acids and bases

Question 1

bases soluble in water

Answer 1

are alkalis

Question 2

zinc hydroxide

Answer 2

Zn(OH)2

Question 3

acid definition

Answer 3

any substance that adds H+ ions to water
-proton donor

Question 4

hydronium ions

Answer 4

hydrogen atoms attach to h2o molecule to form H30

Question 5

base definition

Answer 5

proton acceptor

Question 6

weak acids

Answer 6

only a few molecules dissaaociste into ions

Question 7

strong acids

Answer 7

molecules completely dissociate into ions

Question 8

strong base

Answer 8

fully dissociate

Question 9

weak bases

Answer 9

react with water to form equilibrium with h2o

Question 10

conjugate acid

Answer 10

base plus h+

Question 11

conjugate base

Answer 11

acid reacting with base and donating proton

Question 12

equation for concentration

Answer 12

moles of ion concentration/ volume of solution

Question 13

pH =

Answer 13

-log10(H+)

Question 14

increasing conc if acid

Answer 14

decreases pH value

Question 15

pH of strong acid

Answer 15

-log10(H+)

Question 16

conc of strong acid

Answer 16

(H+) = 10-pH

Question 17

moles with conc and volume

Answer 17

conc times volume

Question 18

acid solution + aqueous base when calculating new pH

Answer 18

find change in volume
-find change in (H+)

Question 19

Kc =

Answer 19

products over reactants

Question 20

Kw =

Answer 20

H+ times OH-
units mol 2 dm-6

Question 21

equation for dissociation of water

Answer 21

H2O – H+ + OH-

Question 22

Kw at room temp

Answer 22

1 times 10-14

Question 23

temperature effect on kW

Answer 23

decreases if H and OH decrease and if conc of H and OH increase it increases

Question 24

why does Kw change when temp increases

Answer 24

because equilibrium shifts to right so conc of H and OH produced increases so larger number brings value of Kw up and goes down if conc decreases
-position shifts to right because ionisation of water endothermic

Question 25

how to find conc of H+ ions in equation

Answer 25

-H and OH equals H squared -to find H conc you have to square root KW value

Question 26

why is pure water always neutral

Answer 26

hydrogen ions always equal to amount of hydroxide ions

Question 27

how to work out conc of OH or H when kW given and one other concentration given

Answer 27

Kw divided by other concentration

Question 28

what doesnt affect Kw value of pure water

Answer 28

conc of H and OH ions -addition of base to water -addition of acid to water pH

Question 29

finding pH of strong acid

Answer 29

-log10 H+

Question 30

finding pH of strong base

Answer 30

-first find the concentration of OH ions using dissociation equation -find conc of H+ of ions -use Kw to find it - rearrange equation of Kw -

Question 31

dissociation of NaOH

Answer 31

NaOH = Na+ + OH-

Question 32

calculating conc of strong base

Answer 32

use pH to find conc of H ions -10-ph -use Kw to find conc of OH ions -OH = Kw/ H+

Question 33

pH and group 2 hydroxides

Answer 33

times by 2 because 1-2 ratio

Question 34

solubility going down group 2

Answer 34

increases

Question 35

factors that affect pH of solution

Answer 35

amount of dissociation -solubility -concentration of H+ ions -temperature

Question 36

calculating what mass of molecule dissolved into water

Answer 36

-use pH to find conc of solution --logH+ -then OH= Kw/ H+ -rearrange to get moles= conc times volume -mass= moles times molar mass

Question 37

calculating final pH of two solutions

Answer 37

-find moles of both compounds -which one is in excess- calculate limiting compound leftover after reaction -find conc of limiting in final solution -use Kw to find conc of opposite ion in final solution -use conc to find pH

Question 38

whats a buffer

Answer 38

resists change in pH when small amounts of acid are added to it or base

Question 39

what must buffer solutions have

Answer 39

high concentrations of undissociated acids and high concs of its conjugate base

Question 40

exam question how does a buffer resist changes in pH upon addition of a small amount of acid

Answer 40

write down reversible reaction for specific buffer state that adding acid increases H+ state that equilibrium shifts to the left to lower the conc of H+ state that overall H+ remain almost constant

Question 41

exam question how does a buffer resist changes in pH upon addition of small amount of base

Answer 41

write down reversible reacrtion for specific buffer state that reacrion takes place between OH- and H+ which lowers the conc of H+ ions in buffer solution state that equilibrium shifts to right to replenish lost H+ state that overall H+ remains almost constant

Question 42

use of buffers in real life

Answer 42

brewing of beer blood- hydrogencarbonate swimming pools

Question 43

alkaline buffers

Answer 43

weak base and conjugate acid pH below 7