button: text-only site map

Question

Explain, from the information given in the diagram:

why is the catalysed reaction faster than the gas phase reaction?

Is the overall process exothermic or endothermic?

Does the catalyst affect the equilibrium position?

button: providing answer to question
Energy Changes in the Catalysed Reaction
graph: activation enerygy
image:: Carl Bosch
Carl Bosch
Joint winner of Nobel Prize for Chemistry, 1931 for his work on high- pressure systems

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The red arrows in the diagram show the activation energies of each of the steps. The exact values vary depending on the surface coverage.
Success in manufacturing ammonia depended on finding a catalyst, but equally vital was the ability to put a high-pressure process safely into practice, and much of this success was due to Carl Bosch. Pressures used were around 250-350 atm but since 1960 there has been a steady fall in the synthesis pressure used.