16.1 Properties of Solutions > 1 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Chapter 16 Solutions 16.1 Properties of Solutions 16.2 Concentrations of Solutions 16.3 Colligative Properties of Solutions 16.4 Calculations Involving Colligative Properties

16.1 Properties of Solutions > 2 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Solution Formation What factors affect how fast a substance dissolves?

16.1 Properties of Solutions > 3 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Solution Formation Granulated sugar dissolves faster than sugar cubes, and both granulated sugar and sugar cubes dissolve faster in hot tea or when you stir the tea.

16.1 Properties of Solutions > 4 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Solution Formation The compositions of the solvent and the solute determine whether or not a substance will dissolve. Factors that affect how fast a substance dissolves include: Agitation Temperature Particle size of the solute

16.1 Properties of Solutions > 5 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Solution Formation Agitation If the contents of the glass are stirred, the crystals dissolve more quickly. The dissolving process occurs at the surface of the sugar crystals. Stirring speeds up the process because fresh solvent (the water) is continually brought in contact with the surface of the solute (sugar).

16.1 Properties of Solutions > 6 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Solution Formation Agitation Agitation (stirring or shaking) affects only the rate at which a solid solute dissolves. It does not influence the amount of solute that will dissolve. An insoluble substance remains undissolved regardless of how vigorously or for how long the solvent/solute system is agitated.

16.1 Properties of Solutions > 7 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Solution Formation Temperature also influences the rate at which a solute dissolves. Sugar dissolves much more rapidly in hot tea than in iced tea. Temperature

16.1 Properties of Solutions > 8 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Solution Formation Temperature At higher temperatures, the kinetic energy of water molecules is greater than at lower temperatures, so the molecules move faster. The more rapid motion of the solvent molecules leads to an increase in the frequency of the force of the collisions between water molecules and the surfaces of the sugar crystals.

16.1 Properties of Solutions > 9 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Solution Formation Particle Size of the Solute The rate at which a solute dissolves also depends upon the size of the solute particles. The smaller particles in granulated sugar expose a much greater surface area to the colliding water molecules.

16.1 Properties of Solutions > 10 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Solution Formation Particle Size of the Solute The dissolving process is a surface phenomenon. The more surface area of the solute that is exposed, the faster the rate of dissolving.

16.1 Properties of Solutions > 11 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Which of the following will not speed up the rate at which a solid solute dissolves? A.Increasing the temperature B.Stirring the mixture C.Crushing the solute D.Decreasing the temperature

16.1 Properties of Solutions > 12 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Which of the following will not speed up the rate at which a solid solute dissolves? A.Increasing the temperature B.Stirring the mixture C.Crushing the solute D.Decreasing the temperature

16.1 Properties of Solutions > 13 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Solubility Solubility How can you describe the equilibrium in a saturated solution?

16.1 Properties of Solutions > 14 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Solubility What is happening in this figure?

16.1 Properties of Solutions > 15 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Solubility What is happening in this figure? Particles move from the solid into the solution. Some dissolved particles move from the solution back to the solid. Because these two processes occur at the same rate, no net change occurs in the overall system.

16.1 Properties of Solutions > 16 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Solubility Such a solution is said to be saturated.

16.1 Properties of Solutions > 17 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Solubility Such a solution is said to be saturated. A saturated solution contains the maximum amount of solute for a given quantity of solvent at a constant temperature and pressure.

16.1 Properties of Solutions > 18 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Solubility The solubility of a substance is the amount of solute that dissolves in a given quantity of a solvent at a specified temperature and pressure to produce a saturated solution. Solubility is often expressed in grams of solute per 100 g of solvent (g/100 g H 2 O). Sometimes the solubility of a gas is expressed in grams per liter of solution (g/L).

16.1 Properties of Solutions > 19 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Solubility A solution that contains less solute than a saturated solution at a given temperature and pressure is an unsaturated solution. If additional solute is added to an unsaturated solution, the solute will dissolve until the solution is saturated.

16.1 Properties of Solutions > 20 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Solubility Some liquids—for example, water and ethanol—are infinitely soluble in each other. Two liquids are miscible if they dissolve in each other in all proportions.

16.1 Properties of Solutions > 21 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Solubility Liquids that are insoluble in each other are immiscible. Oil and water are examples of immiscible liquids.

16.1 Properties of Solutions > 22 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. The solubility of a substance is often expressed as which of the following? A.grams of solute per 100 liters of solvent B.grams of solute per 1 cm 3 of solvent C.grams of solute per 100 grams of solvent D.grams of solute per 100 grams of solution

16.1 Properties of Solutions > 23 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. The solubility of a substance is often expressed as which of the following? A.grams of solute per 100 liters of solvent B.grams of solute per 1 cm 3 of solvent C.grams of solute per 100 grams of solvent D.grams of solute per 100 grams of solution

16.1 Properties of Solutions > 24 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Factors Affecting Solubility What factors affect the solubility of a substance?

16.1 Properties of Solutions > 25 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Temperature The solubility of most solid substances increases as the temperature of the solvent increases. Interpret Graphs Temperature (°C) Solubility (g/100g H 2 O)

16.1 Properties of Solutions > 26 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Temperature The solubility of most solid substances increases as the temperature of the solvent increases. Interpret Graphs Temperature (°C) Solubility (g/100g H 2 O) For a few substances, solubility decreases with temperature.

16.1 Properties of Solutions > 27 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Solubilities of Substances in Water at Various Temperatures Solubility (g/100 g H 2 O) SubstanceFormula0°C0°C20°C50°C100°C Barium hydroxideBa(OH) —— Barium sulfateBaSO — Calcium hydroxideCa(OH) — 0.07 Potassium chlorateKClO Potassium chlorideKCl Sodium chlorideNaCl Sodium nitrateNaNO Aluminum chlorideAlCl Silver nitrateAgNO Sucrose (table sugar)C 12 H 22 O HydrogenH2H OxygenO2O Carbon dioxideCO Interpret Data

16.1 Properties of Solutions > 28 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Factors Affecting Solubility A supersaturated solution contains more solute than it can theoretically hold at a given temperature. The crystallization of a supersaturated solution can be initiated if a very small crystal, called a seed crystal, of the solute is added. Temperature

16.1 Properties of Solutions > 29 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Factors Affecting Solubility The rate at which excess solute deposits upon the surface of a seed crystal can be very rapid. The solution is clear before a seed crystal is added. Crystals begin to form immediately after the addition of a seed crystal. Excess solute crystallizes rapidly.

16.1 Properties of Solutions > 30 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. CHEMISTRY & YOU How do you think crystal-growing kits work? Use what you know about solubility and supersaturated solutions to explain your answer.

16.1 Properties of Solutions > 31 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. CHEMISTRY & YOU How do you think crystal-growing kits work? Use what you know about solubility and supersaturated solutions to explain your answer. Crystal-growing kits usually begin with a supersaturated solution. When a seed crystal is added to the solution, crystals rapidly begin to grow because the supersaturated solution contains more solute than is theoretically possible.

16.1 Properties of Solutions > 32 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Factors Affecting Solubility The effect of temperature on the solubility of gases in liquid solvents is opposite that of solids. The solubilities of most gases are greater in cold water than in hot. Temperature

16.1 Properties of Solutions > 33 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Factors Affecting Solubility Changes in pressure have little effect on the solubility of solids and liquids, but pressure strongly influences the solubility of gases. Gas solubility increases as the partial pressure of the gas above the solution increases. Pressure

16.1 Properties of Solutions > 34 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Factors Affecting Solubility Pressure Carbonated beverages are a good example. These drinks contain large amounts of carbon dioxide (CO 2 ) dissolved in water. Dissolved CO 2 makes the liquid fizz and your mouth tingle.

16.1 Properties of Solutions > 35 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Factors Affecting Solubility Pressure Carbonated beverages are a good example. The drinks are bottled under a high pressure of CO 2 gas, which forces larger amounts of the gas into solution.

16.1 Properties of Solutions > 36 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Factors Affecting Solubility Pressure Carbonated beverages are a good example. When the container is opened, the partial pressure of CO 2 above the liquid decreases. Immediately, bubbles of CO 2 form in the liquid and escape from the open bottle.

16.1 Properties of Solutions > 37 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Factors Affecting Solubility How is the partial pressure of carbon dioxide gas related to the solubility of CO 2 in a carbonated beverage? Pressure

16.1 Properties of Solutions > 38 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Factors Affecting Solubility How is the partial pressure of carbon dioxide gas related to the solubility of CO 2 in a carbonated beverage? The relationship is described by Henry’s law, which 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. Pressure

16.1 Properties of Solutions > 39 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Factors Affecting Solubility As the pressure of the gas above the liquid increases, the solubility of the gas increases. As the pressure of the gas decreases, the solubility of the gas decreases. Pressure

16.1 Properties of Solutions > 40 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Factors Affecting Solubility You can write the relationship in the form of an equation. = S1S1 P1P1 S2S2 P2P2 S 1 is the solubility of a gas at one pressure, P 1. S 2 is the solubility at another pressure, P 2. Pressure

16.1 Properties of Solutions > 41 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Chapter 16 Solutions 16.1 Properties of Solutions 16.2 Concentrations of Solutions 16.3 Colligative Properties of Solutions 16.4 Calculations Involving Colligative Properties

16.1 Properties of Solutions > 42 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.Molarity Molarity How do you calculate the molarity of a solution?

16.1 Properties of Solutions > 43 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.Molarity The concentration of a solution is a measure of the amount of solute that is dissolved in a given quantity of solvent. A solution that contains a relatively small amount of solute is a dilute solution. A concentrated solution contains a large amount of solute.

16.1 Properties of Solutions > 44 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.Molarity In chemistry, the most important unit of concentration is molarity. Molarity (M) is the number of moles of solute dissolved in one liter of solution. Molarity is also known as molar concentration.

16.1 Properties of Solutions > 45 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.Molarity The figure below illustrates the procedure for making a 0.5M, or 0.5-molar, solution. Add 0.5 mol of solute to a 1-L volumetric flask half filled with distilled water. Swirl the flask carefully to dissolve the solute. Fill the flask with water exactly to the 1-L mark.

16.1 Properties of Solutions > 46 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.Molarity To calculate the molarity of a solution, divide the number of moles of solute by the volume of the solution in liters. Molarity (M) = moles of solute liters of solution

16.1 Properties of Solutions > 47 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. How much water is required to make a 1.00M aqueous solution of NaCl, if 58.4 g of NaCl are dissolved? A.1.00 liter of water B.enough water to make 1.00 liter of solution C.1.00 kg of water D.100 mL of water

16.1 Properties of Solutions > 48 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. How much water is required to make a 1.00M aqueous solution of NaCl, if 58.4 g of NaCl are dissolved? A.1.00 liter of water B.enough water to make 1.00 liter of solution C.1.00 kg of water D.100 mL of water

16.1 Properties of Solutions > 49 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Making Dilutions What effect does dilution have on the amount of solute?

16.1 Properties of Solutions > 50 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Making Dilutions Both of these solutions contain the same amount of solute. You can tell by the color of solution (a) that it is more concentrated than solution (b). Solution (a) has the greater molarity. The more dilute solution (b) was made from solution (a) by adding more solvent.

16.1 Properties of Solutions > 51 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Making Dilutions Diluting a solution reduces the number of moles of solute per unit volume, but the total number of moles of solute in solution does not change. Moles of solute before dilution = Moles of solute after dilution

16.1 Properties of Solutions > 52 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Percent Solutions How do percent by volume and percent by mass differ?

16.1 Properties of Solutions > 53 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Percent Solutions Percent by volume of a solution is the ratio of the volume of solute to the volume of solution. Percent by volume (%(v/v)) =  100% volume of solution volume of solute

16.1 Properties of Solutions > 54 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Percent Solutions Percent by mass of a solution is the ratio of the mass of the solute to the mass of the solution. Percent by mass (%(m/m)) =  100% mass of solution mass of solute

16.1 Properties of Solutions > 55 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Chapter 16 Solutions 16.1 Properties of Solutions 16.2 Concentrations of Solutions 16.3 Colligative Properties of Solutions 16.4 Calculations Involving Colligative Properties

16.1 Properties of Solutions > 56 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. CHEMISTRY & YOU Why do you need salt to make ice cream? Ice-cream makers know that if you add rock salt to ice, the mixture freezes at a few degrees below 0°C.

16.1 Properties of Solutions > 57 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Describing Colligative Properties What are three colligative properties of solutions?

16.1 Properties of Solutions > 58 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Tea is not the same as pure water. Some of these differences in properties have little to do with the specific identity of the solute. Instead, they depend upon the mere presence of solute particles in the solution. Describing Colligative Properties

16.1 Properties of Solutions > 59 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. A colligative property is a property of solutions that depends only upon the number of solute particles, not upon their identity. Describing Colligative Properties

16.1 Properties of Solutions > 60 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Three important colligative properties of solutions are vapor-pressure lowering freezing-point depression boiling-point elevation Describing Colligative Properties

16.1 Properties of Solutions > 61 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Vapor pressure is the pressure exerted by a vapor that is in dynamic equilibrium with its liquid in a closed system. Describing Colligative Properties Vapor-Pressure Lowering

16.1 Properties of Solutions > 62 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Vapor pressure is the pressure exerted by a vapor that is in dynamic equilibrium with its liquid in a closed system. A solution that contains a solute that is nonvolatile (not easily vaporized) always has a lower vapor pressure than the pure solvent. Describing Colligative Properties Vapor-Pressure Lowering

16.1 Properties of Solutions > 63 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Equilibrium is established between the liquid and vapor in a pure solvent. Vapor-Pressure Lowering In a solution, solute particles reduce the number of solvent particles able to escape the liquid. Equilibrium is established at a lower vapor pressure. Describing Colligative Properties Higher vapor pressure Pure solventSolvent particle Lower vapor pressure Solution containing nonvolatile solute Solute particle

16.1 Properties of Solutions > 64 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Ionic solutes that dissociate have greater effects on vapor pressure than does a nondissociating solute. Describing Colligative Properties Vapor-Pressure Lowering

16.1 Properties of Solutions > 65 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Vapor-Pressure Lowering Ionic solutes that dissociate have greater effects on vapor pressure than does a nondissociating solute. Describing Colligative Properties Three moles of sodium chloride dissolved in water produce 6 mol of particles because each formula unit of NaCl dissociates into two ions.

16.1 Properties of Solutions > 66 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Vapor-Pressure Lowering Ionic solutes that dissociate have greater effects on vapor pressure than does a nondissociating solute. Describing Colligative Properties Three moles of calcium chloride dissolved in water produce 9 mol of particles because each formula unit of CaCl 2 dissociates into three ions.

16.1 Properties of Solutions > 67 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Vapor-Pressure Lowering Ionic solutes that dissociate have greater effects on vapor pressure than does a nondissociating solute. Describing Colligative Properties Three moles of glucose dissolved in water produce 3 mol of particles because glucose does not dissociate.

16.1 Properties of Solutions > 68 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Vapor-Pressure Lowering The decrease in a solution’s vapor pressure is proportional to the number of particles the solute makes in solution. Describing Colligative Properties

16.1 Properties of Solutions > 69 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Which solution has the lowest vapor pressure? Describing Colligative Properties Vapor-Pressure Lowering

16.1 Properties of Solutions > 70 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Which solution has the lowest vapor pressure? Describing Colligative Properties The vapor-pressure lowering caused by 0.1 mol of NaCl in 1000 g of water is twice that caused by 0.1 mol of glucose in the same quantity of water. Vapor-Pressure Lowering

16.1 Properties of Solutions > 71 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Which solution has the lowest vapor pressure? Describing Colligative Properties In the same way, 0.1 mol of CaCl 2 in 1000 g of water produces three times the vapor-pressure lowering as 0.1 mol of glucose in the same quantity of water. Vapor-Pressure Lowering

16.1 Properties of Solutions > 72 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. When a substance freezes, the particles of the solid take on an orderly pattern. Describing Colligative Properties Freezing-Point Depression

16.1 Properties of Solutions > 73 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. The presence of a solute in water disrupts the formation of this pattern. Describing Colligative Properties Freezing-Point Depression When a substance freezes, the particles of the solid take on an orderly pattern.

16.1 Properties of Solutions > 74 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. When a substance freezes, the particles of the solid take on an orderly pattern. The presence of a solute in water disrupts the formation of this pattern. As a result, more kinetic energy must be withdrawn from a solution than from the pure solvent to cause the solution to solidify. Describing Colligative Properties Freezing-Point Depression

16.1 Properties of Solutions > 75 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Describing Colligative Properties Freezing-Point Depression The freezing point of a solution is lower than the freezing point of the pure solvent.

16.1 Properties of Solutions > 76 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. The difference in temperature between the freezing point of a solution and the freezing point of the pure solvent is called the freezing-point depression. The freezing point of a solution is lower than the freezing point of the pure solvent. Describing Colligative Properties Freezing-Point Depression

16.1 Properties of Solutions > 77 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. The magnitude of the freezing-point depression is proportional to the number of solute particles dissolved in the solvent and does not depend upon their identity. Describing Colligative Properties Freezing-Point Depression Freezing-point depression is another colligative property.

16.1 Properties of Solutions > 78 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. The freezing-point depression of aqueous solutions plays an important role in helping keep travelers safe in cold, icy weather. Describing Colligative Properties Freezing-Point Depression

16.1 Properties of Solutions > 79 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. The freezing-point depression of aqueous solutions plays an important role in helping keep travelers safe in cold, icy weather. Describing Colligative Properties The truck spreads a layer of salt on the icy road to make the ice melt. The melted ice forms a solution with a lower freezing point than that of pure water. Freezing-Point Depression

16.1 Properties of Solutions > 80 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Describing Colligative Properties Boiling-Point Elevation The boiling point of a substance is the temperature at which the vapor pressure of the liquid phase equals atmospheric pressure.

16.1 Properties of Solutions > 81 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Boiling-Point Elevation The boiling point of a substance is the temperature at which the vapor pressure of the liquid phase equals atmospheric pressure. Adding a nonvolatile solute to a liquid solvent decreases the vapor pressure of the solvent. Describing Colligative Properties

16.1 Properties of Solutions > 82 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Boiling-Point Elevation The boiling point of a substance is the temperature at which the vapor pressure of the liquid phase equals the atmospheric pressure. Adding a nonvolatile solute to a liquid solvent decreases the vapor pressure of the solvent. Because of the decrease in vapor pressure, additional kinetic energy must be added to raise the vapor pressure of the liquid phase of the solution to atmospheric pressure and initiate boiling. Describing Colligative Properties

16.1 Properties of Solutions > 83 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. The boiling point of a solution is higher than the boiling point of the pure solvent. Describing Colligative Properties Boiling-Point Elevation

16.1 Properties of Solutions > 84 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. The boiling point of a solution is higher than the boiling point of the pure solvent. The difference in temperature between the boiling point of a solution and the boiling point of the pure solvent is the boiling-point elevation. Describing Colligative Properties Boiling-Point Elevation

16.1 Properties of Solutions > 85 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. The fluid circulating through a car’s cooling system is a solution of water and ethylene glycol, or antifreeze. The antifreeze doesn’t just lower the freezing point of the water in the cooling system. It also elevates the boiling point, which helps protect the engine from overheating in the summer. Describing Colligative Properties Boiling-Point Elevation

16.1 Properties of Solutions > 86 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Describing Colligative Properties Boiling-Point Elevation Boiling-point elevation is a colligative property; it depends on the concentration of particles, not on their identity.

16.1 Properties of Solutions > 87 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. The magnitude of the boiling-point elevation is proportional to the number of solute particles dissolved in the solvent. –The boiling point of water increases by 0.512°C for every mole of particles that the solute forms when dissolved in 1000 g of water. Describing Colligative Properties Boiling-Point Elevation Boiling-point elevation is a colligative property; it depends on the concentration of particles, not on their identity.

16.1 Properties of Solutions > 88 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. CHEMISTRY & YOU Solutes other than NaCl could be used to produce the same freezing- point depression in an ice-cream machine. What factors do you think make NaCl a good choice?

16.1 Properties of Solutions > 89 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. CHEMISTRY & YOU Solutes other than NaCl could be used to produce the same freezing- point depression in an ice-cream machine. What factors do you think make NaCl a good choice? NaCl, or rock salt, is readily available, inexpensive, and non- toxic. It is an ionic compound. It produces twice the freezing-point depression of a molecular solid such as sucrose, or table sugar.

16.1 Properties of Solutions > 90 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. You have 500 mL of 1M solutions of NaCl, Na 2 SO 4, Na 3 PO 4, and Al 2 (SO 4 ) 3. Which solution will have the highest boiling point? A.NaCl(aq) B.Na 2 SO 4 (aq) C.Na 3 PO 4 (aq) D.Al 2 (SO 4 ) 3 (aq)

16.1 Properties of Solutions > 91 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. You have 500 mL of 1M solutions of NaCl, Na 2 SO 4, Na 3 PO 4, and Al 2 (SO 4 ) 3. Which solution will have the highest boiling point? A.NaCl(aq) B.Na 2 SO 4 (aq) C.Na 3 PO 4 (aq) D.Al 2 (SO 4 ) 3 (aq)

16.1 Properties of Solutions > 92 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Key Concepts Colligative properties of solutions include vapor-pressure lowering, freezing-point depression, and boiling-point elevation.

16.1 Properties of Solutions > 93 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Glossary Terms colligative property: a property of a solution that depends only upon the number of solute particles, and not upon their identities; boiling- point elevation, freezing-point depression, and vapor-pressure lowering are colligative properties

16.1 Properties of Solutions > 94 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Glossary Terms freezing-point depression: the difference in temperature between the freezing point of a solution and the freezing point of the pure solvent boiling-point elevation: the difference in temperature between the boiling point of a solution and the boiling point of the pure solvent

16.1 Properties of Solutions > 95 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Solubility, miscibility, concentration, and colligative properties are used to describe and characterize solutions. BIG IDEA The Mole and Quantifying Matter

16.1 Properties of Solutions > 96 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. END OF 16.3