1. Ionization of water, dissociation of weak acids, and buffers

Question 1

What are the two products from the ionization of water?

Answer 1

proton (H+)
hydroxide ion (OH-)

Question 2

What happens to hydrogen ions as water is ionized?

Answer 2

they hydrate to form hydronium ions

Question 3

How great of a chance does water have to ionize?

Answer 3

small

Question 4

What side of this equation does equilibrium lie?
H2O = H+ + OH-

Answer 4

left

Question 5

What is the Keq of the ionization of water?

Answer 5

low

Question 6

What happens to protons existing in a free solution?

Answer 6

hydrated to form hydronium ions (H3O+)

Question 7

Do free H+ ions ever exist in water?

Answer 7

no

Question 8

Why do protons hop?

Answer 8

hydronium ions are solvated by nearby water molecules, loosing the proton, which will create another hydronium ion and the process continues

Question 9

What is Kw?

Answer 9

ionic product of water

Question 10

What does the concentration of [H+] and [OH-] equal in pure water?

Answer 10

1*10^-7 M

Question 11

What does the pH scale designate?

Answer 11

the [H+] and [OH-] concentrations

Question 11

What is ‘p’ defined as?

Answer 11

the negative log of ‘something’

Question 11

What is the formula for pH?

Answer 11

-log[H+]

Question 12

What happens when you take the negative log of the Kw equation?

Answer 12

pH + pOH =14

Question 13

Is an acid or base a proton donor?

Answer 13

acid

Question 14

What does the expression ‘the pH scale is logarithmic’ mean?

Answer 14

change in 1 unit results in a 10 fold change

Question 15

What is a change in pH really a change of?

Answer 15

proton concentration

Question 16

Define alkaline

Answer 16

pH greater than 7

Question 17

Define acidic

Answer 17

pH less than 7

Question 18

What is the unit for ion concentration when calculating pH?

Answer 18

mols/L

Question 19

What will strong acids have a lot of?

Answer 19

protons able to be donated

Question 20

How do WEAK electrolytes interact with water?

Answer 20

only partially dissociate

Question 21

What does Ka measure?

Answer 21

the extent of acid dissociation

Question 22

What is a conjugate acid- base pair?

Answer 22

proton donor and its corresponding proton acceptor

Question 23

What does pKa measure?

Answer 23

acidity

Question 24

what is the equation of pKa?

Answer 24

-log(Ka)

Question 25

What is a titration curve?

Answer 25

a plot of pH against the amount of NaOH added

Question 26

What are buffers?

Answer 26

resist change in pH

Question 27

At what ratio is there a 50:50 mixture of acid and anion forms of the compounds?

Answer 27

pH = pKa

Question 28

What is the buffering zone?

Answer 28

1 pH below and above the midpoint

Question 29

Where is the buffering capacity greatest?

Answer 29

when pH = pKa

Question 30

What three things does the Henderson - Hasselbalch equation relate?

Answer 30

pH
pKa
buffer concentration

Question 31

What does the Henderson - Hasselbalch equation describe?

Answer 31

shape of the titration curve of any weak acid

Question 32

Why do cells use the buffer system?

Answer 32

to maintain intracellular pH levels

Question 33

What three weak acids are important for in vivo buffer systems?

Answer 33

phosphate
bicarbonate
histidine

Question 34

What two things does the bicarbonate buffer system depend on?

Answer 34

[HCO3-]
partial pressure of CO2