Equilibrium Reactions - Help yeah? (1 Viewer)

[The-Exiled]

Okay, so I don't really understand this whole thing... Like for example with Ammonia production:

N2(g) + 3H2(g) <--> 2NH3(g) + (Heat)

SO, with an increase in temperature the reaction should shift left...? because if you add heat, which is already a product it shifts to try and make more reactants...?

And... using Le Chanteliers principle that if theres more moles of gas on the left side... (4 v 2) then it should shift to the right? Don't know why... But yeah... is that right?

Is there any other reasons why it would shift in any direction? Except for obviously adding more reactant? :S

 

[tegzy26]

increasing the temperature would yes shift the equilibrium to the left (favouring the reactants) but it also increases the rate of reaction. at normal temp and pressure the haber process does not yeild much ammonia, hence the the temp is increased.
an INCREASE in PRESSURE cause the equilibruim to shift to the right, this is done to speed up the rate of reaction.
the reason the increase in pressure changes the equilibrium shift is because in gases increasing the pressure increases the concentration of molecules by forcing them closer together making the chance of collision higher, more collision gives a highr reaction rate
hope this helped

 

[tommykins]

回复: Equilibrium Reactions - Help yeah?

Le Chatelier's principle states that if a change is imposed on an equilbrium system, the system will adjust itself to minimise the change.

Increase in temperature will cause the system to reduce the temperature, since the forward reaction is exothermic, to reduce the temperature the endothermic reaction has to occur more frequently, thus it shifts to the left (reverse reaction).

Increase in pressure will cause the system to want to decrease the pressure. It does so by producing less moles of gas, hence favouring the side with the least moles of gas which is the forward reaction.

 

[The-Exiled]

Ah okay, thanks for that.