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