ODE question, appreciate your help

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Homework Help Overview

The discussion revolves around a question related to ordinary differential equations (ODEs) in the context of a reversible chemical reaction. Participants are exploring the formulation of the rate equations and the implications of certain constants in the equations.

Discussion Character

  • Exploratory, Conceptual clarification, Problem interpretation

Approaches and Questions Raised

  • The original poster attempts to formulate the differential equation but expresses confusion about the presence of certain constants. Other participants suggest using conservation of mass and question the necessity of specific terms in the equation.

Discussion Status

Participants are actively engaging with the problem, offering suggestions for reframing the equation and discussing the implications of the constants involved. There is a recognition of the need for clarity regarding the problem's context, indicating a productive direction in the conversation.

Contextual Notes

There are constraints mentioned regarding the requirement to show specific terms in the equations, and participants note the potential confusion arising from the problem's presentation. The lack of clarity about the source material is also highlighted as a factor in understanding the question.

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Can anyone give me a hand with this question? I honestly have no idea how to do it?

I was thinking for d(A)/dt=-d(B)/dt= -k1(A)+k-1(B) because the 2 on both sides cancels out? But this was completely wrong...

Any ideas? :)
 
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zibb3r said:
View attachment 62034

Can anyone give me a hand with this question? I honestly have no idea how to do it?

I was thinking for d(A)/dt=-d(B)/dt= -k1(A)+k-1(B) because the 2 on both sides cancels out? But this was completely wrong...

Any ideas? :)

The equation of the most elementary reversible chemical reaction. Your equation is OK. Just use conservation of mass which enables you to get the equation in one dependent variable only.

I don't see the point of the 2 either*. I suggest you reframe it as A ⇔ B with the rate constants half those given.

Since this seems meant to trip students up, I suggest you placate them by using the symbols they ask, a and b.


* Unless by any chance the context suggests they mean a mechanism in which two molecules of A collide and transform into something that rapidly dissociates into two molecules of B, in which case the d.e. would be different. However if you have never done the more elementary one before then are unlikely to mean this.
 
Last edited:
Thanks but apprantley I have to show it fully as in can't can have it that way/have to show the 2s. Do you have any clue how Id write it that way?
 
zibb3r said:
Thanks but apprantley I have to show it fully as in can't can have it that way/have to show the 2s. Do you have any clue how Id write it that way?

I can't offer more than
zibb3r said:
I don't see the point of the 2 either*. I suggest you reframe it as A ⇔ B with the rate constants half those given.
.
plus my *footnote in post.

Sometimes here we have to spend too much time on exegesis, working out what a question could possibly mean. This looks like a printed text, if we saw more of where it came from, e.g. the textbook section, or the section on which it is an exercise, we'd know better what the problem is.
 

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