April 27, 2024, 05:31:23 PM
Forum Rules: Read This Before Posting


Topic: calculationg actual concentration given pH and total concentration  (Read 3259 times)

0 Members and 1 Guest are viewing this topic.

Offline whatisbarium2sodium

  • New Member
  • **
  • Posts: 5
  • Mole Snacks: +0/-0
  • Gender: Male
Im not sure on how to approach the problem.
Assuing the reaction is

HC3H3O2  ::equil:: H+  + C2H3O2-

used the measured pH (2.42) and the total concentration (.1M) to calculate the actual concentration of each species.

Im not really sure where to start on this problem. please give me a push. i dont want the answer. just a hint on where to start.
thankyou for helping.

Offline JustinCh3m

  • Regular Member
  • ***
  • Posts: 95
  • Mole Snacks: +12/-8
    • CollegeChemistryNotes
Re: calculationg actual concentration given pH and total concentration
« Reply #1 on: March 31, 2012, 04:14:04 PM »
Are you familiar with the "I.C.E. method" and do you know how to write an equilibrium expression for a weak acid? 

Offline whatisbarium2sodium

  • New Member
  • **
  • Posts: 5
  • Mole Snacks: +0/-0
  • Gender: Male
Re: calculationg actual concentration given pH and total concentration
« Reply #2 on: March 31, 2012, 05:40:05 PM »
no i dont.. ive never heard of that. im going to look it up in my book

Offline AWK

  • Retired Staff
  • Sr. Member
  • *
  • Posts: 7979
  • Mole Snacks: +555/-93
  • Gender: Male
Re: calculationg actual concentration given pH and total concentration
« Reply #3 on: March 31, 2012, 05:49:47 PM »
Im not sure on how to approach the problem.
Assuing the reaction is

HC3H3O2  ::equil:: H+  + C2H3O2-

used the measured pH (2.42) and the total concentration (.1M) to calculate the actual concentration of each species.

 
For acetic acid you never get pH=2.42. For 0.1 M acetic acid pH at room temperature is close to 2.9.
AWK

Sponsored Links