3.1.12 - acids and bases

Question 1

bronsted - lowry acid

Answer 1

proton donor

Question 2

bronsted - lowry base

Answer 2

proton accepter

Question 3

definition of pH

Answer 3

-log [H+]

Question 4

reverse of the pH equation

Answer 4

H+ = 10 ^ -pH

Question 5

what does amphoteric mean

Answer 5

a molecule that acts as an acid or base

Question 6

what is a monoprotic acid

Answer 6

an acid with one hydrogen

Question 7

what is a diprotic acid

Answer 7

an acid with two hydrogens

Question 8

definition of a strong acid

Answer 8

acids which dissociate completely

Question 9

definition of a weak acid

Answer 9

acids which only partially dissociate

Question 10

how do you work out [H+] of a monoprotic or diprotic acid

Answer 10

monoprotic concentration = [H+]
diprotic concentration X 2 = [H+]

Question 11

equation for Kw

Answer 11

[H+] [OH-]

Question 12

effect on temp on the pH of water

Answer 12

pH decreases, Kw increases as equilibrium moves right to oppose the change

Question 13

what is an indicator

Answer 13

a weak acid

Question 14

methyl orange

Answer 14

works at pH 3.2- 4.4
red in acid
orange at midpoint
yellow in alkali

Question 15

phenolphthalein

Answer 15

works at pH 8.2-10
colourless in acid
pink in alkali

Question 16

equilibrium of pH

Answer 16

low pH - equilibrium shifts to the left, more acid than base
high pH - equilibrium shifts to the right, more base than acid

Question 17

rules when choosing an indicator

Answer 17

sharp colour change
end point = equivalence point
distinct colour change

Question 18

which indicator is used for which pH curve

Answer 18

strong acid + strong base = phenolphthalein
strong acid + weak base = methyl orange
weak acid + strong base = phenolphthalein
weak acid + weak base = no indicator

Question 19

equivalence + steep pH values of SA + SB

Answer 19

E = 7
pH 3-9

Question 20

equivalence + steep pH values of SA + WB

Answer 20

E = < 7
pH 4-7

Question 21

equivalence + steep pH values of WA + SB

Answer 21

E = > 7
pH 7-9

Question 22

what is a buffer solution

Answer 22

solution that resists change in pH when small amounts of acid/alkali are added

Question 23

what are acidic buffers made from

Answer 23

a weak acid and a soluble salt of the acid.
excess of a weak acid and a strong alkali

Question 24

what are basic buffers made from

Answer 24

weak base and a soluble salt of the weak base.
excess of a weak alkali and a strong acid

Question 25

how do you find Ka

Answer 25

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