10b. Using Resources Flashcards
(61 cards)
What is the reaction for the Haber process?
Nitrogen + hydrogen = ammonia
N2 + 3H2 = NH3
What are the stages of the Haber process?
- Nitrogen (extracted from the air) and hydrogen (obtained from natural gas) are pumped through pipes as gases.
- The pressure of the mixture of gases is increased to 200 atmospheres (the gases are compressed).
- These pressurised gases are then heated to 450°C and passed through a tank which contains layers of catalytic iron beds. This is where some of the hydrogen and nitrogen react to form ammonia.
- The reaction mixture is the cooled so that ammonia liquefies and can be removed.
- Unreacted nitrogen and hydrogen are recycled.
What is ammonia?
Ammonia is a colourless, poisonous gas composed of one Nitrogen atom and three Hydrogen atoms all covalently bonded together.
When was ammonia discovered?
Ammonia was first produced in 1807 by scientist Humphry Davy.He electrolysed distilled water in the air and detected small amounts of ammonia as a result.
What is ammonia used for?
- The manufacture of fertilisers (it is converted into nitric acid to allow protein to be formed)
- The manufacture of explosives (it is converted into nitric acid)
- An ingredient in cleaning fluids
- Used in textiles
Why is it important to recycle unreacted gases?
Most hydrogen and nitrogen which go into the reactor leave unreacted, so by recycling them, they can reduce the cost of making reactants from raw material when they go back into the reactor. Rather than losing the gases, they can make more products from it which is money and energy saving.
Is the Haber process sustainable?
The Haber process is mostly not sustainable, as the production of ammonia is reliant on fossil fuels to provide energy. Burning fossil fuels creates a large volume of energy needed for the Haber process, however it is responsible for “1% of worldwide human carbon dioxide emissions”.
The Haber process heavily contributes to climate change, and is therefore not sustainable.
What are fertilisers?
Fertilisers provide mineral ions that are needed for healthy growth in plants
What does NPK stand for?
Nitrogen, phosphorus and potassium. These are substances that promote plant growth.
Why must fertiliser compounds be soluble in water?
So they can be absorbed into root hair cells.
How can you get soluble nitrogen?
From ammonium ions and nitrate ions
How can you get soluble phosphorus?
By mining phosphate ions.
How do you get potassium ions?
By dissolving all common potassium compounds in water.
What does potassium do?
It promotes flower and fruit production and protects against diseases.
What does nitrogen do?
It encourages leafy growth and stem formation.
What does phosphorus do?
It is used for seed growth and root development.
What are the advantages of NPK fertilisers?
- widely available
- easier to use
- don’t smell
- more nutrients
What is corrosion?
A natural process in which metals are gradually destroyed by reacting with substances in the environment. One example of this is rusting.
What is the equation for rusting?
Iron + water + oxygen = hydrated iron (III) oxide
How does aluminium corrode?
- Aluminium reacts with oxygen in the atmosphere in the presence of water.
- A layer of hydrated aluminium (III) oxide is formed.
- This layer is very stable and remains as a protective layer
What is the equation for the corrosion of aluminium?
Aluminium + water + oxygen = hydrated aluminium (III) oxide
How can you prevent corrosion?
- coating of paint/ grease/ electroplating
- galvanising (coat metal with a more reactive metal)
What happens if a galvanised nail gets scratched?
No rusting will occur
What is a gold alloy made out of?
Gold and copper
