## Rate constant depends on what concentration change you want?

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### Rate constant depends on what concentration change you want?

Is it always the overall order of the reaction that dictates what the units of k are (thus focusing on the rate of product formation)? I guess what I'm trying to get at is whether the rate constant changes depending on which concentration change you are trying to calculate- either the loss of reactant A, or the gain of product B.

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### Re: Rate constant depends on what concentration change you w

When we study a reaction, we typically study the initial reaction rate when there is almost no reverse reaction, and that's how rate constant k is defined: we re-express rate in terms of rate constant, k and [R] after doing experiments to observe d[R]/dt. Because your initial reaction rate only depends on reactant, the rate constant k, also only depends on the reactant.