Topic 4b

Question 1

4.13
What does the symbol ⇌ tell you about a reaction?

Answer 1

Reversible

Question 2

4.13
What is a reversible reaction?

Answer 2

Able to go backwards & forwards

Question 3

4.13
Give a general answer on how the direction of a reversible reaction can be altered

Answer 3

Change reaction conditions

Question 4

4.14
Define the term dynamic equilibrium

Answer 4

-Forward & backward reaction occurs at same rate
-No overall change

Question 5

4.14
In what type of system does equilibrium take place in? Why?

Answer 5

-Closed
-If not, products will escape

Question 6

4.15
a) What type of reaction is the formation of ammonia?
b) What is the name of it?
c) What are the reactants?

Answer 6

a) Reversible
b) Haber process
c) Nitrogen & hydrogen

Question 7

4.15
State the chemical equation for the Haber process and which side is endothermic

Answer 7

N₂ (g) + 3H₂ (g) ⇌ 2NH₃ (g)
<–Endo Exo–>

Question 8

4.15
Where is nitrogen obtained from for the Haber process?

Answer 8

Extracted from air by fractional distillation

Question 9

4.15
Where is hydrogen obtained from for the Haber process?

Answer 9

From natural gas

Question 10

4.15
During the Haber process, how do we ensure that the reactants are not wasted?

Answer 10

Recycle them

Question 11

4.15
Why is ammonia removed from the process as it is formed?

Answer 11

-Reversible reaction
-Want to prevent ammonia turning back into H₂ & N₂

Question 12

4.16
What are the conditions used in the Haber process?

Answer 12

-Temp: 450°C
-Pressure: 200 atmospheres (atm)
-Iron catalyst

Question 13

4.16
a) What effect does an iron catalyst have on the rate of attainment of equilibrium?
b) What effect does the catalyst have on the equilibrium yield of ammonia?

Answer 13

a) Speeds it up
b) No effect

Question 14

4.16
Is the Haber process an endo or exothermic reaction?

Answer 14

Exo