CHEMISTRY Matter and Change

CHEMISTRY Matter and Change
Chapter 14: Mixtures and Solutions

Table Of Contents Section 14.2 Solution Concentration
CHAPTER14 Table Of Contents Section 14.2 Solution Concentration Section Factors Affecting Solvation Section Colligative Properties of Solutions Click a hyperlink to view the corresponding slides. Exit

Types of Mixtures solute: a substance dissolved in a solution
SECTION14.1 Types of Mixtures Compare the properties of suspensions, colloids, and solutions. solute: a substance dissolved in a solution 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.

Solution Concentration
SECTION14.2 Solution Concentration solvent: the substance that dissolves a solute to form a solution Describe concentration using different units. Determine the concentrations of solutions. Calculate the molarity of a solution. concentration molarity molality mole fraction Concentration can be expressed in terms of percent or in terms of moles.

SECTION14.2 Solution Concentration Expressing 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.

SECTION14.2 Solution Concentration Expressing Concentration (cont.)

Example 1: In order to maintain a sodium chloride concentration similar to ocean water, an aquarium must contain 3.6g NaCl per 100.0g of water. What is the percent by mass of NaCl?

Ex. 2) What is the percent by volume of ethanol in a solution that contains 35 mL of ethanol dissolved in 155 mL of water?

SECTION14.2 Solution Concentration Expressing Concentration (cont.) Molarity is the number of moles of solute dissolved per liter of solution. Dilution equation: M1V1 = M2V2

Ex. 3) A 100. 5-mL intravenous solution contains 5. 10g of glucose
Ex. 3) A mL intravenous solution contains 5.10g of glucose. What is the molarity of this solution? The molar mass of C6H12O6 is g/mol.

SECTION14.2 Solution Concentration Expressing Concentration (cont.) Molality is the ratio of moles of solute dissolved in 1 kg of solvent.

What volume in milliliters of 2
What volume in milliliters of 2.00M calcium chloride (CaCl2) stock solution would you use to make 0.50L of M calcium chloride solution?

SECTION14.2 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.

SECTION14.2 Solution Concentration Expressing Concentration (cont.) Percentage by moles

Which is NOT a quantitative measure of concentration?
SECTION14.2 Section Check Which is NOT a quantitative measure of concentration? A. molarity B. molality C. percent by mass D. dilute

SECTION14.2 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

Factors Affecting Solvation
SECTION14.3 Factors Affecting Solvation 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.

SECTION14.3 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.

SECTION14.3 Factors Affecting Solvation The Solvation Process 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.

SECTION14.3 Factors Affecting Solvation The Solvation Process (cont.)

SECTION14.3 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.

SECTION14.3 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.

SECTION14.3 Factors Affecting Solvation Factors That Affect Solvation 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.

SECTION14.3 Factors Affecting Solvation Solubility 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.

SECTION14.3 Factors Affecting Solvation Solubility (cont.) 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.

SECTION14.3 Factors Affecting Solvation Solubility (cont.)

SECTION14.3 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.

SECTION14.3 Factors Affecting Solvation Solubility (cont.)

SECTION14.3 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).

SECTION14.3 Section Check For a given amount, which type of solution contains the LEAST amount of solute? A. solvated B. saturated C. supersaturated D. unsaturated

SECTION14.3 Section Check At a given temperature, the solubility of a gas is directly proportional to what? A. volume B. mass C. molarity D. pressure

Colligative Properties of Solutions
SECTION14.4 Colligative Properties of Solutions 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.

SECTION14.4 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.

SECTION14.4 Colligative Properties of Solutions Electrolytes and Colligative Properties 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.

SECTION14.4 Colligative Properties of Solutions Electrolytes and Colligative Properties (cont.) 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. 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.

SECTION14.4 Colligative Properties of Solutions Vapor Pressure Lowering 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.

SECTION14.4 Colligative Properties of Solutions Vapor Pressure Lowering (cont.) Vapor pressure lowering is due to the number of solute particles in solution and is a colligative property of solutions.

SECTION14.4 Colligative Properties of Solutions Boiling Point Elevation 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.

SECTION14.4 Colligative Properties of Solutions Boiling Point Elevation (cont.) The temperature difference between a solution’s boiling point and a pure solvent's boiling point is called the boiling point elevation.

SECTION14.4 Colligative Properties of Solutions Boiling Point Elevation (cont.)

SECTION14.4 Colligative Properties of Solutions Freezing Point Depression 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.

SECTION14.4 Colligative Properties of Solutions Freezing Point Depression (cont.) 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.

SECTION14.4 Colligative Properties of Solutions Freezing Point Depression (cont.)

Examples: 1.) Calculate the freezing point depression of a solution of 100.g of ethylene glycol (C2H6O2) antifreeze in 0.500kg of H2O. Kf for water is 1.86C/m.

2.) When ethylene glycol (C2H6O2) is added to 1675 g of water, the boiling point of the solution is 104.6C. How many grams of ethylene glycol were added? Kb for water is 0.52 C/m.

SECTION14.4 Colligative Properties of Solutions Osmotic Pressure Osmosis is the diffusion of a solvent through a semipermeable membrane.

SECTION14.4 Colligative Properties of Solutions Osmotic Pressure (cont.) Osmotic pressure is the amount of additional pressure caused by water molecules that moved into the concentrated solution.

Nonvolatile solutes ____ the vapor pressure of a solution.
SECTION14.4 Section Check Nonvolatile solutes ____ the vapor pressure of a solution. A. increase B. decrease C. do not change D. unpredictably change

Colligative properties of a solution depend on:
SECTION14.4 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

Mixtures and Solutions
CHAPTER14 Mixtures and Solutions Resources Chemistry Online Study Guide Chapter Assessment Standardized Test Practice

Types of Mixtures Key Concepts
SECTION14.1 Types of Mixtures Study Guide 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.

SECTION14.2 Solution Concentration Study Guide Key Concepts 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.

SECTION14.2 Solution Concentration Study Guide Key Concepts The number of moles of solute does not change during a dilution. M1V1 = M2V2

SECTION14.3 Factors Affecting Solvation Study Guide 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.

SECTION14.4 Colligative Properties of Solutions Study Guide Key Concepts Nonvolatile solutes lower the vapor pressure of a solution. Boiling point elevation is directly related to the solution’s molality. ∆Tb = Kbm A solution’s freezing point is always lower than that of the pure solvent. ∆Tf = Kfm Osmotic pressure depends on the number of solute particles in a given volume.

CHAPTER14 Mixtures and Solutions Chapter Assessment 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

CHAPTER14 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

CHAPTER14 Mixtures and Solutions Chapter Assessment Which is NOT a type of solution? A. saturated B. unsaturated C. polyunsaturated D. supersaturated

CHAPTER14 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

CHAPTER14 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

CHAPTER14 Mixtures and Solutions Standardized Test Practice Which is NOT an intensive physical property? A. volume B. hardness C. density D. boiling point

CHAPTER14 Mixtures and Solutions Standardized Test Practice Cl2(g) + 2NO(g) → 2NOCl is what type of reaction? A. dehydration B. synthesis C. fusion D. replacement

CHAPTER14 Mixtures and Solutions Standardized Test Practice If 8 mol of H2 is used, how many moles of Fe will be produced? Please note: Assume H2 is the limiting reactant Fe3O4(s) + 4H2 →3Fe(s) + 4H2O(l) A. 2 B. 3 C. 4 D. 6

CHAPTER14 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

CHAPTER14 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

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