buffers
Moderators: Chem_Mod, Chem_Admin
-
- Posts: 80
- Joined: Fri Sep 28, 2018 12:18 am
buffers
Can someone explain to me what a buffer is? It seems to be something that makes the pH of the solution less likely to change, but how does it work on a molecular level?
-
- Posts: 115
- Joined: Fri Sep 24, 2021 6:38 am
Re: buffers
A buffer is when a weak acid/conjugate base or weak base/conjugate acid are in a solution together. This results in the ph minimally changing even when a strong base/acid is added to the solution and thus there has to be a set amount of strong acid/base necessary in order to change the ph.
-
- Posts: 51
- Joined: Mon Jan 03, 2022 10:36 am
Re: buffers
A buffer can resist pH change when small amounts of acid or base are added to the solution by neutralizing the added component
-
- Posts: 107
- Joined: Fri Sep 24, 2021 6:05 am
Re: buffers
A buffer is a substance that is dissolved into solution with the goal of preventing the solution from changing pH too drastically. Buffers are really important in biological systems. Buffers contain a conjugate acid/base that neutralizes whatever acid/base was added. For example, o=buffers play an important role in maintaining the pH of our blood. If our blood pH was any higher or lower, it would be lethal.
-
- Posts: 53
- Joined: Tue Feb 02, 2021 12:16 am
Re: buffers
Buffers are able to resist changes in pH because, as other students have mentioned, they contain a weak acid and its conjugate base (the conjugate base is typically in the form of a salt), or they contain a weak base and its conjugate acid (again, the conjugate acid is in the form of a salt).
To understand how this works, let's say a buffer solution was made of a weak acid and its conjugate base, in which we added the conjugate base as a salt. The weak acid will dissociate slightly, therefore donating H3O+ to the solution. These H3O+ ions in solution are able to neutralize a base if one is added, and thus allow the buffer to resist changes in pH when a base is added. On the other hand, there is also the salt present in the buffer solution. Because the buffer is an aqueous solution, the salt dissolves into a spectator ion and the weak acid's conjugate base. Thus, the salt adds more conjugate base to the buffer solution. This is important because the conjugate base is what will neutralize an acid if one is added to the buffer solution, as the conjugate base is able to accept the H3O+ ions from acids, and therefore allows the buffer resist changes in pH when an acid is added.
As another student said, there is a limit to the amount of acid/base we can add to a buffer before it no longer resists changes in pH. Once either all the H3O+ ions or the all of the conjugate base is reacted, then the buffer will not be so resistant to changes in pH.
To understand how this works, let's say a buffer solution was made of a weak acid and its conjugate base, in which we added the conjugate base as a salt. The weak acid will dissociate slightly, therefore donating H3O+ to the solution. These H3O+ ions in solution are able to neutralize a base if one is added, and thus allow the buffer to resist changes in pH when a base is added. On the other hand, there is also the salt present in the buffer solution. Because the buffer is an aqueous solution, the salt dissolves into a spectator ion and the weak acid's conjugate base. Thus, the salt adds more conjugate base to the buffer solution. This is important because the conjugate base is what will neutralize an acid if one is added to the buffer solution, as the conjugate base is able to accept the H3O+ ions from acids, and therefore allows the buffer resist changes in pH when an acid is added.
As another student said, there is a limit to the amount of acid/base we can add to a buffer before it no longer resists changes in pH. Once either all the H3O+ ions or the all of the conjugate base is reacted, then the buffer will not be so resistant to changes in pH.
-
- Posts: 101
- Joined: Fri Sep 24, 2021 6:24 am
Re: buffers
People have had great responses, but for simplicity's sake, I wanted to add that in Friday's lecture Dr. Levelle described a buffer as being both a "source" and a "sink" for protons, no matter what species (acidic or alkaline) is added to the solution.
Return to “Identifying Acidic & Basic Salts”
Who is online
Users browsing this forum: No registered users and 3 guests