October 31, 2024, 07:18:30 PM
Forum Rules: Read This Before Posting


Topic: Bronsted-Lowry acid/base theory question  (Read 6406 times)

0 Members and 1 Guest are viewing this topic.

Offline s3a

  • Regular Member
  • ***
  • Posts: 63
  • Mole Snacks: +0/-0
Bronsted-Lowry acid/base theory question
« on: April 26, 2009, 05:48:12 PM »
The answers are:

1) Base
2) Acid
3) Conjugate acid
4) Conjugate base

and I can memorize them for my quiz but I would like to understand what is going on so can someone explain it to me please? #1 looks to be an acid to me since it has hydrogen, #2 looks to be neutral since it's supposed to be H+ + OH-, #3 looks more acidic because of hydrogen and #4 looks basic as it is but I also don't understand what the word "conjugate" means.

Any help would be greatly appreciated!
Thanks in advance!

Offline Borek

  • Mr. pH
  • Administrator
  • Deity Member
  • *
  • Posts: 27820
  • Mole Snacks: +1808/-412
  • Gender: Male
  • I am known to be occasionally wrong.
    • Chembuddy
Re: Bronsted-Lowry acid/base theory question
« Reply #1 on: April 26, 2009, 06:02:13 PM »
Having a hydrogen is not the definition of an acid. Ability to give proton is. Ability to accept proton is a definition of Bronsted base.
ChemBuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info

Offline s3a

  • Regular Member
  • ***
  • Posts: 63
  • Mole Snacks: +0/-0
Re: Bronsted-Lowry acid/base theory question
« Reply #2 on: April 26, 2009, 08:45:24 PM »
How do you give a proton? Isn't a proton locked in the nucleus and electrons are the only particle that can travel from one atom to another?

Offline Arkcon

  • Retired Staff
  • Sr. Member
  • *
  • Posts: 7367
  • Mole Snacks: +533/-147
Re: Bronsted-Lowry acid/base theory question
« Reply #3 on: April 26, 2009, 10:11:11 PM »
The Bronsted-Lowry definition of acid is the ability to donate a proton.  At least, that's what we call it, we all know, like you do, that the nuclear physics of proton in the nuclei are more complicated than that.  Now, as an example, you wouldn't call heptane, C7H16, a Bronsted-Lowry acid, would you?
Hey, I'm not judging.  I just like to shoot straight.  I'm a man of science.

Offline Borek

  • Mr. pH
  • Administrator
  • Deity Member
  • *
  • Posts: 27820
  • Mole Snacks: +1808/-412
  • Gender: Male
  • I am known to be occasionally wrong.
    • Chembuddy
Re: Bronsted-Lowry acid/base theory question
« Reply #4 on: April 27, 2009, 03:57:03 AM »
How do you give a proton? Isn't a proton locked in the nucleus and electrons are the only particle that can travel from one atom to another?

Take a closer look at ionized hydrogen, one that is marked as H+.
ChemBuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info

Offline s3a

  • Regular Member
  • ***
  • Posts: 63
  • Mole Snacks: +0/-0
Re: Bronsted-Lowry acid/base theory question
« Reply #5 on: April 27, 2009, 02:06:55 PM »
After reading wikipedia (http://en.wikipedia.org/wiki/Bronsted-Lowry), I found this: "acid + base is in equilibrium with conjugate base + conjugate acid." Is this ALWAYS true?

Is the first chemical always the acid then the base followed by the conjugate base and then the conjugate acid?

Thanks!

Offline sjb

  • Global Moderator
  • Sr. Member
  • ***
  • Posts: 3653
  • Mole Snacks: +222/-42
  • Gender: Male
Re: Bronsted-Lowry acid/base theory question
« Reply #6 on: April 27, 2009, 02:26:52 PM »
I wouldn't want to rely on the order of reactants telling me how they perform, after all 11 + 5 = 5 + 11, for instance

Offline Borek

  • Mr. pH
  • Administrator
  • Deity Member
  • *
  • Posts: 27820
  • Mole Snacks: +1808/-412
  • Gender: Male
  • I am known to be occasionally wrong.
    • Chembuddy
Re: Bronsted-Lowry acid/base theory question
« Reply #7 on: April 27, 2009, 02:57:07 PM »
"acid + base is in equilibrium with conjugate base + conjugate acid." Is this ALWAYS true?

Yes.

Quote
Is the first chemical always the acid then the base followed by the conjugate base and then the conjugate acid?

No.

HA <-> H+ + A-

HA is a conjugate acid of A-, A- is a conjugate base of HA.
ChemBuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info

Sponsored Links