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Integrated Rate Laws

Posted: Fri Mar 02, 2018 7:07 pm
by William Lan 2l
How do we relate -d[A]/dt with k[A]? Basically, why are they equal to each other? And what's the difference between integrated rate laws and just rate laws in general?

Re: Integrated Rate Laws  [ENDORSED]

Posted: Fri Mar 02, 2018 9:09 pm
by Sohini Halder 1G
Say A is your reactant. As the reaction progresses, A decreases (if first order, it decreases exponentially). Therefore, the rate is the negative change of the concentration of A over time, given by -d[A]/dt. This is equivalent to saying that the rate of the reaction is proportional (with a proportionality constant of k) to the concentration of A, given by k[A]. These inherently say the same thing so we can relate them by an equal sign. Once you integrate both sides, you get your integrated rate law.