Resources Flashcards
Sustainable / renewable resources
Meets the needs of current generations without compromising the ability of future generations to meet their own needs
What is potable water?
Water which is safe for human consumption, and which has sufficiently low levels of dissolved salts and microbes and a pH between 7.5 and 8.5
How is most potable water in the UK produced?
- Choosing source
- Passing through filter beds
- Sterilisation
How is water made potable? (detailed)
- Filter out big things (eg. Sticks) with a wire mesh
- Use sand beds and gravel to filter out finer particles
- Sterilise it (through bubbling chlorine through it, exposing it to UV light or exposing it to ozone)
Benefits and negatives of surface water
- Easy to access
- Replenished frequently
- Can dry up in sun
Desalination
- Used to extract potable water from sea-water
- Unlimited because it is from the sea
- However requires huge amounts of energy, lots of energy
- Distillation involves simple distillation but larger quantities
- Collect water vapour and condense it to produce potable water
- Reverse osmosis involves salty water being passed through a membrane
- Only allows water molecules to pass through, so all the larger ions and molecules are trapped, leaving pure and distilled water behind for drinking because it is POTABLE
How to treat sewage water?
- Screening and Grit removal
- Sedimentation to produce sewage sludge and effluent
- Anaerobic Digestion of sewage sludge
- Aerobic digestion of effluent (biological treatment)
COpper
Copper stores are running out, so we have to extract copper from low-grade ores
Phytomining, bioleaching
They avoid mining, digging and moving or disposing of large rock
What is Phytomining?
Phytomining uses plants to absorb metal compounds through their routes
The plants are then harvested and burned to produce ash containing the metal compounds
High concentration of metal ion in tissue, thus also in the ash
Bioleaching
Uses bacteria to produce LEACHATE solutions that contain metal compounds
Bacteria is mixed with the low-grade ore
Bacteria carries out a chemical reaction
How is copper etractedf?
After bioleaching or phytomining, the leachate/ product needs to have the metal extracted from it
Copper can be displaced from the ore using iron
Iron is more reactive than copper so can be displaced
Scrap ion is used because it is cheap
Copper can also be extracted by electrolysis
Key points about bioleaching and phytomining
Both of these allow us to economically extract metals from low-grade ores
They do not require digging or transporting of rock
What is the Haber process
The production of AMMONIA
Which can be used for FARMING
Equation of Haber Process
N2 + 3H2 2NH3
Sources of hydrogen and Nitrogen?
- Hydrogen from the AIR
- Nitrogen from reacting METHANE with STEAM
How does the haber process work?
Passing purified Hydrogen and Nitrogen over an IRON CATALYST at around 450 degrees celsius and 200 atmospheres pressure
Hydrogen and Nitrogen reacts to form ammonia.
Reversible reaction, so some of the ammonia cools down and breaks back into nitrogen and hydrogen
To increase the yield, the ammonia is cooled and turned into a liquid when it is
removed
Unreacted nitrogen and hydrogen is recycled back over the iron catalyst
Temperature and pressure is optimal for the shifting of the equilibrium and economic cost when making the yield of ammonia as great as possible.
Low temp increases yield because it is exothermic, but low temperatures slow rate of reaction so it is COMPROMISED at 450 degrees celsius.
IRON CATALYST INCREASES THE RATE OF REACTION
High pressure shifts equilibrium to the products side, increasing its yield, but high pressure is costly and dangerous to work with high pressures. So is temperature.
NPK fertilisers
Nitrogen
Potassium
Phosphorus
Improve agricultural productivity (larger plants and faster growing)
NPK fertilisers are formulations of different salts
These salts contain the required elements in the percentages needed by the plants
Compounds in NPK Fertilisers and their production
We use AMMONIA and react it with NITRIC ACID to form AMMONIUM NITRATE which is the main compound in NPK fertilisers
Potassium in NPK fertilisers comes from salts potassium chloride or potassium sulphate. BOTH MINED DIRECTLY FROM THE GROUND AND DO NOT NEED FURTHER PROCESSING.
Phosphate rock has to be chemically processes before being used in fertilisers
Treating Phosphorus with Nitric Acid
Treating Phosphate rock with NITRIC ACID produces PHOSPHORIC ACID and CALCIUM NITRATE
Phosphoric acid contains phosphorus but we cannot use this directly on plants, so it is NEUTRALISED with AMMONIA
Then Ammonium Phosphate is used in NPK fertilisers
Treating Phosphorus with Sulphuric Acid
- Mixture of calcium Phosphate and calcium Sulphate
- This is called SINGLESUPERPHOSPHATE and can be used in NPK fertilisers
Treating Phosphorus with phosphoric Acid
- Forms Triple superphosphate
- Which can be used in NPK fertilisers
In a school Lab or Industry we produce ammonium nitrate by…
School Lab
- Using dilute solutions of ammonia and nitric acid
- This is to make them safe to work with
- Crystals produced using a water bath and a bunsen burner, requiring a lot of heat energy
- Batch process, not much produced per time
Industry
- Ammonia is used as a gas
- Nitric acid is concentrated
- much more dangerous as the reaction is very exothermic an the heat has to be safely removed and used in later stages
- This heat can be used for evaporation
- Chemicals are produced by a continuous process, so more can be produced more easily
