C10 - Using Resources Flashcards
What is potable water?
Water that is safe to drink.
What is not pure water?
Has dissolved salts and microbes but they are at low enough levels to drink.
Is not pure water potable?
Yes.
What are 3 sources of fresh water?
Ground water, lakes, rivers
What are 3 steps to make potable water from fresh water?
Choose appropriate source of fresh water.
Pass water through filter beams.
Sterilise water (kill microorganisms)
What are 3 methods to sterilise water?
Use chlorine, ozone or UV.
What is desalaination?
Removing salt from sea water.
How does reverse osmosis work?
Water put under high pressure.
Passed through a membrane.
Pores allow water molecules through but not most ions and molecules.
What are the disadvantages of reverse osmosis?
Expensive membranes.
Large volume of water waste - low efficiency.
How does distillation work?
Sea water heated until it boils.
Salt remains in the liquid and the steam is pure water.
What are the disadvantages of distillation?
Requires lots of energy to boil and condense the water.
The waste water is salty and can be difficult to dispose of without harming marine ecosystems.
What is the first step of treating sewage?
Screening - removing large solid particles.
What is the second step of treating sewage?
Sedimentation - solids sink to form sewage sludge, liquid remains above.
What is the liquid that remains above called?
Effluent.
What is the third step of treating sewage?
Sludge is dried and anaerobically digested (broken down by microorganisms)
What can the products of the third step of sewage treatment be used for?
Dried sludge used as fertiliser.
Digestion of sludge produces biogas which can be used for electricity.
What is the fourth step of treating sewage?
Effluent is aerobically digested in the presence of oxygen. This removes organic matter and harmful organisms.
What is a finite resource?
Can not be replaced once it has been used.
What is a renewable resource?
Can be replaced once it has been used.
What are the 4 main uses of the Earth’s resources?
Transport.
Food.
Heating.
Housing.
What is sustainable development?
Using resources to meet the needs of the present without compromising the needs of the future.
What are sustainable methods for dealing with metals?
Recycling them.
What are sustainable methods for fuel for transport?
Use biofuels.
What are sustainable methods for electricity generation?
Use renewable energy.
What are 3 environmental problems with mining metals?
Destruction of habitats.
Use of fossil fuels in extraction.
Scarring of landscape.
What are life cycle assessments?
They asses the total effect of a product on the environment in it’s lifetime.
What are the 4 points assessed in a life cycle assessment?
Extracting and processing raw material.
Manufacturing and packaging.
Use.
Disposal.
Why is HDPE more dense that LDPE?
Chains are straight in HDPE, meaning they can be more tightly packed into an area.
There are strong intermolecular forces between HDPE molecules.
What are thermosoftening polymers?
Melt when heated as they have weak intermolecular bonds between molecules. Can be easily remolded.
What are thermosetting polymers?
Don’t melt when heated as they have strong crosslinks between molecules.
Where does water get released after sewage treatment?
Back into environment (rivers)
What are 2 methods used to desalinate water?
distillation
reverse osmosis
What needs to be removed from sewage and agricultural waste?
Organic matter and harmful microbes.
What needs to be removed from industrial waste?
Organic matter and harmful chemicals.
What are the advantages of recycling?
Less acid rain (metal ore lasts longer)
Less mining - less energy used for extraction
What are the disadvantages of recycling?
Difficult to separate metals from appliances.
Collection problems/ transport problems
Cost of transport
What is bronze and it’s use?
Alloy of copper and tin. Used for statues and decorative objects.
What is brass and it’s use?
An alloy of copper and zinc. Used for water taps and door fitttings.
What is gold and it’s use?
An alloy of silver, copper and zinc (usually). Used as jewellery.
What density are aluminium-magnesium alloys, and what is it’s use?
Low density. Used in aerospace manufacturing.
What are 3 steel alloys?
High carbon steel, low carbon steel, stainless steel.
What are the characteristics of high carbon steel?
Strong but brittle.
What are the characteristics of low carbon steel?
Soft and malleable.
What are stainless steels?
Steels containing chromium and nickel. They are hard and resistant to erosion
How are the properties of polymers determined?
Depend on what monomers they are made from and the conditions under which they are made.
What is the difference between HDPE and LDPE?
Both produced from ethene but using different catalysts and reaction conditions.
What is HDPE and LDPE?
High density and low density polyethene.
How is soda-lime glass made?
Heating a mixture of sand, sodium carbonate and limestone
How is borosilicate glass made?
Made from sand and boron trioxide, melts at higher temperatures than soda-lime glass.
How are clay ceramics made?
Heating wet clay in a furnace.
What is an example of a composite?
Fibreglass - glass fibres bound together in a polymer, used for making storage tanks.
What are the conductivities of glass ceramics, clay ceramics, plastics and composites?
Low.
What are the melting points of glass ceramics, clay ceramics, metal alloys and composites?
High.
What is the conductivity of metal alloys?
Good.
What is the melting point of plastics?
Usually low.
What are the properties of glass ceramics?
Stiff and brittle.
What are the properties of clay ceramics?
Stiff and brittle.
What are the properties of metal alloys?
Quite malleable.
What are the properties of plastics?
Flexible.
What are the properties of composites?
Usually stiff and brittle.
How are plastics made?
Polymerisation of monomers.
How strong are composites?
Very strong.
How strong are plastics?
Good strength.
How strong are metal alloys?
Good strength.
How strong are clay cermaics?
Strong under compression.
How strong are glass ceramics?
Poor strength.
What are composites?
Composites are a mixture of two materials with the product having a combination of the properties of each material.
Why is borosilicate glass needed as well as soda-lime glass?
It has a high melting point so is used in lab equipment and cooking.
Where is high carbon steel used?
Cutting tools as it is strong.
Where is low carbon steel used?
Used to make screws as it is soft and easy to shape.
Where are stainless steels used?
Construction as it is hard and resists erosion.
Why does aluminium not corrode much?
A layer of aluminium oxide forms and prevents further corrosion
What is bioleaching?
Using bacteria to extract specific metals from their ores.
What is the leachate in bioleaching?
The solution we get when a liquid passes through an organism, that contain metal compunds.
What are the advantages of bioleaching?
Cheap
Environmentally-friendly
Can be used for low-grade ores, useful as high-grade ores have low availablility.
What is phytomining?
When plants absorb metal compounds through their roots from the soil, and then are burned.
What are the 4 steps of phytomining?
Plant absorbs metal compounds.
Plant burned to produce ash.
Acid is added to ash, producing a leachate.
Copper obtained from displacement reaction with iron or electrolysis.
What is a leachate in phytomining?
Solution containing dissolved metal compounds.
What are the advantages of phytomining?
Less air pollution.
Requires less energy.
Low grade copper ores can be used.
Reduces waste rock.
What are the disadvantages of phytominning?
Produce toxic chemicals.
Slow.
Electrolysis requires large amounts of energy.
What are 4 methods to extract a metal?
Electrolysis.
Reduction with carbon.
Bioleaching.
Phytomining.
What are 4 methods used to prevent corrosion or rust?
Galvanising
Painting
Grease
Electroplating
What is the word equation for rusting?
Iron + oxygen + hydrogen -> Rust
What is rusting?
The corrosion of iron, which reacts with oxygen and water to form flaky iron oxide.
What is patina?
A thin layer of green on the surface of copper.
What is corrosion?
A metal breaking down by reacting with oxygen.
What is tarnishing?
To gather a thin layer of discolouration by reacting with the air.
What is a metal oxide?
A compound containing only a metal and oxygen.
What is galvanising?
More reactive metal on surface to protect.
What is electroplating?
Less reactive metal on surface to protect.
What do new methods of mining avoid in terms of the disadvantages of traditional mining?
Avoids producing as much CO2 and SO4.
Avoids digging, moving and disposing of large amounts of rock.
How is ammonia manufactured?
Haber process.
What type of reaction is the haber process?
A reversible reaction with an equillibrium.
Where is ammonia used?
It is an important industrial product used to make fertilisers.
What is the symbol equation for the haber process?
N2(g) + 3H2(g) ⇌ 2NH3(g)
What are fertilisers?
Fertilisers are formulations which may contain nitrogen, phosphorus and potassium compounds to promote plant growth.
What are NPK fertilisers?
Fertilisers that provide all three elements (nitrogen, phosporus, potassium)
What is the word equation for the haber process?
Nitrogen + hydrogen ⇌ ammonia
What are the common forms of nitrogen?
Ammonium salts NH4+
Ammonia NH3
Nitric acid HNO3
What is nitrogen needed for?
Leaf growth
Green colour
What is the common form of phosporus?
Phosphate rock (phosphorus oxides P205)
What is phosphorus needed for?
New roots.
Makes seeds.
Fruits and flowers.
What are the common forms of potassium?
Potassium chloride (KCl)
Potassium sulfate. (K2SO4)
What is potassium needed for?
Strong stems.
Growth rate.
How can you produce NPK fertilisers?
Reacting ammonia with nitric, sulfuric or phosphoric acid.
What are the 3 types of ammonium salts?
Ammonium nitrate, ammonium sulfate, ammonium phosphate.
What is the word equation for the production of ammonium slats?
Ammonia + acid -> ammonium salts
How is phosphate rock utilised in the production of fertilisers?
Reaction with nitric, sulfuric and phosphuric.
What are the products of phosphate rock with nitric acid?
Phosphoric acid + calcium nitrate.
What are the products of phosphate rock with sulfuric acid?
Mixture of calcium phosphate and calcium sulfate.
What is the product of phosphate rock with phosphuric acid?
Calcium phosphate.
Why is a compromise needed in the temperature conditions of the Haber process?
Low temp - rate is slow, but yield is maximised.
High temp - rate is fast, yield is low, heating is expensive.
What is the comprimise for temperature conditions in the Haber process between?
Comprimise between rate, cost and yield.
What is the comprimise for temperature conditions in the Haber process?
450 degrees celcius - rate is fast enough, yield is not maximised but still okay.
Why is a compromise needed in the pressure conditions of the Haber process?
Low pressure - rate is slow, yeild is not maximised
High pressure - rate is fast, yeild is maximised but is expensive.
What is the comprimsie of the pressure conditions of the Haber process between?
Yield, rate and cost.
What is the comprimise of the pressure conditions for the Haber process?
200 atm. - cost reduced, yeild not maximised but still okay.
What is the energy change of the forward reaction of the Haber process?
Exothermic - why decreasing pressure will cause a higher yield.
Where are the highest number of mols in the Haber process the reactants or the products?
Reactants - why increasing pressure will cause a higher yield.
List 3 conditions for the Haber process.
450 degrees celcius
200 atmospheres pressure
Iron catalyst.
Where do the reactants for the Haber process come from?
Nitrogen - from the air
Hydrogen - from natural gas
How is ammonia removed from the reaction mixture?
By cooling, this liquefies the ammonia gas.
What happens to unreacted gases in the Haber process?
Recycled.
What property must fertilisers have?
Soluble in water so they can be absorbed by plants.
How is ethanol produced from a sugar solution?
Fermentation.
Anaerobically digested.
30 degrees.
Add yeast
What is the appropriate temperature and pressure used in the reactor in the Haber process?
450 degrees celcius.
200 atm.
What type of metals are found found in catalytic converters?
Transition metals.
Write a word equation for haber process.
Nitrogen + hydrogen -> Ammonia
Write a symbol equation for haber process.
N2+3H2 ⇌ 2NH3
Where does nitrogen come from in the haber process?
The air
Where does hydogen come from in the haber process?
Natural gas
Why is ammonia important?
For making fertilisers
How is ammonia removed from the reaction mixture?
Cooling - liquefies ammonia.
