buffers (1 Viewer)

[annie_sinc]

Hey, could someone please help me with the specific example of a buffer in a natural system?

I've got some info on blood as a buffer, but i'm finding it really hard to understand it.

Does anyone hav an example of a different buffer in a natural system??

Or maybe someone could explain blood n i could try to understand :S

Thanks so much

 

[richz]

blood,

this is off the top of my head, havent really study chem much.

Ok a buffer is a substance which contains comparable amounts of a weak acid and its conjugate base. It is a substance that can maintain its pH even when large amounts of strong acid or base are added to it. Blood is an example
Hb +H3O+ <-> HHb+ + H2O (hopefully this eqn is rite)
When carbon dioxide is added to it the pH shud decrease but this doesnt not occur because it is a buffer.

 

[Casmira]

• Quantitatively describe the effect of buffers with reference to a specific example in a natural system
A buffer is a solution that resists rapid changes in pH when an acid or base is added, control of pH is crucial in living systems.

The components of a buffer system include mixing togther a weak acid and the salt of that acid, or weak base and the salt of that base, some buffers include;
- Acetic acid (CH3COOH) and sodium acetate (CH3COONa)
- Carbonic acid (H2CO3) and sodium bicarbonate (NaHCO3)

Blood is a buffered solution containing a range of pH buffers, one being carbonic acid, this allows ht epH to stay between 7.35pH – 7.45pH, the carbonic acid in our blood is weak that ionizes to form hydrogen carbonate ion.

 

[annie_sinc]

thanks heaps guys

 

[Abtari]

basically, any chemical system with comparable amounts of a weak acid and its conjugate base or a weak base and its conjugate acid is a buffer rite?

any such system where an equillibrium can be established is a buffer rite? cos when u add anything, then just according to le chatelier's principle, it shifts to the other side...and thats how resists change?

correct?

 

[rnitya_25]

basically, any chemical system with comparable amounts of a weak acid and its conjugate base or a weak base and its conjugate acid is a buffer rite?

any such system where an equillibrium can be established is a buffer rite? cos when u add anything, then just according to le chatelier's principle, it shifts to the other side...and thats how resists change?

correct?

yes you are correct.

if you want an example.......
if acid is added to the buffer HCO₃^-, H+ ions are removed by :
H⁺ + HCO3 ==> H₂CO₃
if a base is added to the buffer, hydroxide ions are removed by:
OH^- + HCO³ ==> H₂O + CO₃^2-

hope that makes sense

 

[Abtari]

so basically a buffer system is just an equilibrium system, only a special case (comparable amounts of weak acid and its conjugate base)

k then.thanks

 

[KFunk]

Blood is an example
Hb +H3O+ <-> HHb+ + H2O (hopefully this eqn is rite)
When carbon dioxide is added to it the pH shud decrease but this doesnt not occur because it is a buffer.

The one I know is:

HHb⁺ + 4O₂ <--> Hb(O₂)₄ + H⁺ where Hb represents haemoglobin

Then you have the

CO_{2 (aq)} + H₂O_(l) <-> H₂CO_{3 (aq)} <-> H⁺_(aq) + HCO^-_(aq)

Breathing in oxygen increases acidity and releasing carbon dioxide decreases acidity (which you can see looking at those equilibrium systems). If you get too much acid then you risk death by acidosis. Too little and you risk death by alkalosis.

 

[richz]

where did u get that from. i just got my one from conquering chem

 

[Abtari]

Breathing in oxygen increases acidity and releasing carbon dioxide decreases acidity (which you can see looking at those equilibrium systems). If you get too much acid then you risk death by acidosis. Too little and you risk death by alkalosis.

dont u mean breathing in carbon dioxide?

 

[Dreamerish*~]

dont u mean breathing in carbon dioxide?

I think so.

The haemoglobin system is also in CC.