Topic 6: Reversible Reactions, Industrial Processes and Important Chemicals Flashcards
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What is a reversible reaction?
A reaction which can go in reverse order as well.
The products of the reaction can react together to produce the original reactants.
What is ammonia?
A clear, gaseous, alkaline compound of nitrogen and hydrogen.
What are 3 uses of ammonia?
Explosives
Cleaning products
Fertilisers
What is the test for ammonia gas?
Turns damp red litmus paper blue (as litmus paper detects acidity/alkalinity)
What is the test for ammonium ions?
Ammonium ions found in compounds like ammonium chloride.
Add sodium hydroxide and heat gently, producing ammonia gas.
What is the Haber Process used for?
To collect ammonia.
What is the Haber Process equation?
Nitrogen + hydrogen ⇌ ammonia
N₂ + 3H₂ ⇌ 2NH₃
How is nitrogen obtained for haber process?
Found in air (78%=nitrogen)
How is hydrogen obtained for haber process?
Reacting natural gas (mostly methane) with steam, or from cracking fractions.
CH₄ + 2H₂O -> CO₂ + 2H₂
What are the conditions for the haber process?
High temperature - 350 - 450°C
High pressure - 150 - 200 atm
Iron catalyst
What happens to unreacted nitrogen and hydrogen?
As it is a reversible reaction, it can be recycled.
Why must we compromise for pressure conditions in the haber process?
Increasing = increased yield
Too high = expensive unsafe.
Why must we compromise for temperature conditions in the haber process?
Increasing = decreases yield
too low = slow rate of reaction (reason for iron catalyst)
What is the contact process used for?
To collect sulfuric acid.
What are the raw materials used in the contact process?
Sulfur
Air
Water
What are the 4 stages to the contact process?
1. Sulfur burned in air Sulfur + oxygen -> sulfur dioxide (cause of acid rain) S + O₂ -> SO₂ 2. More oxygen added sulfur dioxide + oxygen ⇌ sulfur trioxide 2SO₂ + O₂ ⇌ 2SO₃ 3. Sulfuric acid added Sulfur trioxide + sulfuric acid -> oleum SO₃ + H₂SO₄ -> H₂S₂O₇ 4. water then added oleum + water -> sulfuric acid H₂S₂O₇ + H₂O -> 2H₂SO₄
What are 4 uses of sulfuric acid?
fertiliser
paints and dyes
dehydrating agent
car batteries
What will happen when you add sulfuric acid to hydrated copper (II) sulfate?
Hydrated copper (II) sulfate = blue adding sulfuric acid = white - anhydrous copper (II) sulfate
What will happen when you react sulfuric acid with glucose?
Concentrated sulfuric acid + glucose -> carbon
Dehydrates glucose and only leaves pure carbon - black.
What are in the most effective fertilisers?
Nitrogen (from ammonia compounds) because plants need it in order to produce proteins.
Phosphorus and potassium are also essential elements commonly found in fertilisers.
What are 3 advantages of artificial fertilisers?
Increases crop growth
Increases crop yield
Better soil quality
What are 3 disadvantages of artificial fertilisers?
Causes eutrophication - fertilisers pollute waterways
Causes blue baby syndrome
Turns the soil acidic
