Exam 3: Question 6


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Angel R Morales Dis1G
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Joined: Sat Jul 22, 2017 3:01 am

Exam 3: Question 6

Postby Angel R Morales Dis1G » Thu Mar 15, 2018 8:00 pm

How would we determine which rate constant to use given the following facts: 1st order reaction, proceeds for 10 minutes and that only 71.9% of the initial concentration of reactants remain.

Nha Dang 2I
Posts: 53
Joined: Fri Sep 29, 2017 7:07 am

Re: Exam 3: Question 6

Postby Nha Dang 2I » Thu Mar 15, 2018 10:08 pm

You would use ln([A]t/[A]0)=-kt with [A]t=.719[A]0

Then, you would can cancel out [A]0 in ln(.719[A]0/[A]0)=-k(10 minutes) and solve for k from there.

Jonathan Tangonan 1E
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Joined: Sat Jul 22, 2017 3:01 am

Re: Exam 3: Question 6

Postby Jonathan Tangonan 1E » Thu Mar 15, 2018 10:18 pm

If you were to use the integrated rate law for the constant you could determine it by substituting for the concentration at time t with (.719)(initial concentration) and then isolate k from there.

ln[A]= -kt + ln[Ainitial]

ln(.719[Ainitial]) - ln[A] = -kt

ln[.719[Ainitial]/[A]] = -kt

-ln[.719]/10min = k


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