Chapter 14: Mixtures and Solutions CHEMISTRY Matter and Change

Section 14.1Types of MixturesTypes of Mixtures Section 14.2Solution ConcentrationSolution Concentration Section 14.3 Factors Affecting SolvationFactors Affecting Solvation Section 14.4 Colligative Properties of SolutionsColligative Properties of Solutions Exit Click a hyperlink to view the corresponding slides. CHAPTER 14 Table Of Contents

Compare the properties of suspensions, colloids, and solutions. solute: a substance dissolved in a solution suspension colloid Brownian motion Tyndall effect soluble miscible insoluble immiscible Identify types of colloids and types of solutions. Describe the electrostatic forces in colloids. Mixtures can be either heterogeneous or homogeneous. SECTION 14.1 Types of Mixtures

A heterogeneous mixture is a mixture that does not have a uniform composition and in which the individual substances remain distinct. Suspensions are mixtures containing particles that settle out if left undisturbed. Suspensions can also be separated by filtering. –Ex. Muddy water, some clays SECTION 14.1 Types of Mixtures Heterogeneous Mixtures

Colloids are heterogeneous mixtures of intermediate sized particles (between 1 nm and 1000 nm) and do not settle out, nor can they be filtered apart. –Ex. Milk The most abundant substance in a mixture is the dispersion medium. Colloids are categorized according to the phases of their particles. SECTION 14.1 Types of Mixtures Heterogeneous Mixtures (cont.)

SECTION 14.1 Types of Mixtures Heterogeneous Mixtures (cont.)

Brownian motion is the jerky, random movements of particles in a liquid colloid, from the results of particle collisions. The Tyndall effect is the scattering of light by dispersed colloid particles. SECTION 14.1 Types of Mixtures Heterogeneous Mixtures (cont.)

Solutions are homogeneous mixtures that contain two or more substances called the solute and solvent. Most solutions are liquids, but gaseous and solid solutions exist. SECTION 14.1 Types of Mixtures Heterogeneous Mixtures (cont.)

SECTION 14.1 Types of Mixtures Heterogeneous Mixtures (cont.)

A substance that dissolves in a solvent is soluble. Two liquids that are soluble in each other in any proportion are miscible. A substance that does not dissolve in a solvent is insoluble. Two liquids that can be mixed but separate shortly after are immiscible. SECTION 14.1 Types of Mixtures Heterogeneous Mixtures (cont.)

Miscible substances are: A.two liquids that are not soluble in each other B.solids that dissolve in liquids C.solids that do not dissolve in liquids D.two liquids that are soluble in each other SECTION 14.1 Section Check

The jerky, random movement of particles in a liquid colloid is known as ____. A.Brownian motion B.Tyndall effect C.Charles’s Law D.kinetic energy SECTION 14.1 Section Check

Describe concentration using different units. solvent: the substance that dissolves a solute to form a solution concentration molarity molality mole fraction Determine the concentrations of solutions. Calculate the molarity of a solution. Concentration can be expressed in terms of percent or in terms of moles. SECTION 14.2 Solution Concentration

The concentration of a solution is a measure of how much solute is dissolved in a specific amount of solvent or solution. Concentration can be described as concentrated or dilute. SECTION 14.2 Solution Concentration Expressing Concentration

SECTION 14.2 Solution Concentration Expressing Concentration (cont.)

SECTION 14.2 Solution Concentration Expressing Concentration (cont.)

Molarity is the number of moles of solute dissolved per liter of solution. Dilution equation: M 1 V 1 = M 2 V 2 SECTION 14.2 Solution Concentration Expressing Concentration (cont.)

Molality is the ratio of moles of solute dissolved in 1 kg of solvent. SECTION 14.2 Solution Concentration Expressing Concentration (cont.)

Mole fraction is the ratio of the number of moles of solute in solution to the total number of moles of solute and solvent. SECTION 14.2 Solution Concentration Expressing Concentration (cont.)

Percentage by moles SECTION 14.2 Solution Concentration Expressing Concentration (cont.)

Which is NOT a quantitative measure of concentration? A.molarity B.molality C.percent by mass D.dilute SECTION 14.2 Section Check

The number of moles of solute divided by liters of solution is called ____. A.molarity B.molality C.percent by volume D.percent by mass SECTION 14.2 Section Check

Describe how intermolecular forces affect solvation. exothermic: a chemical reaction in which more energy is released than is required to break bonds in the initial reactants Define solubility. Understand what factors affect solubility. SECTION 14.3 Factors Affecting Solvation

solvation heat of solution unsaturated solution saturated solution supersaturated solution Henry’s law Factors such as temperature, pressure, and polarity affect the formation of solutions. SECTION 14.3 Factors Affecting Solvation

Solvation is the process of surrounding solute particles with solvent particles to form a solution. Solvation in water is called hydration. The attraction between dipoles of a water molecule and the ions of a crystal are greater than the attraction among ions of a crystal. SECTION 14.3 Factors Affecting Solvation The Solvation Process

SECTION 14.3 Factors Affecting Solvation The Solvation Process (cont.)

Sucrose molecules have several O–H bonds, which become sites for hydrogen bonding with water molecules. Oil does not form a solution with water because there is little attraction between polar water molecules and nonpolar oil molecules. SECTION 14.3 Factors Affecting Solvation The Solvation Process (cont.)

During solvation, the solute must separate into particles and move apart, which requires energy. The overall energy change that occurs during solution formation is called the heat of solution. SECTION 14.3 Factors Affecting Solvation The Solvation Process (cont.)

Stirring or shaking moves dissolved particles away from the contact surfaces more quickly and allows new collisions to occur thereby increasing the rate of solvation. Breaking the solute into small pieces increases surface area and allows more collisions to occur thereby increasing the rate of solvation. As temperature increases, rate of solvation increases. SECTION 14.3 Factors Affecting Solvation Factors That Affect Solvation

Solubility depends on the nature of the solute and solvent. Unsaturated solutions are solutions that contain less dissolved solute for a given temperature and pressure than a saturated solution. SECTION 14.3 Factors Affecting Solvation Solubility

Saturated solutions contain the maximum amount of dissolved solute for a given amount of solute at a specific temperature and pressure. Solubility is affected by increasing the temperature of the solvent because the kinetic energy of the particles increases. SECTION 14.3 Factors Affecting Solvation Solubility (cont.)

SECTION 14.3 Factors Affecting Solvation Solubility (cont.)

A supersaturated solution contains more dissolved solute than a saturated solution at the same temperature. To form a supersaturated solution, a saturated solution is formed at high temperature and then slowly cooled. Supersaturated solutions are unstable. SECTION 14.3 Factors Affecting Solvation Solubility (cont.)

SECTION 14.3 Factors Affecting Solvation Solubility (cont.)

Gases are less soluble in liquid solvents at high temperatures. Solubility of gases increases as its external pressure is increased. Henry’s law states that at a given temperature, the solubility (S) of a gas in a liquid is directly proportional to the pressure (P). SECTION 14.3 Factors Affecting Solvation Solubility (cont.)

For a given amount, which type of solution contains the LEAST amount of solute? A.solvated B.saturated C.supersaturated D.unsaturated SECTION 14.3 Section Check

At a given temperature, the solubility of a gas is directly proportional to what? A.volume B.mass C.molarity D.pressure SECTION 14.3 Section Check

Describe colligative properties. ion: an atom that is electrically charged Identify four colligative properties of solutions. Determine the boiling point elevation and freezing point depression of a solution. SECTION 14.4 Colligative Properties of Solutions

colligative property vapor pressure lowering boiling point elevation freezing point depression osmosis osmotic pressure Colligative properties depend on the number of solute particles in a solution. SECTION 14.4 Colligative Properties of Solutions

Colligative properties are physical properties of solutions that are affected by the number of particles but not by the identity of dissolved solute particles. –Colligative means depending on the collection –Colligative properties include: vapor pressure lowering, boiling point elevation, freezing point depression and osmotic pressure. SECTION 14.4 Colligative Properties of Solutions Electrolytes and Colligative Properties

Many molecular compounds do not ionize when dissolved, and do not conduct electricity, these are called nonelectrolytes. –There are some exceptions, so those molecular compounds that do ionize are electrolytes. Ionic compounds are electrolytes because they dissociate in water to form a solution that conducts electricity. –Electrolytes that produce many ions are strong electrolytes. –Electrolytes that produce only a few ions are weak electrolytes. SECTION 14.4 Colligative Properties of Solutions Electrolytes and Colligative Properties (cont.)

Adding a nonvolatile solute (one that has little tendency to become a gas) to a solvent lowers the solvent’s vapor pressure. When a solute is present, a mixture of solvent and solute occupies the surface area, and fewer particles enter the gaseous state. The greater the number of solute particles, the lower the vapor pressure. SECTION 14.4 Colligative Properties of Solutions Vapor Pressure Lowering

Vapor pressure lowering is due to the number of solute particles in solution and is a colligative property of solutions. SECTION 14.4 Colligative Properties of Solutions Vapor Pressure Lowering (cont.)

When a nonvolatile solute lowers the vapor pressure of a solvent, the boiling point is also affected. More heat is needed to supply additional kinetic energy to raise the vapor pressure to atmospheric pressure. SECTION 14.4 Colligative Properties of Solutions Boiling Point Elevation

The temperature difference between a solution’s boiling point and a pure solvent's boiling point is called the boiling point elevation. SECTION 14.4 Colligative Properties of Solutions Boiling Point Elevation (cont.)

SECTION 14.4 Colligative Properties of Solutions Boiling Point Elevation (cont.)

At a solvent's freezing point temperature, particles no longer have sufficient kinetic energy to overcome interparticle attractive forces. The freezing point of a solution is always lower than that of the pure solvent. SECTION 14.4 Colligative Properties of Solutions Freezing Point Depression

Solute particles interfere with the attractive forces among solvent particles. A solution's freezing point depression is the difference in temperature between its freezing point and the freezing point of the pure solvent. SECTION 14.4 Colligative Properties of Solutions Freezing Point Depression (cont.)

SECTION 14.4 Colligative Properties of Solutions Freezing Point Depression (cont.)

Osmosis is the diffusion of a solvent through a semipermeable membrane. SECTION 14.4 Colligative Properties of Solutions Osmotic Pressure

Osmotic pressure is the amount of additional pressure caused by water molecules that moved into the concentrated solution. SECTION 14.4 Colligative Properties of Solutions Osmotic Pressure (cont.)

Nonvolatile solutes ____ the vapor pressure of a solution. A.increase B.decrease C.do not change D.unpredictably change SECTION 14.4 Section Check

Colligative properties of a solution depend on: A.the type of solute B.the type of solvent C.the vapor pressure of the solvent D.the number of particles of solute SECTION 14.4 Section Check

Chemistry Online Study Guide Chapter Assessment Standardized Test Practice CHAPTER 14 Mixtures and Solutions Resources

Key Concepts The individual substances in a heterogeneous mixture remain distinct. Two types of heterogeneous mixtures are suspensions and colloids. Brownian motion is the erratic movement of colloid particles. Colloids exhibit the Tyndall effect. A solution can exist as a gas, a liquid, or a solid, depending on the solvent. Solutes in a solution can be gases, liquids, or solids. SECTION 14.1 Types of Mixtures Study Guide

Concentrations can be measured qualitatively and quantitatively. Molarity is the number of moles of solute dissolved per liter of solution. Molality is the ratio of the number of moles of solute dissolved in 1 kg of solvent. Study Guide Key Concepts SECTION 14.2 Solution Concentration

The number of moles of solute does not change during a dilution. M 1 V 1 = M 2 V 2 Study Guide SECTION 14.2 Solution Concentration Key Concepts

The process of solvation involves solute particles surrounded by solvent particles. Solutions can be unsaturated, saturated, or supersaturated. Henry’s law states that at a given temperature, the solubility (S) of a gas in a liquid is directly proportional to the pressure (P) of the gas above the liquid. Study Guide SECTION 14.3 Factors Affecting Solvation Key Concepts

Nonvolatile solutes lower the vapor pressure of a solution. Boiling point elevation is directly related to the solution’s molality. ∆T b = K b m A solution’s freezing point is always lower than that of the pure solvent. ∆T f = K f m Osmotic pressure depends on the number of solute particles in a given volume. Study Guide SECTION 14.4 Colligative Properties of Solutions Key Concepts

The scattering of light by dispersed solids in a colloid is known as ____. A.Tyndall effect B.Brownian motion C.Henry’s law D.Charles’s law CHAPTER 14 Mixtures and Solutions Chapter Assessment

Molality is: A.the number of moles of solute divided by liters of solution B.the volume of solute divided by liters of solution C.the volume of solute divided by the volume of solution D.the number of moles of solute divided by kg of solvent CHAPTER 14 Mixtures and Solutions Chapter Assessment

Which is NOT a type of solution? A.saturated B.unsaturated C.polyunsaturated D.supersaturated CHAPTER 14 Mixtures and Solutions Chapter Assessment

The addition of a nonvolatile solute to a solution: A.increases the freezing point of the solution B.increases the vapor pressure of the solution C.lowers the boiling point of the solution D.decreases vapor pressure of the solution CHAPTER 14 Mixtures and Solutions Chapter Assessment

Solutes in a solution can be: A.liquids only B.liquids and solids only C.gases and solids only D.gases, liquids, or solids CHAPTER 14 Mixtures and Solutions Chapter Assessment

Which is NOT an intensive physical property? A.volume B.hardness C.density D.boiling point CHAPTER 14 Mixtures and Solutions Standardized Test Practice

Cl 2 (g) + 2NO(g) → 2NOCl is what type of reaction? A.dehydration B.synthesis C.fusion D.replacement CHAPTER 14 Mixtures and Solutions Standardized Test Practice

If 8 mol of H 2 is used, how many moles of Fe will be produced? Please note: Assume H 2 is the limiting reactant Fe 3 O 4 (s) + 4H 2 →3Fe(s) + 4H 2 O(l) A.2 B.3 C.4 D.6 CHAPTER 14 Mixtures and Solutions Standardized Test Practice

Which is NOT a colligative property? A.heat of solution B.boiling point elevation C.vapor pressure lowering D.freezing point depression CHAPTER 14 Mixtures and Solutions Standardized Test Practice

Nonvolatile solutes _____ the boiling point of a solution. A.increase B.decrease C.do not change D.unpredictably change CHAPTER 14 Mixtures and Solutions Standardized Test Practice

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