Acids, bases and buffers

Question 1

Lewis acid

Answer 1

electron pair acceptor

Question 2

Lewis base

Answer 2

electron pair donor

Question 3

Bronsted Lowry base

Answer 3

proton acceptor

Question 4

Bronsted-Lowry acid

Answer 4

proton donor

Question 5

Dibasic acid

Answer 5

can form 2 conjugate bases

Question 6

Conjugate acid base

Answer 6

HA + B -> HB+ + A-
acid + base
Conjugate acid + conjugate base

Question 7

tribasic acid

Answer 7

can form 3 conjugate bases

Question 8

Strong acid

Answer 8

completely dissociate in aqueous solutions to produce H+ ions

large Ka
smaller pKa

Question 9

Weak acid

Answer 9

partially dissociate in aqueous solutions to produce H+ ions

small Ka
larger pKa

Question 10

Acid dissociation constant

Answer 10

ka = [H+][A-] / [HA] = [H+]^2/[HA]

Question 11

pH

Answer 11

-log10[H+]

measure of hydrogen ion concentration in solution

Question 12

[H+] from pH

Answer 12

10^-pH

Question 13

[H+] from acid dissociation constant

Answer 13

√(ka x [HA])

Question 14

pKa

Answer 14

-log10Ka

Question 15

Ionic product of water formula

Answer 15

Kw = [OH-][H+] = 1 x 10^-14

Question 16

Buffer solution

Answer 16

1. solution that resists change in pH
2. when small quantity of acid or alkali is added

Question 17

Ka of buffer solution

Answer 17

[salt] x [H+] / [HA]

Question 18

Concentrations after dilution

Answer 18

(intital volume/total volume) x conc

Question 19

End point

Answer 19

point where pH changes rapidly

Question 20

Equivalence point

Answer 20

point where enough acid has been added to react completely with all the base

Question 21

Larger Ka, smaller pKa

Answer 21

1. stronger acid
2. dissociates more readily in solution
3. equilibrium lies more to the right

Question 22

Limitations of Ka for stronger weak acids

Answer 22

1. [HA] equilibirum ~ [HA] undissociated
2. [HA] is bigger than [H+]
3. Negligible dissociation of H2O

Question 23

Buffer explanation

Answer 23

1. weak acid and soluble salt of weak acid
2. H+ added, conjugate base reacts, equilibrium shift to the left
   3.OH- added, H+ bond, equilibrium shifts to the right

Question 24

Carbonic acid hydrogencarbonate

Answer 24

CO2(g) +H2O(l) ⇌ H2CO3(aq) ⇌ H+(aq) +HCO3-(aq)

1. maintains blood pH 7.4
2. H+ shifts both equilibrium to the left
3. OH- shifts equilibrium to the right

Question 25

Phenopthalein

Answer 25

base - colourless acid- pink pH change 9 kln 10^-9

Question 26

Methyl orange

Answer 26

base - orange acid- yellow pH change 4 kln 10^-4

Question 27

Equilibrium shift of indicators

Answer 27

kln = [H+][ln-] / [Hln] Halfway point [ln-] = [Hln]

Question 28

Draw strong base, strong acid

Question 29

Draw strong base, weak acid

Question 30

Draw weak base, weak acid

Question 31

Draw weak base, strong acid