Exam 3

Question 1

Lewis acid

Answer 1

accepts a pair of electrons, compounds with less than an octet around the central atom can and metal ions act as lewis acids, negatively charged

Question 2

Lewis base

Answer 2

donates a pair of electrons

Question 3

coordinate bond

Answer 3

a covalent bond formed when one anion/molecule donates a pair of electrons to another ion/molecule

Question 4

ligand

Answer 4

a lewis base bonded to the central metal ion of a complex ion

Question 5

complex ion

Answer 5

ionic species consisting of a metal ion bonded to one or more lewis bases

Question 6

formation constant (Kf)

Answer 6

an equilibrium constant describing the formation of a metal complex from a free metal ion and its ligands

Question 7

Trend with acid strength and cation charge

Answer 7

direct

Question 8

Nonamphoteric hydroxides

Answer 8

1. Fe(OH)3
2. Fe(OH)2
3. Cu(OH)2

Question 9

Amphoteric hydroxides

Answer 9

1. Al(OH)3
2. Pb(OH)2
3. Sn(OH)2
4. Be(OH)2
5. Zn(OH)2
6. Cd(OH)2
7. Cr(OH)3

Question 10

how do common ions affect solubility?

Answer 10

common ions decrease solubility, but don’t affect the solubility product constant

Question 11

How do uncommon ions affect solubility?

Answer 11

the increase solubility

Question 12

when can you neglect s?

Answer 12

when it is <0.01

Question 13

Affect of pH on salt solubility

Answer 13

acidity increases the solubility of salts with basic anions due to shift in equilibrium reactions, weaker acids increases solubility more

Question 14

Q and Ksp relationship and effects

Answer 14

Q>Ksp, precipitate forms

Q

Question 15

reversible process formula

Answer 15

△S=qrev / T

Question 16

Second law of thermodynamics

Answer 16

Irreversible: △Suniverse=△Ssurroundings+△Ssystem>0

Reversible: △Suniverse=△Ssurroundings+△Ssystem> or = 0

Question 17

Standard molar entropy trends

Answer 17

Gases and molecules with the highest molar mass have the highest molar entropies. Entropy increases as the complexity of the molecular structure increases

Question 18

Which △G values indicate spontaneity in which direction?

Answer 18

△G<0: spontaneous in forward direction

△G>0: spontaneous in reverse direction

Question 19

△Grxn equation

Answer 19

△Grxn=△Gºrxn + RTln(Q)

Question 20

Relationship between △G◦ and K

Answer 20

indirect

Question 21

van’t hoff equation

Answer 21

ln(k1/k2)=△Hº/R(1/T2 - 1/T1)

Question 22

bolts,amm equation

Answer 22

s=kb x ln(w)

Question 23

Anode

Answer 23

electrode at which the oxidation half reaction takes place

Question 24

Cathode

Answer 24

electrode at which reduction half-reaction takes place

Question 25

△H and △S when a rxn is spontaneous at lower temperatures

Answer 25

both are negative

Question 26

△H and △S when aren is spontaneous at higher temperatures

Answer 26

both are positive

Question 27

△H and △S when a rxn is always spontaneous

Answer 27

negative △H and positive △S

Question 28

△H and △S when a rxn is never spontaneous

Answer 28

positive △H and negative △S

Question 29

Standard reductio potential

Answer 29

(Eºred), the voltage for a reduction reaction at an electrode when all solutes have activities=1 and gases=1 bar

Question 30

Standard oxidation potential

Answer 30

(Eºox) equal in magnitude but opposite in sign to Eºred

Question 31

Eºcell formulas

Answer 31

ºEcell=Eºred(cathode)-Eºred(anode)=Eºred(cathode)+Eºox(anode)

Question 32

What do standard reduction potentials tell you about their strengths as agents?

Answer 32

Higher positive value=stronger oxidizing agents and lower negative value = stronger reducing agents

Question 33

Spotaneity of reduction potentials

Answer 33

higher=more spontaneous | lower=nonspontaneous

Question 34

work formula

Answer 34

wmax=-QEcell=△G=nFEcell w=work in joules Q=total charge that passes through a cell

Question 35

what does emf stand for

Answer 35

electrical potential

Question 36

nernst equation forms with and without temperature

Answer 36

With T: Ecell=Eºcell - RT/nF ∙ lnQ Without T: Ecell=Eºcell - 0.0592/n ∙ logQ

Question 37

primary battery

Answer 37

cannot be recharged

Question 38

secondary battery

Answer 38

can be recharged

Question 39

Faraday law of electrolysis

Answer 39

m = aM/nF= aM/nF I t a/n= coefficients Q=charge I=current t=time

Question 40

Current variable and units

Answer 40

Variable: I Units: A

Question 41

corrosion

Answer 41

process in which metals react with oxidizing agents resulting in the formation of other compounds

Question 42

sacrificial anode

Answer 42

aka cathodic protection, a metal with a lower reduction potential making iron the the cathode

Question 43

ekectrolysis

Answer 43

process in which electrical energy causes a nonspontaneous reaction to occur. Oxidiation is at anode, reduction is at cathode, signs of electrodes are reversed, cathode is negative and anode is positive

Question 44

Where do cations and anions migrate to in battery cells?

Answer 44

cations to cathode, anions to anode

Question 45

How is the mass of each electrode affected in a battery?

Answer 45

Anode doesn’t always lose mass because of gases, cathode always gains mass

Question 46

Sigma bonds

Answer 46

1. end to end overlap of orbitals 2. s-s, s-p, or p-p orbitals 3. stronger 4. one symmetrical electron cloud symmetrical to internuclear axis

Question 47

Pi bonds

Answer 47

1. lateral overlap of orbitals 2. p-p orbitals only 3. weak bond 4. electron is not symmetrical and lies above nuclear plane