chem 106 test 3

Question 1

acid characteristics

Answer 1

H+, low pH, sour, litmus turns red

Question 2

base characteristics

Answer 2

OH-, high pH, bitter, turn litmus blue

Question 3

strong acids

Answer 3

HCl, HBr, HI, H2SO4, HNO3

Question 4

strong bases

Answer 4

alkali metals + hydroxide (e.g., NaOH, KOH)

Question 5

opposite of strong is

Answer 5

negligible

Question 6

opposite of weak is

Answer 6

weak

Question 7

opposite of negligible is

Answer 7

strong

Question 8

Ka > 1

Answer 8

strong acid

Question 9

Ka < 1

Answer 9

weak acid

Question 10

higher Ka means

Answer 10

stronger acid

Question 11

Kw =

Answer 11

[H3O+][OH-] = 1.0 x 10^-14

Question 12

significant figures inside the log yields # ? outside of the log

Answer 12

decimal places
(e.g., -log(1.0x10^-12)=12.00
2 SF => 2 decimal places)

Question 13

Ka =

Answer 13

[H3O+][A-] / [HA]

Question 14

% ionization

Answer 14

change / initial

Question 15

you can assume x is negligible if

Answer 15

x < 5% of the initial (Ka really small means x is probably really small)

Question 16

anions

Answer 16

conjugate bases of some acid (weak acid => weak base, strong acid => negligible base)

Question 17

cations

Answer 17

if they contain H+’s, they may be acidic

Question 18

cations from weak bases + CB strong acid will affect pH in this way:

Answer 18

lower (NH4Cl)

Question 19

cations from strong bases + CB strong acid will affect pH in this way:

Answer 19

no change (NaCl)

Question 20

cations from weak bases + CB weak acid will affect pH in this way:

Answer 20

? must tell by Ka and Kb (NH4F)

Question 21

cations from strong bases + CB weak acid will affect pH in this way:

Answer 21

increase (NaF)

Question 22

polyprotic acids: if Ka1 > Ka2 by 10^3, ?

Answer 22

the second dissociation is negligible

Question 23

common ion effect

Answer 23

adding a strong acid to a weak acid solution will increase [H+] and shift equilibrium left

Question 24

buffers

Answer 24

solutions that resist change in pH (weak acid and its conjugate base - e.g., HOAc and OAc-)

Question 25

How to recalculate [HX] and [X-] after addition of strong acid

Answer 25

strong acid will use up [X-] to form more [HX], so subtract from the base and add to the acid

Question 26

How to recalculate [HX] and [X-] after addition of strong base

Answer 26

strong base will use up [HX] to form more [X-], so subtract from the acid and add to the base

Question 27

pH of blood

Answer 27

7.35-7.45

Question 28

3 factors that shift HbH+ + O2 HbO2 + H+ to the left

Answer 28

1. consumption of O2 in muscle
2. increase in body temp.
3. CO2 and lactic acid generated by metabolism

Question 29

titrations

Answer 29

known concentration of base is added to an acid of unknown concentration or strength to determine concentration or strength

Question 30

equivalence point

Answer 30

[acid] = [base]

Question 31

4 zones to graph titration curve

Answer 31

1. initial pH
2. before equivalence point
3. at equivalence point
4. after equivalence point

Question 32

how to calculate initial pH if acid is in the flask

Answer 32

pH = -log[strong acid]

Question 33

how to calculate pH before equivalence point if acid is in the flask

Answer 33

pH = -log[(mol acid - mol base) / (volume acid + volume base)]

Question 34

how to calculate pH at the equivalence point

Answer 34

pH = 7

Question 35

how to calculate pH after the equivalence point if acid began in the flask

Answer 35

pH = 14 - (-log[(mol base - mol acid) / (volume base + volume acid)])