nitrogen and fertilisers Flashcards
1
Q
what do plants require
A
nitrogen, phosphorus, potassium
2
Q
nitrogen fertiliser properties
A
- needed to make amino acids which are then needed to make proteins. This promote healthy leaves
- ammonium ions, NH4+ and nitrate ions, NO-3, are sources of soluble nitrogen
3
Q
phosphorus fertiliser properties
A
- promotes healthy roots
- phosphate ions, PO4 3- are a source of soluble phosphorus
4
Q
potassium fertiliser properties
A
- promotes growth and healthy fruits and flowers
- most common potassium compounds dissolve in water to produce potassium ions K+
5
Q
how is ammonia displaced
A
ammonia can be displaced from its salts by the addition of an alkali substance or adding a base
6
Q
what is the haber process
A
manufacture of ammonia
7
Q
haber process reaction
A
N2 + 3H2 <=> 2NH3
8
Q
describe haber process
A
- forward reaction exothermic
- temperature of about 450 degrees celsius: Lower temperature would favour yield but the rate of reaction would be to slow. Thus, at 450 deg celc, the rate and yield is economic
- pressure of about 200atm: higher temperature would favour yield and rate but its dangerous and expensive to maintain such a high pressure system
- catalyst is iron
9
Q
sources of hydrogen
A
- cracking of alkanes
- steam reforming of methane
- electrolysis of water
10
Q
sources of nitrogen
A
fractional distillation of air
