Disregarding Products and Focusing on Reactants

$\frac{d[R]}{dt}=-k[R]^{2}; \frac{1}{[R]}=kt + \frac{1}{[R]_{0}}; t_{\frac{1}{2}}=\frac{1}{k[R]_{0}}$

Maggie Miller 2K
Posts: 11
Joined: Fri Jun 17, 2016 11:28 am

Disregarding Products and Focusing on Reactants

I am still a little confused on why exactly you can disregard the products that are formed and just focus on the reactants in order to get the rate. It is just a little conceptually difficult to wrap my mind around, so maybe someone could explain!

Thanks for the help!

garrett_perozich
Posts: 15
Joined: Wed Sep 21, 2016 2:57 pm

Re: Disregarding Products and Focusing on Reactants

If you take a look at page 59 in the course reader, we aren't really "ignoring" the products. As seen at the top of the page, the rate that the reactants decrease is equal to the rate that the products increase (with the opposite sign). Also, it is easier to study an initial reaction when very little product is present, so the reaction rate depends only on [R]. In sum, it simply makes the analysis easier. Dr. Lavelle goes into this in the course reader.

GregoryPolyakov_1H
Posts: 16
Joined: Wed Sep 21, 2016 2:56 pm

Re: Disregarding Products and Focusing on Reactants

If we're only worrying about the rate of reaction going forward, then iirc the reactants matter more since that's what the eventual concentration of the products relies on