C10: Using Resources Flashcards
(64 cards)
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