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Question 1

what is an alkali?

Answer 1

soluble base

Question 2

define a Bronsted- Lowry acid

Answer 2

proton donor

Question 3

define a Bronsted- Lowry base

Answer 3

proton acceptor

Question 4

conjugate acid- base pair

Answer 4

contains 2 species that can be interconverted by transfer of a proton

Question 5

monobasic acid definition

Answer 5

donates 1 proton

Question 6

dibasic acid definition

Answer 6

donates 2 protons

Question 7

tribasic acid definition

Answer 7

donates 3 protons

Question 8

acid + metal

Answer 8

salt + hydrogen

Question 9

acid + carbonate

Answer 9

salt + water + carbon dioxide

Question 10

acid + base

Answer 10

salt + water

Question 11

acid + alkali

Answer 11

salt + water

Question 12

define pH

Answer 12

pH=-log[H+(aq)]

Question 13

define [H+(aq)]

Answer 13

[H+]=10^-pH

Question 14

what is a strong acid?

Answer 14

fully dissociates in aqueous solution

Question 15

how can the pH of a strong acid be calculated?

Answer 15

directly from the concentration of the acid

Question 16

what is a weak acid?

Answer 16

partially dissociates in aqueous solution

Question 17

write the general form for the dissociating of any weak acid, HA

Answer 17

HA(aq) ⇄ H+(aq) + A-(aq)

Question 18

acid dissociation constant, Ka equation

Answer 18

Ka= [H+(aq)][A-(aq)]/[HA(aq)]

Question 19

what are the units for Ka?

Answer 19

moldm⁻³

Question 20

how are Ka and pKa linked?

Answer 20

pKa=-logKa

Question 21

write the general form for the dissociating of any weak acid, HA

Answer 21

HA(aq) ⇄ H+(aq) + A-(aq)

Question 22

the stronger the acid…

Answer 22

• larger the Ka value

- smaller the pKa value

Question 23

the weaker the acid…

Answer 23

• smaller the Ka value

- larger the pKa value

Question 24

the weaker the acid…

Answer 24

• smaller the Ka value

- larger the pKa value

Question 25

how do you calculate the [H+] of a weak acid?

Answer 25

[H+]= √(Ka X [HA(aq)])

pH=-log[H+]

Question 26

write a Ka equation for HA(aq) ⇄ H+(aq) + A-(aq)

Answer 26

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

Question 27

what is the simplified version of Ka expression

Answer 27

Ka= [H+]²/ [HA]

Question 28

how do you calculate the [H+] of a weak acid?

Answer 28

[H+]= √(Ka X [HA(aq)])

pH=-log[H+]

Question 29

what is Kw also called?

Answer 29

ionic product of water

Question 30

write the expression for Kw

Answer 30

Kw= [H+(aq)] [OH-(a)]

Question 31

[H+] equation for water

Answer 31

[H+]= √(Kw)

Question 32

what can pH of a strong base be calculated from?

Answer 32

• concentration of the base

- ionic product of water Kw

Question 33

what is the pH of a solution with [OH-]= 4.5X10⁻³ at 25℃?

Answer 33

calculate pOH from [OH-(aq)]
- pOH=-log[OH-(aq)]=-log(4.5X10⁻³)= 2.34
calculate pH using pH+pOH= 14
- pH=14=pOH
- pH=14-2.34=11.66

Question 34

[H+] equation for water

Answer 34

[H+]= √(Kw)

Question 35

what are the concentrations of H+ and OH- in a solution with a pH of 3.25 at 25℃?

Answer 35

find [H+(aq)]
[H+(aq)]= 10^-pH= 10^-3.25=5.62X10⁻⁴ moldm⁻³
calculate [OH-(aq)] from Kw and [H+(aq)]
Kw= [H+(aq)][OH-(aq)]=1X10⁻¹⁴
[OH-(aq)]= Kw/ [H+(aq]=1X10⁻¹⁴/ 5.62X10⁻⁴ = 1.78X10⁻¹¹

Question 36

what is the pH of a solution with [OH-]= 4.5X10⁻³ at 25℃?

Answer 36

calculate pOH from [OH-(aq)]
- pOH=-log[OH-(aq)]=-log(4.5X10⁻³)= 2.34
calculate pH using pH+pOH= 14
- pH=14=pOH
- pH=14-2.34=11.66

Question 37

the pH of 0.065 moldm⁻³ propanoic acid, CH₃CH₂COOH is 3.04.calculate Ka

Answer 37

find [H+(aq)]
[H+(aq)]=10^-pH=10^-3.04=9.12X10⁻⁴ moldm⁻³
calculate Ka from [H+(aq)] and [HA(aq)]
Ka= [H+][CH₃CH₂COO-]/[CH₃CH₂COOH]
Ka=[H+]²/[CH₃CH₂COOH]
Ka= (9.12X10⁻⁴)²/0.065= 1.28X10⁻⁵ moldm⁻³

Question 38

calculate the pH of 0.0245 moldm⁻³ ethanoic acid, CH₃COOH at 25℃, where Ka=1.7X10⁻⁵ moldm⁻³.

Answer 38

calculate [H+(aq)] from Ka and [HA(aq)]
Ka= [H+][CH₃COO-]/ [CH₃COOH]
Ka= [H+]²/ [CH₃COOH]
[H+(aq)]=√Ka X [CH₃COOH]= √(0.0245 X 1.7 X 10⁻⁵)
= 6.45X10⁻⁴ moldm⁻³ 
find pH
pH=-log[H+]=-log(6.45X10⁻⁴)= 3.19