5% Rule and % Deprotonation

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Layal Suboh 1I
Posts: 61
Joined: Fri Sep 28, 2018 12:23 am

5% Rule and % Deprotonation

Postby Layal Suboh 1I » Thu Jan 24, 2019 3:03 pm

Hello,

Is the 5% rule calculated the same way as percent deprotonation/protonation?

Christopher Tran 1J
Posts: 77
Joined: Fri Sep 28, 2018 12:15 am

Re: 5% Rule and % Deprotonation

Postby Christopher Tran 1J » Thu Jan 24, 2019 3:13 pm

Yes, if the percent deprotonation is less than 5%, then you are safe to approximate by assuming that a change of 0.1-x, for example, is 0.1.

mbaker4E
Posts: 69
Joined: Fri Sep 28, 2018 12:26 am

Re: 5% Rule and % Deprotonation

Postby mbaker4E » Thu Jan 24, 2019 4:22 pm

Yes, they both use change in concentration over initial concentration times 100%

Ethan Baurle 1A
Posts: 33
Joined: Fri Sep 28, 2018 12:19 am

Re: 5% Rule and % Deprotonation

Postby Ethan Baurle 1A » Thu Jan 24, 2019 4:39 pm

Just for future reference and ease on test problems, any time the constant value is lower than 1 x 10^-3 it should be safe to use an approximation. You can use the % deprotonation rule to check afterwards if you are worried, but this will save you some time on exams.


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