pH and Buffers

Question 1

example of weak acid

Answer 1

acetic acid

Question 2

Ka=

Answer 2

h+ x conjugate base/ weak acid

it tells us the degree of dissociation to determine if weak or strong acid

Question 3

pH=

Answer 3

-log (H+)

Question 4

pKa=

Answer 4

-log (Ka)

Question 5

henderson- hasselbalch equation

Answer 5

pH= pka+log(conjugate base conc./ acid conc.)

Question 6

define buffer

Answer 6

molecules that RESIST pH changes by the small additions of acid or base to a system

• usually mixture of weak acid/ its conjugate base
  OR weak base and its conjugate acid

Question 7

midpoint in titration tells us..

Answer 7

WHERE the buffer system buffers

- can extend 1pH unit either side of the pKa value

Question 8

what is the midpoint

Answer 8

point where pH=pKa

Question 9

when the conjugate base concentration is higher then this buffer is good at buffering….

Answer 9

added acid

Question 10

when the acid concentration is higher then this buffer is good at buffering…

Answer 10

added bases

Question 11

how is INTRA-cellular pH maintained at 7.4

Answer 11

phosphate and histidine side chain of proteins

Question 12

how is EXTRA-cellular pH maintained at 7.4

Answer 12

the BICARBONATE buffer system

Question 13

name the 3 buffer system is saliva

Answer 13

1. bicarbonate - most important in stimulated saliva
2. phosphate
3. proteins - histidine chains