Equilibrium

Question 1

chemical equilibrium

Answer 1

state where the forward reaction rate(rf) is equal to the reverse reaction rate(rr)

Question 2

dynamic equilibria

Answer 2

there is constant movement and each species is actively consumed and actively formed

Question 3

criteria for a system to be in equilibrium

Answer 3

1. constant macroscopic properties
2. closed system
3. shift in response to changes

Question 4

macroscopic property

Answer 4

property observed with the naked eye

Question 5

criteria: macroscopic properties

Answer 5

should have constant concentrations, pH, color, and temperature

Question 6

closed system

Answer 6

a system where chemicals do not enter or leave

Question 7

steady state

Answer 7

system that appears to be at equilibrium but chemicals are entering and leaving the system at the same time

Question 8

criteria: shift in response

Answer 8

a change(stress) causes the system to respond

Question 9

equilibrium stages: 1

Answer 9

reactant concentrations are high, rf is at the highest

Question 10

equilibrium stages: 2

Answer 10

[A] and [B] and rf decreases
[C] and [D] and rr increases

Question 11

equilibrium stages: 3

Answer 11

[A] [B] [C] [D] are constant and rr and rf are equal

Question 12

Le Chatlier’s principle

Answer 12

an equilibrium when subjected to stress will shift to alleviate the stress

Question 13

stress

Answer 13

any change that favors rf or rr

Question 14

stress: change in concentration

Answer 14

if the concentration of a chemical species increases, then the system will shift to consume that species; if the concentration decreases, the system will shift to produce that species

Question 15

shift right

Answer 15

when a system shifts to favor the products

Question 16

shift left

Answer 16

when a system shifts to favor the reactants

Question 17

adding a catalyst

Answer 17

does not affect equilibrium, but systems will alleviate the stresses applied faster

Question 18

equilibrium position

Answer 18

relative concentrations of chemical species in equilibrium expressed in percent yield

Question 19

shift right

Answer 19

if the percent yield is above 50%

Question 20

shift left

Answer 20

if the percent yield is less than 50%

Question 21

partial pressure

Answer 21

pressure exerted by an individual gas in a mixture

Question 22

partial pressure is to gaseous equilibria as

Answer 22

osmotic pressure is to solution equilibria

Question 23

gas pressure is directly proportional to gas concentration and

Answer 23

osmotic pressure is directly proportional to solution concentration

Question 24

stress: change in volume

Answer 24

the side of equilibrium with the greater sum of coefficients will be more sensitive to volume change

Question 25

stress: change in temperature

Answer 25

a system in equilibrium will shift to replace lost kinetic energy or shift to remove added kinetic energy

Question 26

a system in equilibria will shift

Answer 26

before the stress is fully applied

Question 27

when heat is added

Answer 27

the endothermic direction is favored

Question 28

Haber Bosch Reaction

Answer 28

N2 +3H2 -> 2NH3 +92.4 kJ

Question 29

haber reactor pressure

Answer 29

increased to 3.5 x 10^4 kPa

Question 30

equilibrium expression

Answer 30

formula for finding the equilibrium constant in terms of concentrations of products and reactants

Question 31

equilibrium constant(keq)

Answer 31

numerical value that related the concentrations of products to the concentration of reactants in equilibria

Question 32

keq requirements

Answer 32

-units vary and are not required to be expressed -temperature dependent

Question 33

products are favored, shift right

Answer 33

keq > 1

Question 34

reactants are favored, shift left

Answer 34

keq < 1

Question 35

equilibrium law

Answer 35

the expression of a balanced chemical equation and an equilibrium expression together

Question 36

reaction quotient(Q or trial keq)

Answer 36

numerical value calculated from taking any set of concentrations and plugging them into an equilibrium expression

Question 37

shift left

Answer 37

Q>Keq

Question 38

shift right

Answer 38

Q

Question 39

exception to le chatelier

Answer 39

if only one chemical species is present in an equilibrium expression, the system will shift to completely alleviate a stress that affects its concentration

Question 40

ICE Box

Answer 40

table that is used to solve calculations in systems of equilibria where ICE is an acronym -concentrations needs to be in molarity -pay attention to the coefficients

Question 41

mass action expression

Answer 41

equilibrium expressions in terms of concentration or partial pressure

Question 42

14.7 psi

Answer 42

psi in atm

Question 43

760 mmHg

Answer 43

mmHg in atm

Question 44

Kp=

Answer 44

Kc(RT)^(delta n)

Question 45

delta n=

Answer 45

(c+d)-(a+b)

Question 46

ideal gas law constant(R)

Answer 46

0.08206 (L x atm)/(mol x K)