Lecture 4: Acid-Base Chemistry

Question 1

organic acids are ___ acids

Answer 1

weak

Question 2

Buffers are solutions that

Answer 2

resist changes in pH

Question 3

human blood pH

Answer 3

7.35-7.45

Question 4

human pH above 7.4

Answer 4

alkalosis

Question 5

human pH below 7.35

Answer 5

acidosis

Question 6

what is associated with alkalosis

Answer 6

muscle spasms, convulsions

Question 7

what is associated with acidosis?

Answer 7

CNS depression, coma, death

Question 8

3 buffering systems in the body

Answer 8

1. bicarbonate
2. phosphate
3. protein

Question 9

buffers are often used in lab and are made my mixing appropriate concentrations of

Answer 9

weak acid and its conjugate base

Question 10

why can buffer resist pH change?

Answer 10

equilibrium between weak acid and conjugate base

Question 11

if more H atoms are added to a buffer, the equilibrium shifts towards formation of

Answer 11

acid

Question 12

if more OH ions are added to a buffer, the equilibrium shifts towards formation of

Answer 12

base

Question 13

le chatelier’s principle

Answer 13

when a stress is applied to a chemical system at equilibrium, it will shift to relieve the stresss

Question 14

why use a buffer in lab?

Answer 14

dont want reaction liquid to change pH as it may ruin or confound the experiment

Question 15

titration curve

Answer 15

plot of how the pH changes with amount of OH or H added

Question 16

the titration curve reveals the best buffering situation, which is where

Answer 16

a solution best resists change when acid/base is added

Question 17

the best buffering situation occurs when pH is equal to

Answer 17

pKa of acid

Question 18

when choosing a buffer in the lab, you should choose one that has a similar __ to that of your desired solution

Answer 18

pH

Question 19

the bicarbonate buffer is used to regulate ___. It involves ___ (ion) and ___ (molecule)

Answer 19

blood pH. Bicarbonate and CO2

Question 20

the amount of CO2 in blood is strictly controlled by the amount __-

Answer 20

lost while breathing

Question 21

the phosphate buffer is used to regulate

Answer 21

pH inside cells

Question 22

the protein buffer is used to regulate

Answer 22

amino acid buffering

Question 23

all amino acids have at least ___ ionizable groups

Answer 23

2

Question 24

all amino acids possess 5 components

Answer 24

1. alpha carbon
2. amino
3. carboxyl
4. hydrogen
5. r chain

Question 25

the amino and carboxyl group of an amino acid can be ionized based on surrounding

Answer 25

pH

Question 26

at typical cyto plasm pH, the amino will be ___ and the carboxyl will be ___

Answer 26

protonated; deprotonated

Question 27

amino acids are typically found in the ___ form

Answer 27

zwitter ion

Question 28

what is a zwitterion?

Answer 28

a molecule having separate positive and negative charged groups

Question 29

water ionizes to a very ___ degree

Answer 29

small

Question 30

pH (log scale) is used because

Answer 30

H concentrations can vary over a vast range

Question 31

pKa (log scale) is a measure of

Answer 31

the ability of weak acid to dissociate into H ions and CB

Question 32

pH influences ionization of many biomolecules and thus influences ___ of cell

Answer 32

chemical characteristics and chemistry