Exam 3

Question 1

equilbirum

Answer 1

rate fwd = rate rev
* appears to be no change occuring
* collisions still occuring

Question 2

dynamic equilbirum

Answer 2

rate fwd = rate rev
chemicals are consumed and made at the same rate, not necessarily the same concentration

Question 3

equilbrium favors products

Answer 3

rxns that reach equilbirum after almost all reactant molecules are consumed

Question 4

equilibrium favors reactants

Answer 4

rxns that reach equilbirum after a small percentage of reactant molecules are consumed

Question 5

equilibrium systems are ___ and ___

Answer 5

dynamic
reversible

Question 6

what 2 factors do not change at equilbrium in a closed system

Answer 6

concentration and pressure

Question 7

law of mass action

Answer 7

if the system is at eq. at a given temp, then the ratio of product concentration and reactant concentration is constant
* k or kc

Question 8

eq constant for rxns with gases

Answer 8

can be expressed as the ratio of the partial pressures of the gasses

Question 9

which states of matter are not included in the expression of the eq constant

Answer 9

solids and liquids

Question 10

why are solids and liquids not included in Q and k equations

Answer 10

their [ ] are constant

Question 11

if keq = a very large number…

Answer 11

there is way more product than reactant

Question 12

if keq = a very small number…

Answer 12

way more reactant than product

Question 13

reaction quotient

Answer 13

ratio of [ ]s and/or pressures of the products and reactants in a mixture that may or may not be at equilbirum

Question 14

which way does the system need to shift when Qc<Kc

Answer 14

right

Question 15

which way does the system need to shift when Qc>Kc

Answer 15

left

Question 16

difference between Qc and Kc

Answer 16

Qc is at any time during the reaction
Kc is at eq

Question 17

for endothermic rxns, is heat a product or reactant

Answer 17

reactant

Question 18

for exothermic rxns, is heat a reactant or product

Answer 18

product

Question 19

relationship between pressure and volume

Answer 19

inverse

Question 20

what 2 conditions regarding gases have no effect on eq

Answer 20

1. inert gases
2. moles of gas particles are equal on both sides

Question 21

how does adding a catalyst effect eq and k

Answer 21

it does not, just makes system reach eq faster

Question 22

La Chatelier’s Principle

Answer 22

whenever you force a change on a system at eq, the system will move ina way to undo that change

Question 23

intert gas

Answer 23

noble gas

Question 24

partial pressure

Answer 24

pressure exerterted by an individual gas in a mixture

Question 25

relationship between partial pressure and concentration

Answer 25

direct

Question 26

given k, what is k' if the second equation is 1. doubled 2. halved 3. flipped

Answer 26

1. k^2=k' 2. k^1/2=k' 3. 1/k=k'

Question 27

when do you make an ICE table

Answer 27

when the Molarity is not at eq

Question 28

remember

Answer 28

* for kc, if both the numerator and denominator are squared, square root both sides of equation rather than expanding it

Question 29

when can you use the 5% or 400 rule

Answer 29

when kc<=a numberx10^-4

Question 30

5% rule

Answer 30

if (x/number before the -x)*100<=5

Question 31

what do you do if kc is not a very small number

Answer 31

quadratic formula

Question 32

after the quadratic formula, how do you know which x is correct

Answer 32

the x that's not negative * if both are positive, it's the x that's less than the starting amount of molarity

Question 33

Arrhenius Theory (must be in water)

Answer 33

* acid: has H+, dissociates in H2O to form H3O+ and negative ions * base: has OH group, dissociates in H2O to form OH- and positive ions

Question 34

Bronsted-Lowry Theory

Answer 34

* acid: proton donor * base: proton acceptor (doesn't need OH, has lone pair to accept H+)

Question 35

Lewis Theory

Answer 35

* acid: accepts an electron pair (doesn't need to have hydrogen) * base: donates an electron pair (doesn't need to have an OH)

Question 36

base

Answer 36

nucleophile: electron-rich

Question 37

acid

Answer 37

electrophile: electron-poor

Question 38

___ dissolve fully in water

Answer 38

salts

Question 39

monoprotic acid

Answer 39

can donate 1 H+

Question 40

diprotic acid

Answer 40

cane donate 2 H+

Question 41

polyprotic acid

Answer 41

can donate >1 H+

Question 42

Steps for ICE table

Answer 42

1. write balanced eq 2. ICE table 3. write ka equation and plug in values from E of ICE 4. set equal to ka value given 5. use 5% or 400 rule 6. solve for x 7. use x to find whatever the question asks for (pH or eq [ ])

Question 43

buffer

Answer 43

when present in solutions, they prevent dramatic changes in pH when an acid or base is added

Question 44

what is a buffer made out of

Answer 44

* weak acid and its conjugate base with a salt * weak base and its conjugate acid with a salt

Question 45

log sig fig rules

Answer 45

sig figs in answer after decimal point is the same number of sig figs in log * in other words, sigs figs of number inside log() is the number of sig figs after the decimal point in the answer ex. log 4.000 (4 s.f.) = 0.6021(4 s.f. to right of the decimal point)

Question 46

buffering capacity

Answer 46

amount of acid or base a buffer can neutralize

Question 47

when is the higher buffering capacity

Answer 47

[A-]=[HA] b/c pH=pka+log([A-]/[HA])

Question 48

buffering range

Answer 48

pH range the bugger can be effective

Question 49

when choosing an acid to make a buffer, which one do you pick

Answer 49

acid whose pka is closest to the pH of the bugger

Question 50

what equation do you use to calculate the pH of a buffer

Answer 50

henderson-hasselbalch

Question 51

inert gas

Answer 51

noble gas

Question 52

when does kp=kc

Answer 52

when the number of moles of products and reactants are equal b/c kp=kc(RT)^n

Question 53

order of proton removal in amino acids

Answer 53

acidic - COOH, R-group, amino group basic - COOH, amino group, R-group neutral - COOH, amino