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Topic: Buffer question  (Read 326 times)

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sharbeldam

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Buffer question
« on: November 21, 2020, 05:11:06 PM »
I did A.

I did calculate the moles of acid -> 0.01 moles of H+

I have 0.5L of my buffer (NaHSO4)

Can someone give me a hint of where to begin? I Did solve a few questions regarding finding out how much acid or base to add to buffer to get to a specific pH but this is different.
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Borek

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Re: Buffer question
« Reply #1 on: November 21, 2020, 05:52:29 PM »
Assume protonation of sulfate is quantitative and follow the stoichiometry.
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sharbeldam

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Re: Buffer question
« Reply #2 on: November 22, 2020, 01:46:07 AM »
but do i just assume at first, like for instance make a buffer with 0.5 mole of sodium bisulfate and 0.5 mole of its salt and then try if the pH changes less than 10% once i add the hcl?
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Borek

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Re: Buffer question
« Reply #3 on: November 22, 2020, 04:29:25 AM »
Assume the initial concentration is x and express the condition (not more than 10% change) using algebra and Henderson-Hasselbalch equation.

Then just solve for x.

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sharbeldam

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Re: Buffer question
« Reply #4 on: November 22, 2020, 04:43:34 AM »
Thank you borek
we appreciate you and this site.
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