Unit: 2 - fertilizers

Question 1

What is the food plants require(not photosynthesis)?

Answer 1

there are three key elements which provide the nutrients required for plant growth: nitrogen, phosphorus and potassium;

growing plants require nutrients, including compounds containing nitrogen, phosphorus or potassium;

fertilisers are substances which restore elements, essential for healthy plant growth, to the soil;

the percentage composition of an element in the fertiliser can be calculated - they are usually shown as percentage amounts on the side of fertiliser packaging.

Question 2

What is a fertilizer?

Answer 2

ammonia and nitric acid are important compounds used to produce soluble, nitrogen-containing salts that can be used as fertilisers;

ammonia is a pungent, clear, colourless gas which dissolves in water to produce an alkaline solution;

ammonia solutions react with acids to form soluble salts:
ammonia solution + an acid → an ammonium salt + water

Question 3

What is the haber process?

Answer 3

the Haber process is used to produce the ammonia required for fertiliser production:
N2(g) + 3H2(g) ⇌ 2NH3(g)

at low temperatures, the forward reaction is too slow to be economical;

if the temperature is increased, the rate of reaction increases but, as the temperature increases, the reverse reaction becomes more dominant;

an iron catalyst is used to increase reaction rate;

ammonia is the starting material for the commercial production of nitric acid.

Question 4

What is the ostwald process?

Answer 4

the Ostwald process uses ammonia, oxygen and water to produce nitric acid;

platinum catalyst is used in this process