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Topic: Buffer value and capacity  (Read 2342 times)

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Offline pattyg

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Buffer value and capacity
« on: March 23, 2011, 12:55:44 PM »
What would be the pH of a 0.01 M solution of Ammonium Hydroxide with a pKb of 4.6

Determine the pH of this solution
10.7

Determine the buffer value of this solution
I thought this would be 5.75x.01M but that is not the correct answer

Determine the buffer capacity
and i don't get this one because i would need a initial pH?
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Offline Nobby

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Re: Buffer value and capacity
« Reply #1 on: March 25, 2011, 02:12:19 AM »
pOH = 1/2*(pkb -log(cb))

pOH = 0.5*(4.6-log(0.01))

pOH = 3.3

pH =14-pOH

pH = 10.7

should be correct

But for a buffer you need also ammonium salt.
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Offline Borek

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Re: Buffer value and capacity
« Reply #2 on: March 25, 2011, 05:09:52 AM »
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