Deriving the Rate Laws

$aR \to bP, Rate = -\frac{1}{a} \frac{d[R]}{dt} = \frac{1}{b}\frac{d[P]}{dt}$

Abigail Urbina 1K
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Deriving the Rate Laws

When we are deriving the rate laws, does it matter whether we use definite or indefinite integrals? Will we be able to come to the same rate law equations if we use either definite or indefinite integrals? When do we know what is appropriate to use/what we should use?

nathansalce 3e
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Joined: Thu Jul 27, 2017 3:01 am

Re: Deriving the Rate Laws

I think since the derivation of the equation speaks in general terms and has no specific definite value to integrate for, much like all the derivations we have done. I think all of our derivations thus far have been indefinite integrals meaning we are just integrating the variables, which is the important part.

Vincent Tse 1K
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Re: Deriving the Rate Laws

In a general sense, it doesn't particularly matter if you use definite or indefinite integrals. All a definite integral does is specify the bounds of integration. You should be able to come to the same equations using both--I think Dr. Lavelle did it in class with indefinite, and the textbook uses definite (for the most part). You use definite integrals whenever you specifically want to integrate in a certain range.

Andrew Nguyen 2I
Posts: 68
Joined: Fri Sep 29, 2017 7:07 am

Re: Deriving the Rate Laws

I think the slides in class have been using indefinite integration; though there are a lot of sources which tell you how to get the same equation with definite integration. For the most part the algebra and calculus is very similar up to the last step. Nonetheless, both ways can give you the same equation- depending on which is easier for you, you should use that method.