Flashcards in C2e-manufacturing Chemicals: Making Ammonia Deck (18)
What is the word equation for the haber process?
Nitrogen + hydrogen --> ammonia
What are the conditions needed for the haber process?
What is the balanced symbol equation for the haber process?
N2 + 3H2 --> 2NH3
What happens to the unreacted nitrogen and hydrogen?
They are recycled
How does a high pressure effect the percentage yield?
Increase percentage yield
Favour forward reaction
High pressures dangerous and expensive
How does a high temperature effect the percentage yield?
Favour reverse reaction
Decrease percentage yield
Low temperatures slow reaction rates
High rate of reacion
Why is 450c used?
Fast reaction rate
Reasonable percentage yield
What does an iron catalyst do?
Increases rate of reaction
Keeps costs down
Doesn't change percentage yield
What does the cost of making a new substance depend on?
Price of energy
Cost of starting materials
How quickly substance can be made(cost of catalyst)
What is automation?
Putting robots in to make things
How do high pressures affect production costs?
Higher plant costs
How does high temperatures affect the production costs?
High energy cost
How does a catalyst affect the costs?
Reduces cost by increasing rate of reaction
How does automation affect costs?
Reduces wages bill
How do economic considerations determine the conditions used in the manufacture of chemicals?
-Rate and percentage yield must be high enough to give sufficient daily yield of product
-Low percentage yield can be accepted if reaction can be repeated alot with recycled starting materials
-optimum conditions used that give lowest cost rather than fastest reaction/ highest percentage yield
What is a reversible reaction?
A reaction that proceeds in both directions
What are the uses of ammonia?
Manufacture of fertilisers
Manufacture of nitric acid