Gen Chem II: Exam 3

Question 1

what happens at the eq. pt.?

Answer 1

moles of titrant equals moles of analyte

Question 2

when the indicator changes color

Answer 2

end point

Question 3

how are indicators chosen?

Answer 3

they must change color near the eq. pt. pH

Question 4

pH indicators are —

Answer 4

organic acids and dyes

Question 5

SB/SA the pH at the eq. pt. is —

Answer 5

7

Question 6

SA/SB before the eq. pt., pH is determined by —

Answer 6

excess acid

Question 7

SA/SB after the eq. pt., pH is determined by —

Answer 7

excess base

Question 8

WA/SB half eq. pt.

Answer 8

mid point

Question 9

the mid point is located where

Answer 9

in the buffer region

Question 10

WA/SB — equals — at the mid-point

Answer 10

pH, pKa

Question 11

WA/SB the pH at the equivalence point is — bc —

Answer 11

greater than 7, the reaction bt the conjugate base and water

Question 12

WA/SB before the titration begins, pH is determined by —

Answer 12

the weak acid and Ka

Question 13

WA/SB after the titration begins, but before the eq pt, you have a — and pH can be calculated by —

Answer 13

buffer, H-H equation

Question 14

WA/SB at the eq pt, pH is determined by the —

Answer 14

conjugate base and Kb

Question 15

WA/SB after the eq pt, pH is determined by —

Answer 15

excess added base

Question 16

WB/SA the pH at the eq pt is — bc of —

Answer 16

less than 7, reaction bt conjugate acid and water

Question 17

WB/SA before the titration begins, pH is determined by —

Answer 17

weak base and Kb

Question 18

WB/SA after the titration begins, but before the eq pt, you have a — and pH can be calculated by —

Answer 18

buffer, H-H equation (must convert to pKa)

Question 19

WB/SA at the eq pt, pH is determined by the —

Answer 19

conjugate acid and Ka

Question 20

WB/SA after the eq pt, pH is determined by —

Answer 20

excess added acid

Question 21

amino acids are —

Answer 21

polyprotic acids

Question 22

an amino acids contains a — and a — in the same molecule

Answer 22

weak acid and weak base

Question 23

how much of a salt can dissolve in a given amount of solvent at a given temp

Answer 23

solubility

Question 24

units of molar solubility

Answer 24

M

Question 25

for a slightly soluble ionic compound in water, equilibrium bt a – and —

Answer 25

solute and aqueous ions

Question 26

what happens when a common ion is added to an “insoluble” compound?

Answer 26

the equilibrium shifts to the left and the solubility decreases and a precipitate forms

Question 27

the additions of H3O+ will — the solubility of a salt that contains the anion of a weak acid (basic anions); the equilibrium will shift tot he —

Answer 27

increase, right

Question 28

when no more solid can dissolve

Answer 28

saturated

Question 29

when Q=K

Answer 29

the solution is saturated and no change will occur

Question 30

when Q > K

Answer 30

precipitate will form until the remaining solution is saturated

Question 31

when Q

Answer 31

precipitate will not form bc the solution is unsaturated

Question 32

used to separate a solution containing a mixture of ions

Answer 32

selective precipitation

Question 33

added to the solution until the Q of the more soluble compound is almost equal to its K

Answer 33

precipitating ion

Question 34

the — soluble compound precipitates to max amt

Answer 34

less

Question 35

the — soluble compound remains in solution

Answer 35

more

Question 36

need lone pair, NH3 is an example

Answer 36

ligand

Question 37

consist of a central metal ion (lewis acid) covalently bonded to 2 or more anions or molecules, called ligands

Answer 37

complex ion

Question 38

why are complex ions favorable?

Answer 38

enhances solubility of “insoluble” compounds

Question 39

complex ion formation is a

Answer 39

stepwise process (Kf= Kf1 x Kf2 x Kf3 x Kf4)

Question 40

reducing agent is —

Answer 40

oxidized

Question 41

when the oxidation number increases

Answer 41

oxidation

Question 42

when the oxidation number decreases

Answer 42

reduction

Question 43

oxidizing agent is —

Answer 43

reduced

Question 44

uses a spontaneous redox reaction to generate electrical energy

Answer 44

voltaic or galvanic cell

Question 45

uses electrical energy to drive a nonspontaneous reaction

Answer 45

electrolytic cell

Question 46

electrochemical cells

Answer 46

voltaic and electrolytic

Question 47

both electrochemical cells consist of –

Answer 47

two electrodes placed in an electrolytic solution

Question 48

the difference in electrical potential bt the anode and cathode is called: (3)

Answer 48

cell voltage, electromotive force, cell potential

Question 49

— will always lose mass

Answer 49

anode

Question 50

— will always gain mass

Answer 50

cathode

Question 51

the voltage associated with a reduction reaction at an electrode when all solutes are 1 M and all gases are at 1 atm

Answer 51

standard reduction potential (E)

Question 52

all half-cell potentials are measured relative to —

Answer 52

SHE- standard hydrogen electrode

Question 53

Ecell for spontaneous reactions

Answer 53

positive

Question 54

each half-reaction contains a — and a —

Answer 54

reducing agent and a oxidizing agent

Question 55

the — oxidizing and reducing agents react to spontaneously form the — ones

Answer 55

stronger, weaker

Question 56

a spontaneous redox reaction will occur between a — and —

Answer 56

oxidizing agent and any reducing agent that lies below it in the emf series

Question 57

known concentration

Answer 57

titrant

Question 58

unknown concentration

Answer 58

analyte

Question 59

k>1 favors —

Answer 59

products

Question 60

k

Answer 60

reactants

Question 61

extensive

Answer 61

favors products

Question 62

non extensive

Answer 62

favors reactants

Question 63

battery

Answer 63

voltaic cell

Question 64

recharger

Answer 64

electrolytic cell

Question 65

cations move to —

Answer 65

cathode

Question 66

anions move to —

Answer 66

anode

Question 67

Formation constant (complex ion formation)

Answer 67

Kf

Question 67

Formation constant

Answer 67

If

Question 68

Kf=

Answer 68

[products]/[reactants]