C6.2 Flashcards
Which elements are in NPK fertilizers?
Nitrogen, Phosphorus and Potassium.
In which form is nitrogen used for fertilizers?
Ammonium nitrate.
In which forms can potassium be used for fertilizers?
Potassium chloride salt or potassium sulfate salt.
In which forms is Phosphorus used for fertilizers?
Single superphosphate, Triple Superphosphate and ammonium phosphate.
How is ammonium phosphate produced for fertilizers?
Phosphoric rock is treated with nitric acid, which produces calcium nitrate and phosphoric acid.
Phosphoric acid is then neutralised with ammonia, producing ammonium phosphate.
How is single superphosphate produced for fertilizers?
Phosphoric rock is treated with sulfuric acid. This produces single superphosphate, a mixture of calcium sulfate and calcium phosphate.
How is triple superphosphate made for fertilizers?
Phosphoric rock is treated with Phosphoric acid. This makes triple superphosphate.
Give 3 differences between producing fertilizers in a lab an dproducing fertilizers in industries.
Using ammonium nitrate as an example:
1 - Lab is batch process. Industry is continuous.
2 - Lab uses dilute solutions of nitric acid and ammonia for safety reasons. Industry uses highly concentrated nitric acid and ammonia is gas form, resulting in a dangerous, high-exothermic reaction.
3 - Lab uses a lot of heat energy to form crystals using a water bath and a bunsen burner. Industry uses some of the heat energy released by the prior exothermic reaction for evaporation.
Theoretically, what are the ideal conditions for the Haber Process?
- Low temperatures to maximise the yield of ammonia.
- High pressures.
- High concentrations of nitrogen and hydrogen.
In reality, what are the ideal conditions for the Haber process?
- Temperature around 450°C. This is cool enough for the equilibrium to shift to the product’s side, but high enough for the reaction to happen quickly enough to be economical.
- Pressures of around 200 atmospheres. This is high enough for the equilibrium to shift to ammonia’s side, but low enough to be cheaper for the company and less hazardous for workers.
- An iron catalyst is used to speed up the reaction.
What does the Contact Process produce?
Sulfuric acid,H2SO4.
State the formula for stage one of the Contact Process.
Sulfur burns in air to make sulfur dioxide.
S + O2 —-> SO2
State the formula for Stage 2 of the Contact Process.
Sulfur dioxide and oxygen react together to make sulfur trioxide.
I CAN’T WRITE THE REVERSIBLE ARROW ON HERE PRETEND ITS A REVERSIBLE REACTION ARROW OKAY??!?!??!
SO2 + 3O2 —-><—- 2SO3
State the formula for stage 3 of the Contact Process.
Sulfur trioxide reacts with water to convert into sulfuric acid.
H2O + SO3 ——> H2SO4
Why are there two parts to stage 3 of the Contact Process?
The reaction for stage three, sulfur trioxide and water converting into sulfuric acid, is an extremely exothermic reaction that could produce an acidic mist. This is very dangerous.
What are the two parts to stage 3 of the Contact Process?
Part 1 - sulfur trioxide is passed 5hrough concentrated sulfuric acid to make a compound called oleum.
Part 2 - oleum is then added to water, which forms concentrated sulfuric acid.
What are the conditions for the stage 2 reversible reaction in the Contact Process?
- Low pressure of 2 atmospheres
- Low temperatur of 450°C
- A vanadium oxide catalyst.
