CHEMICAL SYSTEMS: FERTILISERS Flashcards
Non-mineral nutrients in plants
C, H and O Obtained from the atmosphere (CO2) and rain (H2O)
Primary nutrients for plants
Nitrogen (N), phosphorous (P) and potassium (K) Function:
N: essential for plant growth, green leaves
P: development of roots, stems and seeds
K: resistance against diseases and production of flowers/fruits
NPK fertilisers
Fertilisers containing the three primary nutrients for plants. They contain ammonium nitrate (NH4NO3), ammonium phosphate [(NH4)3PO4] and potassium chloride (KCℓ).
N : P : K ratio
The percentage nitrogen, phosphorous and potassium in a fertiliser.
Fractional distillation of liquid air
Industrial preparation of nitrogen from air.
Steam reforming
Preparation of hydrogen from earth gas (methane) Reaction: CH4 + H2O → 3H2 + CO
Haber process
Industrial preparation of ammonia Reaction:
N2 + 3H2 ⇌ 2NH3 Iron catalyst
Ostwald process
Industrial preparation of nitric acid Reactions:
Catalytic oxidation of ammonia; catalyst:
Pt 4NH3 + 5O2 ⇌ 4NO + 6H2O
2NO + O2 → 2NO2
3NO2 + H2O → 2HNO3 + NO
OR
4NO2 + 2H2O + O2 → 4HNO3
Contact process
Industrial preparation of sulphuric acid Reactions:
S + O2 → SO2
2SO2 + O2 → 2SO3
Contact catalyst: vanadium pentoxide (V2O5) SO3 + H2SO4 → H2S2O7 (H2S2O7:
fuming sulphuric acid
OR pyro sulphuric acid
OR oleum) H2S2O7 + H2O → 2H2SO4
Preparation of ammonium sulphate
ammonia + sulphuric acid → ammonium sulphate
2NH3 + H2SO4 → (NH4)2SO4
Preparation of ammonium nitrate
ammonia + nitric acid → ammonium nitrate
NH3 + HNO3 → NH4NO3
Eutrophication
The process by which an ecosystem, e.g. a river or dam, becomes enriched with inorganic plant nutrients, especially phosphorus and nitrogen, resulting in excessive plant growth. As plant growth becomes excessive, the amount of dead and decaying plant material increases rapidly
