After Exam 3

Question 1

if you’re making a buffer with a W/S species, the ___ will always be in the greater amount

Answer 1

weak species

Question 2

if you’re making a buffer with a CA/CB and the pKa of the acid is > than the pH you want…

Answer 2

the acid will be greater in amount

Question 3

if you’re making a buffer with a CA/CB and the pKa of the acid is < than the pH you want…

Answer 3

the base will be in greater amount

Question 4

the sign of G will always be the same as…

Answer 4

the sign of H

Question 5

at the switch temp, what changes?

Answer 5

the sign of delta G (either spontaneous –> not spontaneous or vise-versa)

Question 6

spontaneity will only switch temps if…

Answer 6

ΔH and ΔS have the same sign

Question 7

if ΔH = (+) and ΔS = (+)…

Answer 7

there is a switch temp at T = ΔH/ΔS

Question 8

if ΔH = (-) and ΔS = (-)…

Answer 8

there is a switch temp at T = ΔH/ΔS

Question 9

if ΔG > 0…

Answer 9

K < 1, ΔS < 0, not spontaneous

Question 10

if ΔG < 0…

Answer 10

K > 1 (Kforward > Kbackwards), ΔS > 0, spontaneous

Question 11

if ΔH = (-), the reaction is…

Answer 11

exothermic (releases energy)

Question 12

if ΔH = (+), the reaction is…

Answer 12

endothermic (absorbs energy)

Question 13

order of strength of IMF bonds

Answer 13

London < dipole < H-bond

Question 14

E = (-) Voltage =

Answer 14

NOT spontaneous

Question 15

E = (+) Voltage =

Answer 15

spontaneous

Question 16

A + B –> C + D = __/ __ || __/__

Answer 16

A / C || B / D

Question 17

loss of electrons =

Answer 17

LEO
- oxidation
- reducing agent

Question 18

reducing agent is a ___

Answer 18

product

Question 19

gain of electrons =

Answer 19

GER
- reduction
- oxidizing agent

Question 20

oxidizing agent is a ___

Answer 20

reactant

Question 21

Reduction Table: if the slope from the reducing agent –> oxidizing agent is (-)…

Answer 21

NOT spontaneous

Question 22

Reduction Table: if the slope from the reducing agent –> oxidizing agent is (+)…

Answer 22

spontaneous!

Question 23

voltaic (galvanic) cell =

Answer 23

(E) Voltage = (+) = spontaneous!

Question 24

electrolytic cell =

Answer 24

(E) Voltage = (-) = NOT spontaneous

Question 25

breaking bonds…

Answer 25

requires energy = endothermic

Question 26

exothermic =

Answer 26

release heat/energy = ΔH = (-)

Question 27

making bonds…

Answer 27

releases energy = exothermic

Question 28

endothermic =

Answer 28

requires heat/energy = ΔH = (+)

Question 29

molality

Answer 29

mol / kg

Question 30

colligative properties

Answer 30

depends on concentration ONLY
- generally: [solute]*(constant)

Question 31

vapor pressure

Answer 31

VPL = molality solute

Question 32

osmotic pressure

Answer 32

pressure(∏) = molality(T)

Question 33

boiling point elevation

Answer 33

BPE - ΔTb = Kb * [molality]

Question 34

increase (largest) in molality causes a…

Answer 34

↑ in boiling point and a ↓ in freezing point

Question 35

freezing point depression

Answer 35

FPD - ΔTf = Kf * [molality]

Question 36

calculating molality for colligative properties you…

Answer 36

(number of ions in solution)*(original molality)

Question 37

the lowest freezing point?

Answer 37

largest molality

Question 38

the highest boiling point?

Answer 38

largest molality

Question 39

in order for a substance to have colligative properties, it must be..

Answer 39

a SOLUTION, not a pure substance (ie: NOT water or methanol)

Question 40

4 colligative properties

Answer 40

vapor pressure, osmotic pressure, boiling point (elevation), freezing point (depression)