Fertilisers Flashcards
What are the 3 things plants need to survive?
- Sun energy
-Co2
-Water
What is the photosynthesis equation?
water+co2—(light energy)——— sugar+oxygen
Why are fertilisers needed?
Fertilisers are needed to resupply the soil with the three elements plants need to be healthy
What are the three elements found in fertilisers
- Nitrogen
- Phosphorus
- Potassium
What happens when you add fertilisers to crop fields?
When you add fertilisers to crop fields it produces four times more food than a field without fertilisers. It also replaces the nutrients lost when harvesting
What are three examples of natural fertilisers
- Manure
- Slurry
- Compost
advantages and disadvantages of using natural fertilisers
advantages
- Less expensive
Disadvantages
- Released slowly over time
- Not as effective
- Risk spreading disease
- Smell
What is a synthetic fertiliser?
A synthetic fertiliser is a chemical compound that contains nitrogen, phosphorous and potassium which can be used as fertilisers.
Advantages and disadvantages of using a synthetic fertiliser
Advantages
- Quantity of chemicals are controlled
- Easier to spread evenly
Disadvantages
- More expensive
- Quickly washed of by rain
- Can go into lakes and cause extra growth of algae
- Can kill fish if exposed to them
What do fertilisers need to be in order to be fertilisers?
Fertilisers also have to be soluble
Why is nitrogen hard to break?
It takes a lot of energy to break apart a nitrogen molecule as nitrogen has triple bonds
How do you know how much of each chemical is in a fertiliser?
N;P;K 12;8;4
12%- nitrogen
8%- Phosphorus
4%- potassium
What is produced during the Haber process?
Ammonia is produced during the Haber process
(NH3) - 3:1 ratio
What kind of catalyst is used during the Haber process?
An Iron catalyst
What do they use to improve the efficency during the Haber process
They use unreacted nitrogen and hydrogen to improve the efficency of the Haber process
What is the ideal temperature and pressure range for the haber process
The ideal temperature and pressure range for the haber process is 380-450 (temperature) and 250 (pressure)
Why does the pressure being 250 help
The pressure being 250 helps the nitrogen and hydrogen to combine. If the pressure is any higher the cost of equipment is too expensive
Why does the temperature of 380-450 help
The temperature being 380-450 helps as if it was any higher it would break the ammonia
Ammonia as a fertiliser
Ammonia is an alkaline gas so cant be used as a fertiliser directly. It is very soluble forming ammonium hydroxide. However as it is still very alkaline it would damage plants so salts of ammonia are used. Devices like burettes are used to make sure the exact quantities are used.
what provides energy for the natural nitrogen in the haber process
Lightning
What i s the reactant in the haber process
hydrogen
How can this process be made more economical?
Use unreacted gases as a catalyst
