The Haber Process Question (1 Viewer)

[zinzins]

I think it was question 27, anyways howd u guys go about answering that one? It was the one where u had to draw the graph and state what happened to the molar concentration when the volume was decreased or something. I think I may have screwed up.....

 

[Dumsum]

When the volume was decreased that increases pressure so the reaction would favour ammonia production. So I continued ammonia upwards and nitrogen and hydrogen downwards.

 

[gogogadgetbrain]

NH4 went up
H2 and N2 went down
and then they all went straight...indicating an equilibrium was again established

 

[Firnovvwen]

Crap.

I totally fucked that question then.

 

[Captain Gh3y]

Question for maths/chemistry people...

I know H2 and N2 went down, and NH3 went up, but should the curves have been concave up or concave down?

I had the H2 and N2 curves concave up, and the NH3 curve concave down.

 

[gogogadgetbrain]

im pretty sure they should be similar to the ones at the start of the graph
ie concave up for ammonia
concave down for hydrogen and nitrogen

 

[~ ReNcH ~]

Question for maths/chemistry people...

I know H2 and N2 went down, and NH3 went up, but should the curves have been concave up or concave down?

I had the H2 and N2 curves concave up, and the NH3 curve concave down.

I had the same shape as they were originally...
Btw. did your new curve start at T2, just to make sure i.e. it was kind of one curve drawn on top of the other?

 

[Captain Gh3y]

I'm not sure what you mean, I had the curve I drew connecting up with the printed curve at T2.

 

[~ ReNcH ~]

I'm not sure what you mean, I had the curve I drew connecting up with the printed curve at T2.

Hmm, ok. Nvm. I just wasn't too sure what the curve actually looked like.

 

[jynxe]

I thought there would be a straight vertical jump at first, because when the pressure increases there is an immediate volume drop, and with C=n/V there comes a corresponding immediate increase in concentration for all 3 species?

But I did the question wrong, I read it as INCREASING the volume and thus decreasing pressure, so everything I did was opposite.

 

[zinzins]

When the volume was decreased that increases pressure so the reaction would favour ammonia production. So I continued ammonia upwards and nitrogen and hydrogen downwards.

alright, so the question refered to the decrease in the volume of the container the reactants were in, so that meant an increase in pressure thus favouring the production of ammonia.

I thought it said that the actual volume of the gases of the reactants was decrease, meaning that the pressure in the reactant chamber dropped. That would then mean that the equilibrium would favour the reverse reaction to increase the pressure.

u sure thats wat it meant? So confused!

 

[jynxe]

I thought the question was something like: (Actually I don't know at all because I misread the question completely so I can't remember, but from what I've heard since it seems as though..)

The total volume of the chamber was decreased, causing an increase in pressure. The increase in pressure favours the products.

Is that what the question was? I have no idea since I myself read it wrong =P

 

[gogogadgetbrain]

yeah i just put a side note on how i interpreted the question

 

[ishq]

NH4 went up
H2 and N2 went down
and then they all went straight...indicating an equilibrium was again established

Yeah, that's what I did. With like a 'T3' for when the next equilibrium was established. You could explain what you interpreted the question to mean (less volume = more pressure) in the following 2 marker...right?

 

[Dumsum]

Yeah, that's what I did. With like a 'T3' for when the next equilibrium was established. You could explain what you interpreted the question to mean (less volume = more pressure) in the following 2 marker...right?

The whole thing was two marks wasn't it? Like draw the graph and explain the graph was in the same question. So 1 mark for the graph and 1 mark for the explanation.

 

[rama_v]

The whole thing was two marks wasn't it? Like draw the graph and explain the graph was in the same question. So 1 mark for the graph and 1 mark for the explanation.

I think it was 2 for the graph and 2 for the explanation

 

[~ ReNcH ~]

What did write for the explanation? I just wrote the equation for the Haber process, referred to Le Chatelier, and stated that the concentration of ammonia would increase and that the concentration of nitrogen and hydrogen would decrease as a result of the increase in pressure. I can't remember if I referred to the system returning to equilibrium...I wonder if I'd lose a mark for failing to acknowledge this last point...?

Btw. if it's no trouble, can someone who's confident that they got the graph write post it up? I'm still a bit unsure as to whether mine is strictly correct...

 

[hobbsy4]

We got the exact same question in our trial
I got full marks in the trial for it, some have already said the correct answer in this thread with N2 and H2 decreasing, NH3 rising and then equilibrium established again.

 

[seadonkey]

ur all wrong.... wen volume decreases conc of ALL reactants increase as
conc proportional to moles/volume

the 3 conc then curve
NH3 curve concave down
H2 and H2 concave up

 

[Captain Gh3y]

My answer.

My explanation:

As the volume of the container is decreased, the pressure on the system is increased. N2 + 3H2 <--> 2NH3. The reaction that produces the least number of moles of gas will be favoured. Hence, more ammonia will be produced. The equilibrium moves to the right.