Using resources Flashcards
What are 4 examples we use the earths resources?
Warmth
Shelter
Food
Transport
How does chemistry plays an important role in how we use resources?
Artificial fertilisers allows us to grow more food with the land available.
Allows us to provide water which is safe to drink
PHTOMINING AND BIOLEACHING help us to extract metals more efficiently
What is potable water?
Water that is safe to drink
What is one key idea about potable water?
Potable water is not the same as pure water.
What does pure water contain and it PH?
NOTHING!
Not even dissolved solids such as salt.
PH 7 (it’s neutral)
What does potable water contain and it PH?
Often contains dissolved solids and PH may not be 7
What are the 2 parts of “Required practical 8: Water” ?
-To analyse a sample of water for purity
-To purify a sample of water by distillation
What is the process of “Required practical 8: Water (analyse a sample of water by purity) “?
- First we check the PH of the water. Pure water has a PH of 7. We an check this by placing small amounts of water onto a piece of universal indicator paper. If green the PH is 7
- If the PH is not 7 then the sample contains dissolved acid or alkali and therefore is not pure
- If the PH is 7 then the water still not may be pure. It may still contain dissolved solids so now we need to test for those.
- We now need to test for those dissolved solids by first balancing the weight of an empty evaporating basin. We need to record the mass
- We fill the evaporating basin with our water sample and place the basin on a tripod or gauze
- We know use a Bunsen burner until it has all evaporated
- We allow the evaporating basin to cool and weight it again. IF THE WATER SAMPLE CONTAINS ANY DISSOLVED SOLIDS THEN THE MASS OF THE EVAPORATING BASIN WILL HAVE INCREASED (Because the water will have evaporated but the dissolved solids will have formed crystals)
HOWEVER EVEN IF THE MASS OF THE BASIN DID NOT INCREASE THEN THE WATER MAY STILL NOT BE PURE. BECAUSE OF DISSOLVED GASES
How are these resources produced?
Agriculture
What is the process of “Required practical 8: Water (purify water by distillations) “?
- This is our apparatus. A comical flask containing our WS (Water sample) which is on a tripod or gauze above a Bunsen burner. On top of the conical flask is a delivery tube that is pointed into a test tube. The test tube is sitting in a beaker containing ice and water.
2.We gently heat the WS using the Bunsen burner (we want the WS to boil gently) At this point the water will evaporate and form water vapour (steam) that travels along the collecting tube into the COLD test tube to condense back to liquid water (distilled water)
What does distilled water contain and PH?
No dissolved solids
PH 7
TRUE OR FALSE.
Distilled water = pure water
TRUE
What does drinking water have to have to be able to be drunken?
-Low levels of dissolved salts like sodium chloride
-low levels of microbe such as bacteria
What doe scientists call water that is safe to drink?
Potable water.
How is rain water a potable water?
Contains low levels of dissolved substances
Where is rain water collected?
In the ground in aquifers
lakes
rivers
reservoirs
How do we produce potable water?
- Choose a good source of fresh water e.g river
- We pass water through filter beds that remove leaves and suspended particles
- The water is then sterilised to kill microbes. We use chloring to sterilise the potable water in the UK
HOWEVER IN SOME PARTS OF THE WORLD OZONE OR ULTRAVIOLET LIGHT IS USED
Why in many places is fresh water scarce?
Some countries, the only available water may be too salty to drink e.g sea water
Why is sea water not able to be drunken and how potable water be produced from it?
-High levels of dissolved minerals
DESALINATION
What does desalination do?
Desalination reduces the levels of dissolved minerals down to an acceptable level for potable water
What are the ways of carrying out desalination and what are the issues?
-Use distillation
- Reverse osmosis (pass water through membranes)
-BOTH PROCESSES REQUIRE VERY LARGE AMOUNTS OF ENERGY WHICH MAKES THEM EXPENSIVE
What are the ways water is used?
-Personal hygiene (baths & showers)
-Flushing toilets and washing clothes
-Agriculture
What does sewage and agricultural waste water require?
Sewage and agricultural waste water require removal of organic matter and harmful microbes.
What does industrial waste water may require?
Industrial waste water may require removal of organic matter and harmful chemicals.
What is the process of sewage treatment?
- screening and grit removal (Passes through mesh to remove solids and grit)
2.sedimentation to produce sewage sludge and effluent
3.anaerobic digestion of sewage sludge - aerobic biological treatment of effluent.
What happens to the sludge?
The sludge is taken away to be digested by anaerobic bacteria.
In the absence of oxygen these bacteria produce biogas which can be burned for electricity
At the end the digested bacteria is used as fertilisers for farming
What happens to the effluent?
The effluent contain large amounts of organic molecules and harmful microorganism.
Air is bubbled through the liquid effluent to allow aerobic bacteria to multiply
In the presence of oxygen the aerobic bacteria digests the organic molecules and harmful organisms
The liquid effluent is safely discharged into nearby rivers or the sea
How is water used by the industry?
To make paper or chemicals
What is the easiest way to produce potable water?
Use ground water from aquifers. Because it’s usually safe to drink once treated with chlorine
How can aquifers be polluted?
Polluted from fertilisers from farms.
Why is copper becoming scarce?
There is a very high demand of copper.
It’s used in electronic equipment like phones.
Why so we have to extract copper from low-grade ores?
Because copper ores are becoming scarce
What is bad from extracting copper from low-grade ores?
It harder to extract the copper economically from these ores.
What does the word “economical” mean?
means cost-effective
What is the process of phytomining?
- Plants are grown on land containing the metal compound that we want
- These plants absorb the metal compound and they concentrate it in their tissue
- The plants are then harvested and burned
- At the end, the ask contains a relatively high concentration of the metal compound
What is the process of bioleaching?
1.In bioleaching, bacteria is mixed with the low grade ore
2. The bacteria carries out chemical reactions and they produce a solution called a leachate
3. The leachate contains the metal compound that we want
At the end of phytomining and bioleaching how do we extract the metal from the compound?
- Electrolysis
- In the case of copper compounds we can displace the copper using iron. Iron is more reactive that copper. We usually use scrap iron which is cheap
What are the key points of phytomining and bioleaching?
-Allows us to economically extract metals from low-grade ores (important as the earth’s resources are limited)
-These methods don’t involve digging, transporting and disposing large amounts of rock unlike traditional mining
What does a life-cycle assessment attempt to do?
Attempts to put a number on the environmental impact of a product
Assess the environmental impact of extracting and processing raw materials.
- Polymers such as plastics are produced using crude oil. That oil needs to be extracted from the ground and then transported to oil refineries The hydrocarbons need to be separated then cracked. This requires a lot of energy that is produced by fossil fuels.
2.Extracting metals requires a lot of energy and produce toxic waste products
Assess the environmental impact of manufacturing and packaging?
All these stages require energy and release harmful waste products
Assess the environmental impact of use and operation during its lifetime?
A product may require a large amount of batteries which releases large amounts of toxic waste
Asses the environmental impact of disposal at the end of its useful life, including transport and distribution at each stage?
Many products contain harmful chemicals. These chemicals have to disposed carefully and that may require a lot of energy.
May require energy to transport those products for disposal e.g a landfill or recycle centre
Life cycle assessment of a plastic bag
Plastic bags are produced from crude oil which is non-renewable.
Extracting crude oil can be harmful to habitats e.g oil leak
It then needs to be chemically processed which requires a lot of energy that releases waste products
PLASTIC bags are strong and can be reused
At the end transported to recycling or landfills
Noy non-biodegradable so not easily broken down by microorganisms meaning they are a major form of litter
Life cycle assessment of a paper bag
Paper bags are produced from trees which is renewable because we can simply plant more.
Felling trees for wood is extremely destructive to habitats such as forests
It then needs to be chemically processed which requires a lot of energy that releases waste products
Making paper requires huge amounts of water
PAPER bags can easily tear which make them often used once
At the end transported to recycling or landfills. Paper bags are often heavier then plastic bags so this can take more energy to transport
Problems with “Life-Cycle Assessment”?
We can measure the use of water, energy and the production of waste products.
But we cant always be certain of how damaging these are to the environment. This means we have to estimate or value judgements of how damaging it is which may not be accurate.
Can also be biased to support claims by advertisers
How is quarrying bad for the environment?
Produces large amounts of dust and destroys habitats
How is mining bad for the environment?
Can release harmful chemicals into the environment
Why else may quarrying and mining may be bad for the environment?
They require energy which often comes from limited resources like fossil fuels
Why is recycling and reusing helpful?
Save limited resources and energy.
Reduce amount of waste we produce having less harmful effect on the environment.
How can glass bottles be reused?
Crushed or melted to make different glass products or simply reused.
How can plastic bottles be reused?
Recycled to make fleece jackets and carpets.
How can we recycle metal?
We melt then and recast them into different products
What can be a problem we recycling metal?
It requires the metals to be separated. But that depends on the properties of the final product.
For example, scrap steel can be added to iron from a blast furnace. Reducing the amount of iron we need to extract from the iron ore.
