Question

Describe the different ways to shift the equilibrium to the left for the following reaction:

2 A (s) + 2 BC (aq) ↔ 2 AB (aq) + C2 (g). Justify your answer. ΔH = −352 kJ

Answer 1

2ABC (aq) ↔ 2 AB (aq)
This is how I thought it should be, I feel like I'm horribly wrong. But, I combined the A and BC, and eliminated C2. I don't understand how to 'justify' this beyond that though. Anyone know how to do this?

Answer 2

i think it's asking you to apply le chateliers principles to drive the equilibrium forward.

Answer 3

How would I do that?

Answer 4

Apply the principles, for example, the reaction is exothermic, so reducing the temperature of the reaction mix will drive the reaction forward.

Answer 5

Ok. So, the ΔH = −352 kJ, this is the temperature?

Answer 6

no thats the enthalpy change, a negative value corresponds to an exothermic process.

Answer 7

Could you guide me through how to do this?

Answer 8

Do you know le chatelier's principles?

Answer 9

I am reading them now, through chem wiki. I've been trying to figure this out.

Answer 10

If I could figure out this equation, I think I could understand how to do the others.

Answer 11

How do I find the temperature of this equation? The one in the chem wiki example is 500C

Answer 12

This says to move to the left, we increase the temp?

Answer 13

the direction it will move when you change the temperature depends on whether the reaction is exo- or endothermic.

If it's exothermic, raising the temperature will drive the reaction in the backward direction.

Answer 14

ok. How would I do this?

Answer 15

so to drive the reaction to the left, raise the T

Answer 16

I'm sorry, but I don't understand how to know what is the temp, if 352 is the enthalpy, how do I know what temp is?

Answer 17

you don't know and it doesn't matter because regardless of what T the reaction is at, increasing the T will drive the equilibrium to the left.

Answer 18

ok.

Answer 19

i hope you don't think I'm being harsh, I'm just being direct.

Answer 20

No, I just hope you don't think I'm not trying to understand. I just don't get it yet.

Answer 21

Ok, so, do I need to re-write the equation as if I increased the temp?

Answer 22

okay, yeah no problem.

nope, the equation doesn't change.

What this question is asking of you is to provide changes to the conditions to shift it left.

So you can say, increase T

you can also change the concentrations of products or reactants accordingly.

You can change the pressure (when working with gases)

Answer 23

You should first list all the parameters you can change to shift the eq. according to Le chatelier's principles.

Answer 24

and have those as a reference. This will make this question, like, really easy.

Answer 25

Ok.
I was going to write something like:
Way in which we can shift the equilbrium to the left, would be to
increase/decrease temperature depending on exothermic or endothermic reaction.
Also increase/decrease pressure (when working with gases)
and also, changing concentrations accordingly.

Answer 26

What do u think?

Answer 27

those are good guidelines, but not specific to the question.

Answer 28

what am I missing?

Answer 29

you're not saying what you should do to the reaction to shift it left.

Answer 30

you need specific statements, like, "the reaction is exothermic, and so increasing the temperature would shift it left."

Answer 31

Ok. I was looking at the problem all wrong.

Answer 32

Thank you for all the help.

Answer 33

no problem. review the principles, and if you still have problems post your doubts.