CGIER 38 - The importance of pH in biological functions

Question 1

where are acid base groups found and name an example of each

Answer 1

NH2 COOH

found in macromolecules and smaller molecules

Question 2

pH of blood

Answer 2

7.35-7.45
pH too low - acidosis
pH too high - alkylosis

Question 3

Arrhenius definition of acid

Answer 3

ionise in water to give H+

Question 4

Arrhenius definition of base

Answer 4

ionise in water to give OH-

Question 5

Lewis base

Answer 5

donate a pair of electrons

Question 6

lewis acid

Answer 6

accept a pair of electrnos

Question 7

Bronsted Lowry definition of acid

Answer 7

H+ donor

Question 8

Bronsted Lowry definition of base

Answer 8

H+ acceptor

Question 9

How is pH of blood maintained

Answer 9

by buffer systems - chemical equilibria that can resist serious changes in pH upon addition of acids or bases (chemical acid-base equilibrium system that shifts left or right depending on how much acid or base is added - uses lewis definition)

Question 10

amphoteric

Answer 10

depending on where it finds itself it can act as an acid or base e.g. H2O
in the presence of an acid it acts as a base and vice versa

Question 11

weak acid examples

Answer 11

weak acid =/= diluted strong acid
HF
HCN
HNO2
HCOOH
CH3COOH

Question 12

Strong bases

Answer 12

NaOH
KOH
Ba(OH)2
Li(OH)

Question 13

weak bases

Answer 13

NH3, CH3NH2, C6H5NH2

Question 14

strong acids

Answer 14

HClO4 > HI > HBr > HCl > H2SO4 > HNO3

Question 15

arrhenius definition of weak acid

Answer 15

will ionise partially

Question 16

arrhenius definition of weak base

Answer 16

will ionise partially

Question 17

if an acid is strong the conjugate base must be

Answer 17

weak

Question 18

if the base is strong the conjugate acid is

Answer 18

weak

Question 19

dissociation constant with weak acid/base

Answer 19

keep the weak base as the denominator for the equilibrium but remove the acid
for acid keep the weak acid but remove the base

Question 20

pure water conducts…

Answer 20

Pure water conducts electricity (slightly) due to autodissociation

Question 21

anything above 7 is ..

Answer 21

alkaline

Question 22

anything below 7 is..

Answer 22

acidic

Question 23

Kw

Answer 23

dissociation of water

[H30+][OH-]

Question 24

Ka

Answer 24

[H30+][A-] / [HA]

Question 25

Kb

Answer 25

[HA][OH-] / [A-]

Question 26

Ka in terms of Kw and Kb

Answer 26

Kw/Kb

Question 27

Kb in terms of Ka and Kw

Answer 27

Kw/Ka

Question 28

Kw in terms of Ka and Kb

Answer 28

Ka x Kb

Question 29

pH for acid and pOH for base

Answer 29

𝐩𝐇=−𝐥𝐨𝐠𝟏𝟎[𝐇+]

𝐩𝐎𝐇=−𝐥𝐨𝐠𝟏𝟎[𝐎𝐇]

Question 30

pH + pOH =

Answer 30

14

Question 31

Who introduced the concept of pH

Answer 31

Arnold Beckman,

Question 32

pH of saliva

Answer 32

6.5-7.5

Question 33

pH of upper stomach

Answer 33

4-6.5

Question 34

pH of lower stomach

Answer 34

1.5-4.0

Question 35

pH of Duodenum

Answer 35

7-8.5

Question 36

pH of small intestine and large intestine

Answer 36

4-7