the rate graph in exam

[kdgamz]

How can it be removal of product, if u remove the product it'll shift forward, and the rate of forward reaction would increase. But it didnt, it decreased.

removing product measn theres less of it so the back reaction is not as significant....i think?

[monokekie]

buut didnt the back reaction increase???

When water has been added to the equilibrium system, the graph shows that the back reaction initially decreased significantly, then gradually increased at the similar rate the forward reaction decreases.

The reason being that as the system re-established equilibrium, more product has been formed, concentration of the product has increased, thus the rate of the backward reaction increases gradually. Also , the mole reactant has been decreased in this process of re-establishing equilibrium system, the concentration has alsbo been decreased, hence the forward reaction has been decreased gradually.

The forward reaction and the backward reaction eventually adjust to the same rate, where the equilibrium has been re-established. According to the definition of the equilibrum system, the rate of the forward reaction equals the the back reaction.

As to the next question, the equilibrum constant thus does not change after this change. ( Temperature is the only factor that may alter the Keq value of a system)

[magnum]

I said removal of product

same

So is it removal of products? 

[monokekie]

How can it be removal of product, if u remove the product it'll shift forward, and the rate of forward reaction would increase. But it didnt, it decreased.

removing product measn theres less of it so the back reaction is not as significant....i think?

whereas the forward reaction increased sigficantly. which means there would be an instantaneous increase in the forward reaction, and the graph indicates otherwise

[TheJosh]

How can it be removal of product, if u remove the product it'll shift forward, and the rate of forward reaction would increase. But it didnt, it decreased.

removing product measn theres less of it so the back reaction is not as significant....i think?

whereas the forward reaction increased sigficantly. which means there would be an instantaneous increase in the forward reaction

the back reaction increased...as a result of removal of product...dusnt that make more sense??..

[crappy]

awwww fuck, i said removal of ammonium

[hedz]

I think it has to be the dilution thing, because there are only three ways to cause all the reaction rates to decrease:
Lower pressure (not gas)
Change Temp (cant..)
Lower Concentrations.
So it has to be dilution

[monokekie]

soz hedz i just confuzed myself enormously. silly me, wrote it when i was on the phone.  i was re-reading that post and could understand it myself.. soz lol

[rajah21]

Dammit! How many marks was that question?

[crappy]

Dammit! How many marks was that question?

2 marks

[tommyk221]

The answer is either the removal of product, or apparently the addition of a base.

I put neither of them, so meh.

Yeah I said addition of a base...

[/0]

Wouldn't the base also react with ammonium ions though?

[tommyk221]

Wouldn't the base also react with ammonium ions though?

Probably, I wasn't really sure haha

[silva]

tsfx had a question in one of their exams that had the exact same graph shape and behaviour of the forward and back reaction, and that was for a dilution to an equilibrium system

[lukeperry91]

I said addition of a strong base