chapter 6: equilibrium

Question 1

what is the equilibrium constant

Answer 1

K
K = [prod]/[react]

Question 2

what does it mean if K >1, K<1

Answer 2

the reaction is product favored, reactant favored

Question 3

do equilibrium constants have dimensions

Answer 3

no, they are dimensionless

Question 4

in the equation aA+bB = cC+ dD what happens if A is a soute and when D is a gas

Answer 4

• A is a solute, [A] = 1/M
  M = moles of solute /Liters
• D is a gas, means that the pressure of D in bars/ 1 bar and written as Pd

Question 5

what state is each quantitiy in the ratio given

Answer 5

at standard state

Question 6

what are the different standard states

Answer 6

1. conc. of solutes = mol/ L
2. conc. of gases = bars
3. do not include solids,liquids, and solvents because they are unity

Question 7

what are some ways to manipulate the equilibrium constant

Answer 7

1. reaction is reverse = 1/K
2. two reactions are added together = multiply them together to get the new K
3. if n reaction is added then K is the product of the n individual equilibrium constants

Question 8

what is enthalpy

Answer 8

heat absorbed or released

Question 9

what is entropy

Answer 9

the dispersal of energy into molecular motions, random

Question 10

what is the enthalpy change

Answer 10

heat absorbed or released

Question 11

what is the standard enthalpy change

Answer 11

heat absorbed when all reactants and products are in their standard states

Question 12

if it is delta H is negative

Answer 12

exothermic

Question 13

delta H is positive

Answer 13

endothermic

Question 14

what is the symbol for entropy

Answer 14

delta S

Question 15

what is the equation for entrop

Answer 15

S = qrev( heat abosrbed) / Temperature (kelvin)

Question 16

what does a positive q mean what does a negative q mean

Answer 16

1. heat is absorbed
2. heat is removed

Question 17

what states have higher entropy than the other

Answer 17

gas> liquid> solid

Question 18

if S is positive, if S is negative

Answer 18

1. greater entropy than reactants
2. lower entropy than the reactants

Question 19

which has more entropy, ions or solid salt

Answer 19

ions

Question 20

what pushes a chemical reaction in the forward reaction

Answer 20

1. H is (-)
2. S is (+)
   or both,
   reaction is disfavored in the reverse reaction

Question 21

what will decide whether the reaction will be favored if both H and S are positive

Answer 21

the gibbs free energy

Question 22

What is the equation for gibbs free energy

Answer 22

G = change in H - T(change in S)

Question 23

what sign is G if it is favored

Answer 23

negative

Question 24

if G is negative what does it tell us about H and T

Answer 24

H has greater favorable influence than S because so it means that H is more negative

Question 25

what is the equation for K using Gibbs

Answer 25

K = e^(change in G)/ RT

Question 26

if K is greater than 1 what does it tell us about G

Answer 26

that G is negative because it is product favored reaction

Question 27

what does a large K tell us

Answer 27

that something is very soluble in water

Question 28

if K is greater than 1 is the reaction spontaneous

Answer 28

yes it is and it is not spontaneous when K is less than 1( because G is positive)

Question 29

what is the Le chatelier’s principle

Answer 29

the direction in which the system proceeds to move back to equilibrium

Question 30

1. q<k
2. q>k
   3.q=k

Answer 30

1. reactant favored
2. product favored
3. at equilibrium

Question 31

what is the difference between thermodynamics and kinetics

Answer 31

1. thermodynamics tells us the direction of the equation and kinetics tells us how fast it is going

Question 32

what is the Ksp

Answer 32

equilibrium constant that gives us more information on how soluble a salt can be

Question 33

what is a saturated solution

Answer 33

equilibrium with excess and undissolved solid

Question 34

what happens if there is an aqeuous solution that is still left in contact with the excess solid

Answer 34

the solid will dissolve until the Ksp is satisfied

Question 35

what is a mercurous ion Hg+

Answer 35

dimer that consists of two identical units bound together

Question 36

what is disproportionation

Answer 36

the process in which an element in an intermediate oxidation state, gives products in both the higher and lower oxidation states

Question 37

what reactions does solubility not account for

Answer 37

1. hydrolysis
2. disproportionation
3. ion pairing

Question 38

what is the common ion effect

Answer 38

salt is LESS soluble if one of its constituent ions is already present in the solution.

Question 39

what does a small ksp indicate

Answer 39

that the reaction is less soluble

Question 40

what is a complex ion

Answer 40

anion that precipitate metals are observed to form complex ions

Question 41

what is a ligand

Answer 41

any atom or group of atoms attached to species of interest

Question 42

what is an example of a ligand attached to a complex ion

Answer 42

1. PbI+, PbI3 and PbI
   - I is the ligand
   - Pb is a lewis acid and I is a lewis Base

Question 43

if anion X- precipitates metal M+, what is observed

Answer 43

high concentration of X- causes solid MX to redissolve
- increased solubility arises from the formation of complex ions like MX-2