10. Using resources (the haber process and NPK fertilisers) Flashcards
What is the Haber process used to do?
to manufacture ammonia
What is the equation of the reaction of the Haber process?
nitrogen + hydrogen —> ammonia
Is the Haber process an exothermic or endothermic reaction?
exothermic
Why is ammonia so important?
it is used in fertilisers
What metal acts as a catalyst for the Haber process?
iron
Where do we get the nitrogen required for the Haber process?
we take it from the air
Where do we get the hydrogen required for the Haber process?
we make it from hydrocarbons
What are the steps for the Haber process?
- The purified nitrogen and hydrogen are passed over a catalyst of iron at high temperatures (450 degrees celsius) and high pressure (200 atmospheres)
- Some of the nitrogen and hydrogen react to form ammonia
- The reaction is reversible so some of the ammonia produced breaks down into nitrogen and hydrogen
- On cooling, the ammonia liquifies and is removed. The remaining nitrogen and hydrogen is recycled
What is a fertiliser?
a substance that is applied to soil, in order to supply plants with nutrients
Compounds of what three elements do NPK fertilisers contain?
- nitrogen
- phosphorous
- potassium
What are NPK fertilisers?
Formulations of various salts containing appropriate percentages of the elements (nitrogen, phosphorus, potassium)
What is the main reason plants need nitrogen?
to make amino acids to produce proteins
How is phosphate rock treated to produce soluble salts that can be used as fertilisers?
with nitric acid or sulfuric acid
What can ammonia be used to manufacture?
ammonium salts and nitric acid
What is produced when phosphate rock is reacted with nitric acid?
phosphoric acid and calcium nitrate
