Acid-base

Question 1

define base

Answer 1

proton/H+ acceptor

Question 2

define acid

Answer 2

proton/H+ donor

Question 3

define conjugate pairs

Answer 3

2 species related by the loss/gain of one H+ ion

Question 4

how to identify an acid-base conjugate pair

Answer 4

what accepts H+ from who in an equation

Question 5

define monobasic

Answer 5

species with one donatable H+

Question 6

define dibasic

Answer 6

has 2 donatable H+s

Question 7

define tribasic

Answer 7

species with 3 donatable H+s

Question 8

equation for pH using [H+]

Answer 8

pH = -log10[H+]

Question 9

how to find [H+] from pH

Answer 9

10^-pH

Question 10

equation for Kw of water

Answer 10

Kw = [H+][OH-] = 10^-4 mol2dm-6

Question 11

in the kW of water, why is the concentration of water (on the bottom of the equation) not used

Answer 11

it is such a large concentration that is hardly changes
: ignore it

Question 12

define neutrality for pure water

Answer 12

[H+] = [OH-]

Question 13

what happens to Kw of water when temperature increases

Answer 13

equilibrium shifts to RHS
as forwards reaction is endothermic
causing Kw to increase

Question 14

what happens to Ph of water when temperature increases

Answer 14

as Kw increases, using the equation
pH decreases

Question 15

even though pH of water changes with temp, why doesn’t neutrality

Answer 15

because [H+] = [OH-] still

Question 16

define strong acid

Answer 16

acid completely dissociates

Question 17

what does a strong acid dissociation equation look like

Answer 17

one way arrow because reaction is non-reversible

Question 18

give the list of strong acids

Answer 18

HCl
H2SO4 (only first H+)
HNO3
HClO4
(HBr)
(HI)

Question 19

define weak acid

Answer 19

acid partially dissociates

Question 20

what does a weak acid dissociation equation look like

Answer 20

double, reversible arrow because it is a reversible arrow

Question 21

give the list of weak acids

Answer 21

HF
any carboxylic acid
HCN
HClO
H3PO4
H2CO3

Question 22

equation for measuring weak acid dissociation

Answer 22

Ka = [H+] [A-] / [HA] moldm-3

Question 23

strong acid info

Answer 23

on ph calculations page

Question 24

what are the 2 assumptions when doing weak acid calculations

Answer 24

[H+] from H2O is negligible
CH6COOH dissociation is negligible

Question 25

define buffer

Answer 25

solution that resists changes in pH when a small amount of extra acid/base is added

Question 26

what are the 3 ways to make a buffer

Answer 26

adding acid (aq) + salt (s) adding acid (aq) + salt (aq) adding acid (aq) + alkali

Question 27

what do all methods of buffers result in

Answer 27

result in high salt conc and acid conc

Question 28

how do buffers work (general explanation using maths)

Answer 28

because [H=] = Ka x [HA]/[A-], the buffer depends on the salt to acid ratio

Question 29

how does a buffer solution work (mps)

Answer 29

1) [HA] and [ A-] are both large 2) when extra acid/base is added (extra acid = equilibrium shifts to LH extra base = equilibrium shifts to RHS) 3) RATIO [ha] : [A-] changes very little 4) [H+] changes very little 5) pH changes very little

Question 30

do indicator flashcards

Question 31

where can i read more about indicators and how they work

Answer 31

on the onenote

Question 32

how to work out the Pkin for indicators

Answer 32

Question 33

how does pH of blood increase with hyperventilating

Answer 33

hyperventilation [CO2] in blood decreases both equilibriums shift to LHS H+ conc decreases and pH increases again

Question 34

how to work out ph of strong acid

Answer 34

get new [H+] and work out pH from that

Question 35

how to work out the pH of a strong base

Answer 35

get new [OH-] use Ka to get [H+] use this to find pH

Question 36

how to work out pH of weak acid

Answer 36

buffer calculate new [ HA-] : [A-] use Ka then calculate new pH

Question 37

how to work out the pH of a weak base

Answer 37

you can't

Question 38

what ph's are the vertical region for strong acid + strong base and what is the ph at equivalence

Answer 38

between 3 and 11 ph at equivalence = 7

Question 39

what ph's are the vertical region for strong acid + weak base and the ph at equivalence

Answer 39

between 3 and 8 ph at equivalence 5.5

Question 39

what ph's are the vertical region for weak acid + strong base and the ph at equivalence

Answer 39

between 6 and 11 ph at equivalence = 8.5

Question 40

what ph's are the vertical region for weak acid + weak base and the ph at equivalence

Answer 40

between 6 and 8 ph at equivalence = not used as no indicator as indicator too small

Question 41

learn about half neutralisation in the ph curves section in OneNote

Question 42

what is the buffer region on a ph curve graph

Answer 42

the first flat bit

Question 43

draw a ph curve example with strong acid and strong base

Answer 43

Question 44

draw a ph curve for a half equivalence/half neutralisation graph

Answer 44

Question 45

why is a half neutralisation graph make sense

Answer 45