4.4.1: Acids, Bases and Kw

Question 1

Bronsted-lowry acids

Answer 1

proton donors, release H+ when mixed with water

Question 2

Bronsted-lowry bases

Answer 2

proton acceptors, take hydrogen ions from water molecules when in solution

Question 3

H+ ions are never by themselves in water, what are they part of instead?

Answer 3

combine with H2O

to form H3O+ (hydroxonium ions)

Question 4

General acid equation in water

Answer 4

HA + H2O -> H3O+ + A-

Question 5

General base equation in water

Answer 5

B + H2O -> BH+ + OH-

Question 6

Dissociate in water

Answer 6

break up into positive and negative ions

Question 7

What does the amount of dissociation depend on

Answer 7

how weak or strong the acid or base is

Question 8

Strong acid dissociation/ionisation

eqm position

Answer 8

almost completely in water,
nearly all H+ ions released,
eqm well to the right

Question 9

Dissociate aka

Answer 9

ionise

Question 10

Strong bases dissociation/ionisation

eqm position

Answer 10

almost completely in water,

eqm well to the right

Question 11

Weak acids dissociation/ionisation

eqm position

Answer 11

only very slightly in water,
so only small numbers of H+ ions are formed
eqm lies well to the left

Question 12

Weak bases dissociation/ionisation

eqm position

Answer 12

only slightly dissociate in water,

eqm lies well to the left

Question 13

Acids only get rid of protons if…

Answer 13

there is a base to accept them

Question 14

General acid-base reaction equation

Answer 14

HA + B BH+ + A-

Question 15

Water dissociation equation

and simplified equation

Answer 15

H2O + H2O H3O- + OH-

H2O H+ + OH-

Question 16

Water dissociated into

Answer 16

hydroxonium ions and hydroxide ions

H3O+ and OH-

Question 17

How much does water dissociate

eqm position

Answer 17

only a tiny amount,

eqm well to the left

Question 18

Concentration of water

and why

Answer 18

constant value

there is so much water compared to H+ and OH-

Question 19

Ionic product of water

Answer 19

Kw

Question 20

Kw expression

Answer 20

Kw = [H+] [OH-]

Question 21

The value of Kw for an aqueous solution at a given temperature

Answer 21

the same

Question 22

The value of Kw for an aqueous solution at 298K

Answer 22

1.00 x 10-14 mol2dm-6

Question 23

The value of Kw changes as the…

Answer 23

temperature changes

Question 24

In pure water [H+] …

Answer 24

[H+] = [OH-]

Question 25

Expression for pure water Kw

Answer 25

Kw = [H+]2