists of cellulose fibres held together by an organic polymer mix
Properties and uses of carbon fibre?
- Extremely strong
- Lightweight
Used in aviation, aeronautics and racing bikes
Properties and uses of steel reinforced concrete?
- Immense tensile and compress
