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# Rates of reaction question watch

1. Damn Imperial for sending me some work to do before starting. Don't they know after 15 weeks of holiday work is impossible?

Anyway

(Original post by Question)
Suppose a reaction occurs with the following mechanism

(fast)

(slow)

a) Write the rate law for the forwards reaction in step 1
b) Write the rate law for the backwards reaction in step 1
c) Write the rate law for the rate determining step
d) What is the Chemical Equation for net reaction that occurs in this chemical change?
e) Write the rate law of the net reaction in terms of the concentration of the reactants in the overall balanced equation for the reaction
f) What would be the reate law for the overall reaction if step 1 occurred slowly and step 2 was fast?
I have forgotten my entire A level course on this! Can anybody point me in the correct direction. For part a) the answer Rate=k[A] comes to mind, but I don't think it's right. After that I'm lost.
2. lol oh dear mate...

a/ r=k.[A]^2

b/ r=k.[A2]

c/ r=k.[A2].[E]

d/ 2A + E -> B + C

e/ r=k.[A]^2.[E]

f/ r=k.[A]^2

Not sure on e and f; you should be ashamed.
3. where x is the order and k1 is the rate constant for the forward reaction

b) is similar
c) is a combination of a) and b)
d) rewrite the two equations as one
e) now write the rate law for this single reaction
f) bit more involved
4. (Original post by EierVonSatan)
where x is the order and k1 is the rate constant for the forward reaction

b) is similar
c) is a combination of a) and b)
d) rewrite the two equations as one
e) now write the rate law for this single reaction
f) bit more involved
So I should just write it as you've said, seeing as I don't have the order of reaction?
5. (Original post by IChem)
So I should just write it as you've said, seeing as I don't have the order of reaction?
yeah I would
6. Cheers for that. All sorted now, I hope.
7. so for c) I have

Where k-1 is the backward rate constant.

For more detail we can assume that the concentration of A2 is 0 at t = 0 and can therefore write [A2] = [A0] - [A] where [A0] is the initial concentration of A etc. This allows you to plot a graph y = mx + c...but I'm rambling
8. Cheers for all your input. However, seeing as I am not particularly clear on this topic, I will have to bring it to the attention of my tutor at Imperial. The piece of work I'm doing isn't to be assessed it's what they are calling a "survey" to see what we can and can't do.
9. (Original post by IChem)
Cheers for all your input. However, seeing as I am not particularly clear on this topic, I will have to bring it to the attention of my tutor at Imperial. The piece of work I'm doing isn't to be assessed it's what they are calling a "survey" to see what we can and can't do.
Okay, sorry for confusing you there - I've answered the question to first year degree level (i.e. replacing rate with the differential) so don't worry if you've never seen it in this form before
10. (Original post by EierVonSatan)
Okay, sorry for confusing you there - I've answered the question to first year degree level (i.e. replacing rate with the differential) so don't worry if you've never seen it in this form before
Lol, don't worry about it. I'm sure it will all be made clear to me soon!
11. the OP of this thread makes me want to cry
12. (Original post by Malsi101)
the OP of this thread makes me want to cry
Why?
13. (Original post by IChem)
Why?

it's too hard

what level is it *sobs*
14. (Original post by Malsi101)
it's too hard

what level is it *sobs*
It's between A2 and first year degree level, so don't panic

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Updated: September 24, 2008
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