Chapter 12

Question 1

what does solubility mean?

Answer 1

the amount of substance that will dissolve in a given amount of solvent

Question 2

what does entropy mean?

Answer 2

a measure of energy randomization or energy dispersal

Question 3

what does miscible mean?

Answer 3

the ability of two or more substances to be soluble in each other in all proportions

Question 4

what are solvent-solute interactions?

Answer 4

the interactions between a solvent particle and a solute particle

1. solvent-solute interaction > solute-solute solvent-solvent interaction SOLUTION FORMS
2. solvent-solute interaction = solute-solute, solvent-solvent interaction SOLUTION FORMS
3. solvent-solute interaction

Question 5

what are solvent-solvent interactions?

Answer 5

the interactions between a solvent particle and another solvent particle

Question 6

what are solute-solute interactions?

Answer 6

the interactions between a solute particle and another solute particle

Question 7

what is a dynamic equilibrium?

Answer 7

the point at which the rate of reverse reaction is equal to the rate of the forward reaction

Question 8

what is a saturated solution?

Answer 8

a solution in which the dissolved solute is in dynamic equilibrium with any undissolved solute; any added solute will not dissolve

Question 9

what is an unsaturated solution?

Answer 9

a solution containing less than the equilibrium amount of solute; any added solute will dissolve until equilibrium is reached

Question 10

what is a super saturated solution?

Answer 10

an unstable solution in which more than the equilibrium amount of solute is dissolved

Question 11

what is recrystallization?

Answer 11

a technique used to purify solids in which the solid is put into hot solvent until the solution is saturated; when the solution cools, the purified solute comes out of the solution

Question 12

what is Henry’s Law?

Answer 12

an equation that expresses the relationship between pressure and the solubility of a gas

Sgas = kH*Pgas
Sgas = solubility of gas in mol/L
kH = the constant of proportionality 
Pgas = the partial pressure of the gas

Question 13

what is molarity (M)?

Answer 13

the amount of solute in moles divided by the volume of the solution in litres

M = amount solute (mol) / volume solution (L)

Question 14

what is molality (m)?

Answer 14

the amount of solute in moles divided by the mass of the solvent in kilograms

m = amount solute (mol) / mass solvent (kg)

Question 15

what is parts-by-mass?

Answer 15

the ratio of the mass of the solute to the mass of the solution, all multiplied by a multiplication factor

(mass solute / mass of solution)*multiplication factor

Question 16

what is parts-per-million?

Answer 16

parts-by-mass multiplied by a multiplication factor of 10^6

Question 17

what is parts-per-billion?

Answer 17

parts-by-mass multiplied by a multiplication factor of 10^9

Question 18

what is parts-by-volume?

Answer 18

the ratio of the volume of the solute to the volume of the solution, all multiplied by a multiplication factor

Question 19

what is a mole fraction?

Answer 19

the amount of of solute in moles divided by the total amount of solute and solvent in moles

Xsolute = amount solute (mol) / total amount of solute and solvent (mol)

Question 20

what is mole percent?

Answer 20

it is simply mole fraction multiplied by 100%

Question 21

what is colligative property?

Answer 21

a property that depends on the amount of solute but not on the type

Question 22

what is Raoult’s Law?

Answer 22

The larger the solvent the larger the vapour pressure of the solution

An equation used to determine the vapour pressure of a solution

Psolution = Xsolvent*Psolvent
Psolution = vapour pressure of the solution
Xsolvent = mole fraction of solvent
Psolvent = the vapour pressure of the pure solvent

Question 23

define vapour pressure lowering?

Answer 23

the difference in vapour pressure between a pure solvent and a solution of the solvent

ΔP = Psolvent - Psolution
ΔP = Xsolute*Psolvent

Question 24

what is an ideal solution?

Answer 24

a solution that follows Raoult’s Law at all concentrations for both solute and solvent

Question 25

what is freezing point depression?

Answer 25

The effect of a solute that causes a solution to have a lower melting point than the pure solvent

ΔTf = m*Kf
ΔTf = the change in temperature or the freezing point
m = the molality of the solution (mol/kg)
Kf = is the freezing point depression constant for the solvent

Question 26

what is boiling point elevation?

Answer 26

the effect of s solute that causes a solution to have a higher boiling point than the pure solvent

ΔTb = m*Kb
ΔTb = the change in temperature of the boiling point
m = the molality of the solution (mol/kg)
Kb = the boiling point elevation constant for the solvent

Question 27

what is the freezing point depression constant for water?

Answer 27

Kf = 1.86 Celsius/molality

Question 28

what is the boiling point elevation constant for water?

Answer 28

Kb = 0.512 Celsius/molality

Question 29

what is osmotic pressure?

Answer 29

The pressure required to stop osmotic flow

Π =MRT
M = molarity of the solution
T = is the temperature in kelvin K)
R = the ideal constant 0.08314barL/molK

Question 30

what is osmosis?

Answer 30

the flow of solvent from a solution of lower solute concentration to one of higher solute concentration

Question 31

what is the van’t Hoff factor (i)?

Answer 31

the ratio of particles in a solution to moles of formula units dissolved

i = moles of particles in solution / moles of formula units dissolved

Question 32

van’t Hoff’s corrections are applied to?

Answer 32

applied to the to freezing point depression, boiling point elevation and osmotic pressure determinations of IONIC solutions
ΔTf =imKf
ΔTb=imKb
Π =iMRT

Question 33

what is a colloid (colloidal dispersion)?

Answer 33

a mixture in which a dispersed substance is finely divided but not truly dissolved in a dispersing medium

Question 34

what is the Tyndall effect?

Answer 34

the scattering of light by a colloidal dispersion