Buffers

Question 1

What is a buffer?

Answer 1

Aqueous systems that resist pH charge when small amount of acid or base are added, consist of a wear acid and its conjugate base

Question 2

Buffering power is maximized when …

Answer 2

amount of proton acceptor=amount of proton donor and pH=pKa, this happens at the midpoint of a titration curve

Question 3

Buffers result from two ______ reaction equilibrium occurring in a solution of nearly equal ______ _____ and ______ ______ concentrations. Whenever ___ or ____ is added the result is a small change in _____ ____ which leads to a ____ pH change.

Answer 3

reversible/proton donor/proton aceptor/H+/OH-/concentration ratio/small

Question 4

The small changes are cause by …

Answer 4

the decrease in concentration of one being blanked by the increase of the other so the sum change is nothing/very small

Question 5

Buffering region is ______ to each conjugate pair

Answer 5

specific

Question 6

Henderson-Hasselbach equation (for ionization of a weak acid) = ?

Answer 6

pH = pKa+log([A-]/[HA]) / pH = pKa-log([HA]/[A-])

• [A-] = weak/conjugate acid
• [HA] = weak/conjugate base

Question 7

What are some examples of buffer system uses biologically?

Answer 7

• maintaining intracellular pH

- maintaining in vivo pH

Question 8

What are in vivo buffer systems based/dependant on?

Answer 8

• phosphate, based on mM concentration
• bicarbonate (for blood plasma)
• histidine (efficient at pH~7.0)