Non-Ideal solution

Question 1

non-ideal solution

Answer 1

molecules don’t interact identically therefore behaviour of one molecule depend on composition of solution

Question 2

arrangement of molecules

Answer 2

non-random - strong attraction = closer

Question 3

non-ideality

Answer 3

frequently observed IRL and make necessary to extend thermodynamics analysis

Question 4

equation for chemical potential - calculate concentration

Answer 4

μx = μx* + RTln[ax]

Question 5

concentration/activity, ax

Answer 5

calculated concentration

Question 6

activity coefficient - Yx equation

Answer 6

Yx = ax / [x]

Question 7

[x]

Answer 7

actual concentration

Question 8

ax

Answer 8

effective concentration

Question 9

ax = [x]

Answer 9

ideal solution

Question 10

how much Yx deviates from 1

Answer 10

how different solution is from ideal

Question 11

effective equation - μx

Answer 11

μx = μx* + RTlnYx[x]

Question 12

Yx converting [x] into ax

Answer 12

has physical significance - used to measure amount of solution deviated from ideal

Question 13

ax in a graph

Answer 13

concentrated predicted by ideal model to have same μ as actual

Question 14

if Y = 1

Answer 14

ideal solution

Question 15

Y < 1

Answer 15

x is more stable than predicted model

Question 16

Y > 1

Answer 16

x is less stable than predicted model

Question 17

non-ideal +ve deviation from Raoult’s law

Answer 17

DH{mix} > 0 - endothermic - heat absorbed upon mixing

Total V > sum of V of components

Question 18

non-ideal -ve deviation from Raoult’s law

Answer 18

DH{mix} < 0 - exothermic - heat evolved upon mixing

Total V < sum of V of component

Question 19

ionic solution

Answer 19

requires knowledge of deviation for ideality

Question 20

ionic solution example - NaCl in water

Answer 20

O2 - more electronegative than H therefore strong attraction between solvent-solvent molecule
Na+ and Cl- disrupt water bonds by hydration shell formed
has electrostatic interaction

Question 21

dilute ionic solution

Answer 21

don’t cause non-ideal behaviour at low concentration

has affect on enthalpy and entropy when ions dissolve in water

Question 22

enthalpy

Answer 22

ion-water electrostatic interaction is more than compensated for loss of water-water H bonds
DH = -ve

Question 23

entropy

Answer 23

decreases as ions added to water - less disorder

water around ion - in particular arrangement

Question 24

more concentrated ionic solution

Answer 24

significance in electrostatic interaction - charges repel and attract

Question 25

DH - change in enthalpy

Answer 25

transferring ions from gas phase to solution

Question 26

smaller ions in solution

Answer 26

large DH and D entropy - strong interaction with water

Question 27

Debye-Huckel theory equation

calculating solute-solute electrostatic interaction in solution

Answer 27

log{10}Yx = -Az{x}(square root I)

Question 28

finding ionic strength equation

Answer 28

I = 1/2 sum of c{x}Z{x}(2)