Importance of nitrogen in agriculture and the forms it can be taken up in
- Poor growth, yellow leaves w out
- nitrate ions OR ammonium ions
Importance of phosphorus
poor root growth, discoloured leaves
Importance of potassium
poor fruit growth, discoloured leaves
Haber process equation
Nitrogen + hydrogen ammonia (Nh3)
N2 + 3H2 2NH3
Conditions needed in Haber process
Compromises for most
- Exo (450)
- Pressure - 200 (fairly high)
- iron catalyst
- Gases leaving reaction vessel are COOLED so ammonia can be liquefied + removed and reactants can be recycled
Contact process - final product and raw mats
Produces sulfuric acid
- sulfur
- o2
- water
Contact process - STAGE 1
Sulfur burns in air –> sulfur dioxide
S + O2 –> SO2 (exo)
Contact process - Stage 2
Sulfur dioxide + Oxygen 2S03 (sulfur trioxide)
Stage 2 conditions
- Exo: 450 compromise as catalyst only works about 380
- Vanadium oxide catalyst
- 2 pa as equilibrium position already is far to the right
Why is stage 3 in the contact process split into 2 stages?
As one stage reacting sulfur trioxide + water is VERY exothermic and a hazardous acidic mist is released
Contact Process - Stage 3, part 1
Sulfur trioxide + sulfuric acid (previously made) –> oleum (H2S2O7)
Contact Process - Stage 3, part 2
Oleum + water –> sulfuric acid (larger vol made)
2 methods to make ethanol
- Fermentation of sugars
- Hydration of ethene
What does the fermentation of sugar method consist of?
glucose –> co2 + ethanol (in the presence of YEAST) = process of fermentation
- yeast cells = enzymes that catalyse this conversion
- 35 degrees (due to enzymes)
- normal pressure, can do in school lab lab
What does the hydration of ethene method consist of ?
ethene(obtained from crude oil) + steam ethanol - 300 temp - 60 pa - phosphoric acid catalyst (industrial only)
Hydration of ethene method positives + negatives
- non renewable materials
- high temp, high pressure = high energy requirements
= COSTLY
BUT
- high rate of reaction
- high percentage yield
- high purity as one product
Fermentation of sugars positives + negatives
- low purity of product (needs filtering + frac distill)
- low percentage yield
- low rate of reaction
BUT
- sustainable as made from plant sugars = low cost
- mod temp, normal pressure = low energy = cheap
