Haber Process and Equilibrium (1 Viewer)

[serge]

Hey people

Is it true that industrially the Haber process is never at equilibrium?
because if you liquefy the produced ammonia and move it away from
the reaction vessel it stops being a system at equilibrium?

the older Excel textbook explained it this way, but others seem
to neglect the idea

any thoughts?

 

[Casmira]

there was a HSC question asking that in the 2001 HSC
i had wrote that it would of increased forward reaction because you need to cool it alot to make it liquid, but the answer said forward anyway, but due to the ammonia in gas state is in less concetration so forward reaction is favoured to counteract the change

i imagine it'd be very hard/impossible to get ammonia at 100% yield, so if about 80% if the yield, if you remove 80% of that, you still got 20% of unreacted nitrogen and hydrogen that form equilibrium, but since they are at equilibrium they favour forward

 

[Dreamerish*~]

Hey people

Is it true that industrially the Haber process is never at equilibrium?
because if you liquefy the produced ammonia and move it away from
the reaction vessel it stops being a system at equilibrium?

the older Excel textbook explained it this way, but others seem
to neglect the idea

any thoughts?

Probably, as they keep removing the ammonia as it forms.

But that doesn't mean the equilibrium doesn't exist. When we talk about it in the exam, we describe it using an equation and explain why the products are removed as they form, why the temperature is not too high, why the pressure needs to be high, etc. It's all related to the equilibrium, regardless of whether or not the process is at equilibrium or not.

 

[serge]

thanks, i get it
plus there's no point mentioning something this technical if the syllabus wants
you to explain it as an equilibrium reaction anyway

 

[sikeveo]

You keep removing the ammonia so it wont shift the other way.

 

[lozabella]

the haber process is always in equilibrium because it will never be driven to completetion....the thing that changes however is the position of the equilibrium in order to maximise the yield. The issues however is that becasue it's exothermic a increasing the temp would make the reaction occur faster, however it would also push equilibrium position left, making more of the products. The pressure is increased so that the equilibrium position shifts right from 4 moles of gas to 2 moles of gas. To overcome the temp and reaction rate problem a catalyst Fe3O4 is used whicih lowers the activation energy. Thus the idea is to have moderate temperature going moderately quickly producing moderate yield. But yeh, essentially i guess the point is that the haber process is in equilibrium, and will never go to completion.