Acids+ Bases

Question 1

Brønsted-Lowry acid

Answer 1

Proton donor

Question 2

Brønsted-Lowry base

Answer 2

Proton acceptor

Question 3

Neutralisation of an acid by an alkali

Answer 3

H3O+(aq) + OH-(aq) -> 2H2O(l)

H+(aq) + OH-(aq) -> H2O(l)

Question 4

Monobasic acid

Answer 4

1 hydrogen ion can be replaced per molecule e.g. HCl

Question 5

Dibasic acid

Answer 5

2 hydrogen ions can be replaced per molecule e.g. H2CO3

Question 6

Tribasic acid

Answer 6

3 hydrogen ions can be replaced per molecule e.g. H3BO3

Question 7

Redox reactions between acids and metals

Answer 7

Acid + metal -> salt + hydrogen

Question 8

Neutralisation with carbonates

Answer 8

Acid + carbonate -> salt + water + carbon dioxide

Question 9

Neutralisation with metal oxides

Answer 9

Acid + base -> salt +water

Question 10

Neutralisation with alkalis

Answer 10

Acid + alkali -> salt + water

Question 11

pH < 7

Answer 11

Acidic (red)

Question 12

pH = 7

Answer 12

Neutral (green)

Question 13

pH > 7

Answer 13

Alkaline (blue)

Question 14

Low value of [H+]

Answer 14

High pH

Question 15

High value of [H+]

Answer 15

Low pH

Question 16

pH calculation

Answer 16

-log [H+(aq)]

Question 17

Calculation for [H+] (strong acids)

Answer 17

10 ^-pH

Question 18

Strong acid

Answer 18

Completely dissociates in aqueous solution

Question 19

Weak acid

Answer 19

Only partially dissociates in aqueous solution

Question 20

What is Ka

Answer 20

Acid dissociation constant

Question 21

Ka calculation

Answer 21

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

Question 22

When does Ka change

Answer 22

With temperature (standard = 25degrees)

Question 23

pKa in terms of Ka

Answer 23

pKa = - log Ka

Question 24

Ka in terms of pKa

Answer 24

Ka =10^-pKa

Question 25

Stronger acid Ka and pKa

Answer 25

Larger Ka and smaller pKa

Question 26

Weak acid Ka and pKa

Answer 26

Smaller Ka and larger pKa

Question 27

Weak acid Ka calculation

Answer 27

[H+(aq)]^2/ [HA(aq)]

Question 28

2 assumptions when calculation pH of weak acids

Answer 28

1) neglect H+ ions from dissociation of water [H+]eqm = [A-]eqm 2) [HA]eqm = [HA]initial

Question 29

pH of weak acid calculation

Answer 29

[H+(aq)] = root (Ka x [HA(aq)] pH= -log[H+]

Question 30

Determining Ka experimentally

Answer 30

- prepare standard solution of weak acid of known concentration - measure the pH of the standard solution using a pH meter

Question 31

Justifying weak acid assumptions

Answer 31

1) at 25degrees [H+] from dissociation of water = 10^-7. pH>6 = significant [H+] 2) not justified for stronger weak acids with Ka>10^-2 moldm^-3

Question 32

Kw

Answer 32

``` Ionic product of water -ions in water multiplied - [H+] [OH-] -1 x 10^-14 = [H+]^2 ```

Question 33

[H+(aq)] > [OH-(aq)]

Answer 33

acidic solution

Question 34

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

Answer 34

Neutral solution

Question 35

[H+(aq)] < [OH-(aq)]

Answer 35

Alkaline solution

Question 36

pH calculation for strong bases

Answer 36

[H+] = Kw/[OH-] pH= -log[H+]

Question 37

[H+] for pH x

Answer 37

10^-x moldm^-3

Question 38

[OH-] for pH x

Answer 38

10^-14-x moldm^-3