November 30, 2020, 03:39:21 AM
Forum Rules: Read This Before Posting


Topic: Buffer question  (Read 169 times)

0 Members and 1 Guest are viewing this topic.

Offline sharbeldam

  • Full Member
  • ****
  • Posts: 228
  • Mole Snacks: +6/-0
Buffer question
« on: November 21, 2020, 05:11:06 PM »
I did A.

But about B:
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.
O-Chem 1+2 Online Free tutor on Skype: Live:damnitsjake21

Offline Borek

  • Mr. pH
  • Administrator
  • Deity Member
  • *
  • Posts: 26151
  • Mole Snacks: +1702/-402
  • Gender: Male
  • I am known to be occasionally wrong.
    • Chembuddy
Re: Buffer question
« Reply #1 on: November 21, 2020, 05:52:29 PM »
Assume protonation of sulfate is quantitative and follow the stoichiometry.
ChemBuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info, pH-meter.info

Offline sharbeldam

  • Full Member
  • ****
  • Posts: 228
  • Mole Snacks: +6/-0
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?
O-Chem 1+2 Online Free tutor on Skype: Live:damnitsjake21

Offline Borek

  • Mr. pH
  • Administrator
  • Deity Member
  • *
  • Posts: 26151
  • Mole Snacks: +1702/-402
  • Gender: Male
  • I am known to be occasionally wrong.
    • Chembuddy
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.

ChemBuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info, pH-meter.info

Offline sharbeldam

  • Full Member
  • ****
  • Posts: 228
  • Mole Snacks: +6/-0
Re: Buffer question
« Reply #4 on: November 22, 2020, 04:43:34 AM »
Thank you borek
we appreciate you and this site.
O-Chem 1+2 Online Free tutor on Skype: Live:damnitsjake21

Sponsored Links