12. acid-base equilibria

Question 1

an acid

Answer 1

releases protons

Question 2

a base

Answer 2

accepts protons

Question 3

what are bronsted Lowry acid are

Answer 3

proton donors
release h ions when mixed with water

Question 4

what are bronsted Lowry bases are

Answer 4

proton acceptors
in solutions grab h ions from water molecules

Question 5

show equation of bronsted Lowry acids with water

Answer 5

HA + H2O arrow
H3O^+ + A^-

Question 6

show equation of bronsted Lowry bases with water

Answer 6

B + H2O arrow
BH^+ + OH^-

Question 7

strong acids

Answer 7

dissociate/ionise almost completely in water (nearly all h+ ions will be released)

example HCl

Question 8

strong bases

Answer 8

dissociate almost completely in water

example NaOH

Question 9

weak acids

Answer 9

dissociate slightly in water

example ethnoic acid

Question 10

weak bases

Answer 10

slightly protonate in water

example ammonia

Question 11

acid and base form

Answer 11

conjugate pairs

Question 12

conjugate pairs are

Answer 12

species that are linked by the transfer of a proton
always on opposite sides of the reaction equation

Question 13

conjugate base

Answer 13

species that has lost a proton

Question 14

conjugate acid

Answer 14

species that has gained a proton

Question 15

neutralization reaction is

Answer 15

when acid and bases react and form salt and water produced

Question 16

ph scale measures

Answer 16

the hydrogen ion concentration

Question 17

why do chemists use logarithmic scale to express ph

Answer 17

the conc of hydrogen ions can vary enormously

Question 18

PH =

Answer 18

-log[H^+]

Question 19

monoprotic

Answer 19

each mole of acid produces one mole of hydrogen ions

means H+ conc is the same as the acid conc

Question 20

polyprotic acids can

Answer 20

lose more than one proton

Question 21

monoprotic acids only

Answer 21

have one proton that they can release into solution

Question 22

each molecule of strong diprotic acid when dissociates

Answer 22

releases two protons

Question 23

what is ka

Answer 23

acid dissociation constant

Question 24

the ionic product of water kw depends on

Answer 24

concentration H^+ and OH^-

Question 25

water can act as

Answer 25

an acid and base by accepting and donating a proton

Question 26

kw =

Answer 26

[H^+][OH^-]

Question 27

units of kw

Answer 27

mol^2 dm^-6

Question 28

in pure water

Answer 28

there is a 1:1 ratio of H+ and OH- ions

Question 29

at 298 kelvins kw is

Answer 29

1.0 x 10^-14 mol^2 dm^-6

Question 30

pKw =

Answer 30

-log10kw kw = 10^-pkw

Question 31

under standard conditions kw is always

Answer 31

1.0 x 10^-14

Question 32

pka =

Answer 32

-log10ka ka= 10^-pka

Question 33

you can measure ph of a solution by using

Answer 33

a ph meter

Question 34

how to make sure ph meter is calibrated correctly

Answer 34

-place bulb of ph meter into deionised water and allow reading to settle -adjust reading so its 7.0 -do the same with a standard solution of ph 4 and another of ph 10 -make sure to rinse the probe with deionised water between each reading -now take the actual measurement

Question 35

euiqmolar substance

Answer 35

solutions that contain the same number of moles

Question 36

diluting an acid and how to affect ph

Answer 36

reduce the concentration of H^+ in the solution and increases ph

Question 37

diluting a strong acid by a factor of 10

Answer 37

increases ph by 1

Question 38

diluting a weak acid by a factor of 10

Answer 38

increases the ph by 0.5