Topic 10 - Using resources Flashcards
(89 cards)
What does NPK stand for in NPK fertilisers?
N - Nitrogen
P - Phosphorous
K - Potassium
In what form can plants absorb nutrients?
Plants can only absorb nutrients as ions that are water soluble.
What is the formula for the reaction to form ammonium nitrate?
NH3 + HNO3 –> NH4NO3
Ammonia + Nitric acid –> Ammonium nitrate
What substance is ammonium nitrate?
A salt
How is ammonium nitrate made in the lab?
- ammonia solution in low concentration is titrated with nitric acid and then undergoes crystalisation. It is a low concentration as it releases less heat.
How is ammonium nitrate made in industry?
Ammonia gas is directly added to the reaction vates containing high concentration nitric acid.
How is potassium for NPK fertilisers obtained?
It is mined from sylvite deposits and potassium sulfate
How is phosphorous obtained for NPK fertilisers?
Rock is mined which is then reacted with acids to form salts.
How do different rock reactions produce phosphorous?
- with nitric acitd produces phosphoric acid and calcium nitrate
- with sulfuric acid produces calcium sulfate and calcium phosphate
- reaction with phosphoric acid produces produuces calcium phosphate(this one is known as triple superphosphate)
What are the advantages of NPK fertilisers?
Contains the right mix of nutrients.
What is the equation for the Haber process?
3H2 + N2 <–> 2NH3
Is the forward of reverse reaction of the Haber process exothermic?
Forward is exothermic, backwards is endothermic
What are the best conditions for the Haber process?
- Lower temperature(450°C)
- High pressure - 200ATM
- Catalyst - iron
- More reactant
What does the N2 and 3H2 come from in the Haber process?
N2 from the atmosphere and 3H2 from reacting methane with steam
What is the equation for obtaining 3H2 from methane and steam?
CH4 + 2H2O —> 3H2 + CO2
How is ammonia removed in the Haber process?
The ammonia is removed by condensing it into a liquid
What is the reason for the temperature in the Haber process?
450°C is used as it is a compromise between rate and yield - a higher temp increases the rate but reduces the yield
What is the reason for the high pressure in the Haber process?
200Atm is used as it favours the forward reaction, it is expensive to maintain however.
Why is a catalyst used in the Haber process?
Iron is used as a catalyst to speed up the reaction, save energy and increase yield.
How is waste water treated?
- Screening - removes any large material
- Sedimentation - separates out a liquid effluent at the top, and a sewage sludge at the bottom.
- The effluent undergoes aerobic digestion to be released into the environment
- The sludge undergoes anaerobic respiration
What can we turn sludge into and how?
- Fertiliser by making it undergo anaerobic digestion
- Methane to be burned after anaerobic respiration
How can water be made potable outside the UK?
- Reverse osmosis
2.Desalination
What is reverse osmosis?
- Forcing water through a PPM
2.The PPM blocks all the ions and larger molecules , separating it from water.
3.Freshwater is not needed for this
How does desalination work?
1.Water sample heated
2.water evaporates at it’s boiling point
3.Cools and condenses as it passes through a condenser
4. Impurities are left in the flask
5. Pure water will be left in the beaker
6. Test water with flame to check purity