Buffer System (1 Viewer)

DatAtarLyfe

Booty Connoisseur
Joined
Mar 10, 2015
Messages
1,805
Gender
Female
HSC
2016
Can someone explain to me how buffers work?
I know what they're purpose is and where they're used, but i can't actually understand HOW they manage to maintain that certain pH?

I've read the jacaranda textbook which just confused me, and read another set of notes that basically simplified it too much to the point were i couldn't even except it.

Can someone break it down for me?

Thanks
 

leehuan

Well-Known Member
Joined
May 31, 2014
Messages
5,805
Gender
Male
HSC
2015
Ok so buffers are really just an equilibrium system held in the body to maintain pH levels.

One of the most important buffers in the human body is the hydrogen carbonate ion buffer:

CO3(2-) + H2O ⇌ HCO3(-) + H3O(+) ⇌ CO2 + H2O

Effects such as acidosis only become prevalent when the buffer system breaks down. Before then, however

Note that your human body has a relatively even concentration of both the carbonate ion CO3(2-) and the hydrogen carbonate ion HCO3(-). Consider only the first two reactants and products. If the blood in the human body suddenly becomes more acidic, then according to LCP the equilibrium will shift to the left to reduce the amount of pH present. The HCO3(-) ion is then converted to the CO3(2-) ion, which isn't really basic when in low quantities, and effectively allows body pH to be regulated (by removing excess acid, H+).

By extension, the amount of CO2 in our body will also increase. LCP is able to predict that the equilibrium will shift ALL the way to the left

When we breathe out, our body eliminates CO2. To cater for the lost CO2 in the body, the equilibrium will shift to the right, and thus the excess CO3(2-) produced will then be eliminated.

[If the pH of the blood becomes alkaline, then this also shifts the equilibrium to the right to minimise such disturbances.]

Buffers are referred to as that because there exists roughly an equal concentration of HCO3(-) AND CO3(2-) in the system. Because both substances are present, it is quite obvious that dynamic equilibrium will eventually be achieved, but note that minute changes to the body's pH do not stir up the equilibrium greatly. It will take quite a significant amount of acid to start affecting a buffer system.

In essence, the buffer's role is to MINIMISE disturbances to the body naturally. There is a point where it breaks down, but the whole point of buffers is that it won't anytime soon.
 

BlueGas

Well-Known Member
Joined
Sep 20, 2014
Messages
2,448
Gender
Male
HSC
N/A
Basically an increase in one side of the equilibrium will result in an increase on the other side of the equilibrium.
 

DatAtarLyfe

Booty Connoisseur
Joined
Mar 10, 2015
Messages
1,805
Gender
Female
HSC
2016
So what does buffers have to do with conjugate acids and bases? The textbook seems to emphasise upon then a lot.
 

leehuan

Well-Known Member
Joined
May 31, 2014
Messages
5,805
Gender
Male
HSC
2015
So what does buffers have to do with conjugate acids and bases? The textbook seems to emphasise upon then a lot.
Apologies. I forgot to mention this.

Observe that the carbonate and hydrogen carbonate ion ARE conjugate B-L acids/bases.

CO3(2-) + H2O ⇌ HCO3(-) + H3O(+)

The reaction shows how the conjugate acid, to the carbonate ion base, is the hydrogen carbonate ion.

A buffer is specifically formed between a pair of conjugates. It is actually equivalent concentrations of BOTH in the conjugate pair.
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top