Equilibrium

Question 1

Reactions can go both ways. These reactions are called ________ if its easily observed both ways

Answer 1

Reversible

Question 2

Proceeds to complete OR irreversible means:

Answer 2

the reverse reaction is too slow to detect, only trace reactants remain (still in dynamic equilibrium)

Question 3

Chemical equilibrium

Answer 3

State when concentrations of reactants and products reman constant over time (things stop changing)

Question 4

On a graph what should chemical equilibrium look like

Answer 4

the lines are like parellel and straight like a equals (=) sign

Question 5

At equilibrium, the ________ and ________ reactions occur at the ______ rate

Answer 5

forward, reverse, same

Question 6

At equilibrium the ___________ are still ocurring, but there isn’t ____ ___ ___________

Answer 6

Reactions, NO NET REACTION

Question 7

Chemical equilibria are ______ and ________

Answer 7

dynamic and reversible

Question 8

aA + bB <–> cC dD equilibrium equation in a formula is what??

Answer 8

products on top reactants on bottom, a goes exponent A etc

Question 9

Reversing the reaction is just

Answer 9

inverse it OR

K(rev) = 1/k(forward)

Question 10

multiplying the reaction is just

Answer 10

Kc (double) =Kc²

or whatever it is multiplied by, put it as an exponent of original kC

Question 11

adding reactions you can ______ ____ common multiples (reaction intermediates)

Answer 11

cancel out

Question 12

,Equilibrium constants are defined as _______ ______ and why?

Answer 12

Unitless quantities and cuz its DEFINED by the activity which is just moles divided by moles

Question 13

Homogenous equilibria

Answer 13

only chemical change

Question 14

Heterogeneous equilibria

Answer 14

Chemical change AND phase change

Question 15

Pure _____ + _______ are ________ from equilibrium expressions because they are always in their ______ _____

Answer 15

Solids

liquids

excluded

standard state

Question 16

ensure K is unitless, each MUST be unitless

for a species in solution:

for a gas:

Answer 16

species: ax= [X]/[X]ref (1.0M)

For a gas:
ax = P/Pref 1.0atm

ax = 1.0

Question 17

For gases u can use _____ instead of _______

Answer 17

pressures

concentrations

Question 18

Working with gas formula

Answer 18

Kₚ = Kc (RT)Δⁿ

R is gas constant 0.08206

T is kelvin

Δn is number of moles of GASEOUS products minus GASEOUS reactants NOT THE DIFFERENCEEEEEE

Question 19

IF Kc > 10³

reaction proceeds _____ __ _______, products favoured

Answer 19

nearly to completion

Question 20

IF Kc < 10⁻³

Reaction proceeds ______ __ _____, reactants favoured

Answer 20

hardly at all

Question 21

10⁻³ < Kc < 10³

Appreciable _________ of both _____ and ______

Answer 21

concentrations

reactants

products

Question 22

Use quadratic equation when

Answer 22

u have the x stuff in a kc

Question 23

Chataliers principle

Answer 23

If stress is applied to a reaction mixture AT equilibrium, a net reaction occurs in the direction that relieves the stress.

Question 24

Examples of chatalier stresses than can be applied (3)

Answer 24

concentration of reactant or product

Pressure (and/or) volume

Temperature

Question 25

On a concentration graph, chatalier principle will show a spike of added _____, a ______ in the other reactant getting ___ __, and an _______ in the product

Answer 25

reactant decrease used up increase

Question 26

For chatalier change in concentration, use hands as added or taken out and see

Answer 26

do it

Question 27

For chatalier change in volume/pressure, REDUCING volume will _______ partial pressures and ______ total moles of gas

Answer 27

increase reduce

Question 28

For chatalier change in volume/pressure, INCREASING volume will _______ partial pressures and ______ total moles of gas

Answer 28

decrease increase

Question 29

other ways of changing pressure: adding inert will ____ Adding reactant/product gas

Answer 29

do nothing cuz partial pressures dont change Increases THAT gas's partial pressure

Question 30

For adding temp, use hands in reactant or product

Answer 30

DO IT

Question 31

sign for Kc for an exothermic reaction

Answer 31

negative , DECREASES as the temperature INCREASES DECREASE INCREASE

Question 32

sign for Kc for an endothermic reaction

Answer 32

positive , INCREASES as temp INCREASES

Question 33

For temperature Kc diagram with balls, how to tell if its endo or exo thermic

Answer 33

follow if kC INCREASE as temp INCREASE (endothermic) or if kC decrease as temp INCREASE (exo)

Question 34

How to link chemical equilibrium and kinetics: IF Kc is really large IF Kc is nearly unity IF kc is really small

Answer 34

large: Kfwd >>Krev and rxn goes almost to completion unity: Kfwd ~= Krev, products and reactants exist in equilibrium small: Krev >> Kfwd, consits mostly of reactants

Question 35

How would the rates and equilibrium constants be connected in a multi-step (overall) reaction?

Answer 35

rules of sequential equilibria Ktotal = K1K2 = (Kf1/Kr1) * (Kf2/Kr2)

Question 36

Exothermic graph will have higher or lower products? WHat is the Ea?

Answer 36

Lower (releasing energy) Ea arrow + released energy arrow

Question 37

Endothermic graph will have higher or lower products? WHat is the Ea?

Answer 37

Higher product (absorbing energy) Ea arrow BESIDE the shorter energy absorbed arrow

Question 38

What is Kc

Answer 38

equilibrium constant

Question 39

Is Kc affected by catalyst? explain

Answer 39

NO catalyst speeds up forward or reverse by SAME factor, so equilibrium misture is unchanged

Question 40

reaction quotient

Answer 40

products over reactants

Question 41

K = at equilibrium Q = current concentration they both use the same forumla. What is when K > Q What is when K < Q What is when K = Q

Answer 41

too few product, shift right too much product, shift left equilibrium, no shift