How to find the integrated rate law?

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The discussion revolves around deriving the integrated rate law for a first-order reaction, starting from the rate equation r = -d[A]/dt = k[A]. The integration process is outlined, leading to the expression ln[A] + [A]0 = kt, which is questioned for its accuracy. Clarification is sought regarding the integration constant, specifically why it is ln[A]0, attributed to the integration limits from 0 to t. The correct form of the integrated rate law is confirmed as ln[A] = -kt + ln[A]0. Understanding the integration process and limits is crucial for accurately deriving the integrated rate law.
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Homework Statement



Find the integrated rate law for a first order reaction


The Attempt at a Solution



We have r = -d[A]/dt = k[A]

Integration with respect to [A] gives

[A] = (1/2)k*[A]^2

Is this it?
 
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d[A]/dt = k[A]

1/(k*[A]) . d[A] = dt

1/(k*[A]) . d[A] = t

now integrate left side ..

I am pretty sure that you have got it wrong
 
ln[A] + [A]0 = kt

Is this the correct form?
 
Last edited:
ln[A] + C = kt

Can anyone explain why the integration constant is ln[A]0?
 
that's due to the integration limits
{from 0 to t}
ln(A) is at t and ln[A]0 is 0
 
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