Chapter 13 1

Properties of SolutionsProperties of Solutions

Chapter 13Chapter 13

Chapter 13 2

Homework

13.10, 13.18, 13.26, 13.32, 13.44, 13.46, 13.48, 13.56

Chapter 13 3

The Solution ProcessThe Solution Process

Solution - A homogeneous mixture composed of a solute and a solvent.Solute – The substance which is dissolved.Solvent – The substance which acts as the dissolving

medium.

Chapter 13 4

Saturated Solutions and SolubilitySaturated Solutions and Solubility

Qualitative Terms: Dilute Solution – A solution in which additional solute may be dissolved.Saturated Solution – A solution in which no more solute may be dissolved. Supersaturated Solution – A solution in which more solute is dissolved than in a saturated solution.

Solubility - amount of solute required to form a saturated solution.

Mole Fraction, Molarity, and Molality

Chapter 13 5

Ways of Expressing ConcentrationWays of Expressing Concentration

100soln of mass total

soln incomponent of mass % Mass

Chapter 13 6

Ways of Expressing ConcentrationWays of Expressing Concentration

100soln of mass total

soln incomponent of mass % Mass

610soln of mass total

soln incomponent of massppm

Chapter 13 7

Ways of Expressing ConcentrationWays of Expressing Concentration

components all of moles totalcomponent of molesfraction Mole

Mole Fraction

Chapter 13 8

Ways of Expressing ConcentrationWays of Expressing Concentration

solution of literssolute of molesMolarity

Molarity

Chapter 13 9

Ways of Expressing ConcentrationWays of Expressing Concentration

Molality (m) – moles of solute per kilogram of solvent

Molality

Chapter 13 10

Ways of Expressing ConcentrationWays of Expressing Concentration

Molality (m) – moles of solute per kilogram of solvent

solvent of kilogramssolute of molesMolality

Molality

Chapter 13 11

Factors Affecting SolubilityFactors Affecting Solubility

Miscible liquids - Mix in any proportions.Immiscible liquids - Do not mix.

Solute-Solvent Interactions

Chapter 13 12

Factors Affecting SolubilityFactors Affecting Solubility

“Like Dissolves Like”- Polar molecules will dissolve in polar solvents.- Non-polar molecules will dissolve in non-polar

solvents.

Solute-Solvent Interactions

Chapter 13 13

Factors Affecting SolubilityFactors Affecting Solubility

- Solubility of a gas in a liquid is a function of the pressure of the gas.- The higher the pressure, the greater the solubility.

Pressure Effects

Chapter 13 14

Factors Affecting SolubilityFactors Affecting Solubility

Henry’s Law – The solubility of a gas increases in direct proportion to its partial pressure above the solution.

Pressure Effects

Chapter 13 15

Factors Affecting SolubilityFactors Affecting Solubility

Henry’s Law – The solubility of a gas increases in direct proportion to its partial pressure above the solution.

Cg - solubility of gas Pg - the partial pressure of the gas k - Henry’s law constant.

gg kPC

Pressure Effects

Chapter 13 16

Factors Affecting SolubilityFactors Affecting SolubilityTemperature EffectsTemperature Effects

Chapter 13 17

Factors Affecting SolubilityFactors Affecting SolubilityTemperature EffectsTemperature Effects

Chapter 13 18

Colligative PropertiesColligative Properties

- Properties of a solution which depend on quantity of solute molecules.

- Solutions formed with a nonvolatile solute will:- have lower vapor pressure- lower freezing point- higher boiling point

Chapter 13 19

Colligative PropertiesColligative PropertiesBoiling-Point Elevation

Chapter 13 20

Colligative PropertiesColligative Properties

Raoult’s Law – The equilibrium vapor pressure of the solvent over the solution is directly proportional to the mole fraction of the solvent in the solution

Raoult’s Law

Chapter 13 21

Colligative PropertiesColligative Properties

Raoult’s Law – The equilibrium vapor pressure of the solvent over the solution is directly proportional to the mole fraction of the solvent in the solution

PA - vapor pressure of the solvent in the solutionPA - vapor pressure of the pure solvent A - the mole fraction of solvent, A

AAA PP

Raoult’s Law

Chapter 13 22

Colligative PropertiesColligative Properties

Kb - Molal boiling-point elevation constant m – solution molalityTb – boiling point change

mKΔT bb

Boiling-Point Elevation

Chapter 13 23

Colligative PropertiesColligative Properties

Kf - Molal freezing-point depression constant m – solution molalityTf – freezing point change

mKT ff

Freezing-Point Depression

Chapter 13 24

Colligative PropertiesColligative Properties

The net movement of solvent through a semi-permeable membrane from a dilute to a concentrated solution.

Osmosis

Chapter 13 25

Colligative PropertiesColligative Properties

Eventually the pressure difference between the arms stops osmosis.

Osmosis

Chapter 13 26

Colligative PropertiesColligative Properties

Osmotic pressure() - The pressure required to stop osmosis

Osmosis

Chapter 13 27

Colligative PropertiesColligative Properties

Osmotic pressure() - The pressure required to stop osmosis

M - molarity of the solutionR - gas constant (0.08206 L(atm)/mol(K))T - temperature in Kelvin

MRT

Osmosis

Chapter 13 28

ColloidsColloids

- Colloids are suspensions in which the suspended particles are larger than molecules but too small to drop out of the suspension due to gravity.

- Particle size: 10 to 2000 Å.

Chapter 13 29

ColloidsColloidsTyndall effect: ability of a Colloid to scatter light. The

beam of light can be seen through the colloid.