acids + bases

Question 1

Ka =

Answer 1

[H+] [A-] / [HA]

Question 2

Kc =

Answer 2

[products] / [reactants]

Question 3

Gibbs free energy (Δ G) =

Answer 3

= Δ H − T Δ S

Question 4

pH =

Answer 4

-log[H+]

Question 5

[H+] =

Answer 5

10 -pH

Question 6

ionic product of water (KW) at 298K

Answer 6

1x10-14 mol2dm-6

Question 7

why is [H+] larger at higher temps (for water)

Answer 7

because temp increase favours endothermic reaction, shifting equilibrium to right ∴ KW increases ∴ [H+] increases

Question 8

how can you tell if something is a catalyst

Answer 8

it is expressed in the rate equation but not in the stoichiometric equation

Question 9

assumptions made about weak acids (2)

Answer 9

1) [HA] at equ. ≈ [HA] initial

2) [A-] ≈ [H+] because [H+] from water is negligable

Question 10

eq. ionic product of water (Kw)

Answer 10

[H+][OH-]

Question 11

eq. pH of water

Answer 11

[H+] = √Kw

Question 12

eq. pH of diluted strong acid

Answer 12

[H+] x (old vol / new vol) —> -log(ans)

Question 13

effect of temperature on pH of water

Answer 13

temp increase = equilibrium shift to the right
[H+] and [OH-] INCREASE
Kw increase, pH decrease

Question 14

effect of temp on neutrality of water

Answer 14

no effect, as [H+] = {OH-] still

Question 15

eq. for calculating pH of a strong base

Answer 15

[H+] = Kw/ [OH-]

Question 16

eq. Ka of weak acids in aqueous solution with nothing else added

Answer 16

Ka = [H+]² / [HA]

Question 17

bronsted-lowrey acid

Answer 17

a proton donor

Question 18

bronsted-lowrey base

Answer 18

a proton acceptor

Question 19

monobasic acid

and eg.

Answer 19

an acid that releases 1 H+ ion per molecule

eg. = HCl

Question 20

dibasic acid

and eg.

Answer 20

an acid which releases 2 H+ ions per molecules

eg. H2SO4

Question 21

acid + metal =

Answer 21

salt and hydrogen

Question 22

acid + carbonate =

Answer 22

salt + water + CO2

Question 23

acid + base =

Answer 23

salt + water

Question 24

conjugate acid-base pair

Answer 24

2 species which can be converted Ito each other by the transfer of a proton

Question 25

2 ways of making an acidic buffer

Answer 25

1) weak acid and one of its salts | 2) mix of excess weak acid and strong base

Question 26

2 ways of making an basic buffer

Answer 26

1) weak base and one of its salts | 2) mixture of an excess of weak base and strong

Question 27

pH blood plasma has to be

Answer 27

7.35-7.45

Question 28

buffer system in the body

Answer 28

carbonic acid-hydrogen carbonate

Question 29

equilibrium for body buffer system

Answer 29

H2CO3 ⇌ H+ + HCO3

Question 30

what happens to body equilibrium when H+ added

Answer 30

[H+] increases [H+] reacts with conjugate base HCO3- eq. moves left, making more H2CO3, removing H+

Question 31

what happens to body equilibrium when OH- added

Answer 31

[OH-] increases small conc go H+ react w OH- H2CO3 dissociates to restore H+ ions eq. shifts right, making more HCO3- and H+

Question 32

how does body prevent build up of H2CO3

Answer 32

converts it to CO2 which is exhaled by lungs

Question 33

weak acid

Answer 33

do not fully dissociate

Question 34

derivatives of carboxylic acid (4)

Answer 34

- ester - acyl chloride - acid anhydride - amide

Question 35

methyl orange can always be used with....

Answer 35

strong acid

Question 36

phenolphalien can always be used with...

Answer 36

strong base

Question 37

pH weak acid

Answer 37

[H+] = √ KA x [HA]

Question 38

d. indicator

Answer 38

weak acids which have a different colour to their conjugate base

Question 39

relationship between PKa and Ka

Answer 39

PKa = -log(Ka)

Question 40

equation for: pH of mixture when H+ is in excess | weak acid

Answer 40

= H+ = Ka x [HA]/[A-]

Question 41

equation for: pH of mixture when OH- is in excess

Answer 41

H+ = KW/[OH-]

Question 42

equation for: pH of mixture when H+ is in excess | strong acid

Answer 42

pH = -log(H+)

Question 43

acid + metal ->

Answer 43

salt + hydrogen

Question 44

acid + carbonate ->

Answer 44

salt + CO2 + H2O

Question 45

acid + base ->

Answer 45

salt + water

Question 46

acid + alkali ->

Answer 46

salt + water

Question 47

the bigger the value of Ka the further the eq is to the....

Answer 47

RIGHT

Question 48

stronger acids have ...

Answer 48

larger Ka , smaller pKA

Question 49

what is pKa used for?

Answer 49

comparing

Question 50

equivalence point

Answer 50

the point in a titration where a volume of one solution has reacted exactly with a volume of the other

Question 51

end point of titration

Answer 51

indicator contains equal vols of HA and A-