C10: Using Resources Flashcards
What minerals do plants need and why? (3)
N: Encourages leaf growth and stem formation
K: promotes flower and fruit production and disease resistance
P: (phosphorus) seed growth and root development
What are NPK fertilisers?
A fertiliser than contains correct proportions of nitrogen, potassium and phosphorus for plant growth
What is an advantage of NPK fertilisers compared to others?
They are designed with correct proportions for better yield unlike seaweed, manure or other natural fertilisers
Which water soluble ions do fertiliser compounds contain? Why are they water soluble?
Nh4+
NO3-
PO4 3-
So they can be absorbed by plants
Describe the haber process
1: nitrogen from the air and hydrogen from natural gas is pumped through compressor pipes
2: the gases are compressed to 2000 atmospheres inside the compressor
3: the pressurised gasses are pumped into a tank with catylic iron beds at temps 450.C
4: the ammonia is cooled and liquified and removed
5: the untested N2 and H2 is recycled
What is the reversible equation for ammonia production (The haber process)
N2(g) + 3H2(g) - 2NH3(g)
What are some uses of ammonia?
Fertilisers
Textiles
Explosives
Haber process: What happens to the equilibrium and yield/rate when you increase temperatures?
Rate = increase
Equilibrium = shift left
Haber process: What happens to the equilibrium and yield/rate when you decrease temperatures?
Rate= decrease
Equilibrium = shifts right
Haber process: What happens to the equilibrium and yield/rate when you increase pressure?
Rate = increase
Equilibrium = shift’s right
Haber process: What happens to the equilibrium and yield/rate when you decrease pressure?
Rate = decrease
Equilibrium = left
Haber process: What happens to the equilibrium and yield/rate when you add a catalyst?
Rate = increase
Equilibrium = no shift
Why is the temperature 450.C for the haber process?
A higher temperatures means the the reverse reaction is favoured so a higher yield of reactants
At a low temp, a higher yield of products would be made
But at lower temperatures the reaction is too slow , so 450 is a compromise
Why is the pressure at 200 atmospheres for the haber process?
A lower pressure would favour the reverse reaction as it will attempt to counteract the change by creating more molecules , so a high yield of reactants
A high pressure would favour the forwards reaction as it willl try to decrease the pressure by creating fewer molecules, so a higher yield of products
But, high pressures can be dangerous and expensive equipment is needed
So 200 atm is a compromise
Why is a catalyst used in the haber process?
It doesn’t affect the equilibrium, but it increases the rate as the activation energy is lowered
It doesn’t effect yield either
It decreases costs
What is a finite resource?
A resource that will eventually run out because the rate of production is lower than the rate of use
What are examples of renewable resources
Timber, solar power, leather, cotton
What are examples of non renewable resources?
Minerals from crust, ethanol, coal , oil
What is potable water?
Safe for human consumption
Is potable water pure?
No
Sources of potable water?
Surface water (lakes, rivers, reservoirs
Aquifers (porous rocks underground) - groundwater
2 ways to treat water?
1) filtration to remove debris then sterilising (with Uv light , ozone or chlorine) to remove microbes and bacteria
2)desalination -removal of salt from sea water through distillation or reverse osmosis when the water is put through a semi permeable membrane to filter the salt
What is a negative about desalination?
Large amounts of energy and expensive
RP8: analysis and purification of water samples
1) use universal indicator on different water samples to determine the pH
2) weiagh an empty basin to 2 decimal places
3) add 25 cm3 of the first water sample into the basin
4) heat the basin until majority of the water is evaporated
5) weigh the basin once cooled and calculate the mass of the dissolved solids
RP8 b : purifying a water sample by distillation
1) add water sample to a conical flask and set up the distillation apparatus
2) heat the water
3) collect the distilled water
5) determine bp
Sources of waste water
Sewage, agricultural waste
What is the process at sewage treatment plans?
1) screening and grit removal (remove twigs and bags etc.)
2) sedimentation - water is set still in a settlement tank and sewage sludge sinks whilst effluent floats
3) aerobic digestion - effluent is removed and treated by aerobic digestion (air is pumped into the water to encourages the breakdown of microbes
4) anaerobic digestion- the sewage sludge is broken down through anaerobic digestion. This releases methane gas which can be used for energy
Sometimes toxic substances may be removed through chemicals and UV
Alternative methods of extracting rose (phytomining)
1) plants are grown in soil with metals of interest
2) as the plants grow, the metals get absorbed through the plants vascular system and become concentrated is its leaves and shoots
4) these parts of the plant are harvested, dried and burned
5) this ash contains metal compinds which can be extracted through displacement or electrolysis
Alternative methods of extracting ores (bio leaching)
1)some bacteria can break down ores to form acidic solutions contains metal ions
2) this solution is called a leachate which is rich in étal ions
4) these ions can be reduced to metal by displacement or electrolysis
What is a LCA
Life cycle assessment: an analysis of the overall environmental impact that a product has had over its lifetime
Stages of an LCA?
RAW MATERIALS: obtaining the materials can use up resources and damage habitats and emit gases
MANUFACTURING: this stage can use up land for factories ,produce waste or use fossil fuels
USE: this stage can cause air pollution (cars)
DISPOSAL: this stage can use up space at landfill sites and can be recycled
What is sustainability?
Meeting the needs of the current generation without damaging the lives of future generations
What is corrosion?
The destruction of materials by chemical substances in the environment which react
What is the formula for rusting?
Iron + water + oxygen - hydrated iron (III)oxide
Is an iron nail in a test tube is exposed to water and air, will it rust?
Yes, it is exposed to oxygen and water
If in iron nail in a test tube is filled with water with oil on top, will it rust?
No, te oil provides a barrier to prevent oxygen diffusing into the water
If a nail in a test tube ie exposed to air and has calcium chloride below it, will it rust?
No, the calcium chloride absorbs all water molecules
If an iron nail is covered in aliminium, will it rust?
No the aluminium oxide acts as a protective layer
What are prevention methods for rusting?
Barrier- paint, oil, grease, electroplating
Sacrificial protection- a more reactive metal can be attached to a less reactive one so it oxidises instead e.g. zinc on steel ships
What is galvanising?
When iron is protected with a layer of zinc as a sacrificial layer
Why are alloys harder?
The different sized atoms distorts the layers
What is bronze made of?
Copper and tin
Properties and uses of bronze
Tough, corrosion resistant
Used to make medals and statues
What is brass made of?
Copper and zinc
Uses and properties of brass
Complex shapes, corrosion resistant
Ornaments, instruments
Gold alloys
24 carat- pure gold, soft, expensive
12 carat- alloy, cheaper
Steel alloys properties - high carbon
Strong and brittle
Steel alloys properties - low carbon
Softer , malleable
Stainless steel?
Iron nickel, cobalt
Corrosion resistant
Aluminium alloys - high density
String
Aluminium alloys - low density
Light
What is steel made of?
Iron and carbon
What are ceramics?
Non metal solids with high melting points
In what conditions is low density poly(ethene) made?
High pressure and moderate temperatures
Properties of low density poly(ethene)
Flexible
In what conditions is high density poly(ethene) made?
Low temperatures and pressures with a catalyst
Properties of high density poly(ethene)
Rigid, solid
What is a thermosetting polymer?
Consists of strong cross linked chains with string rigid structures and high melting points, used in plugs
What is a thermosoftening polymer?
Tangles chains with no cross links, low melting points, can be melted and moulded, used for packaging
What is concrete made of and what are its properties?
Sand /gravel and cement, strong
What is fibreglass made of and what are its properties?
Glass fibres, polymer resin, low density and strong
What is carbon fibre made of and what are its properties?
Carbon nanotubes and polymer resin, strong and light
What is wood made of?
Cellulose fibres and organic polymer
