SolutionsSolutions

Objectives/Warm-UpObjectives/Warm-Up

• SWBAT describe dilute, concentrated, SWBAT describe dilute, concentrated, saturated, unsaturated, and saturated, unsaturated, and supersaturated solutions.supersaturated solutions.

• What do the terms “concentrated” What do the terms “concentrated” and “dilute” mean to you?and “dilute” mean to you?

Objective/Warm-UpObjective/Warm-Up

• SWBAT describe solutions and be SWBAT describe solutions and be able to complete molarity and able to complete molarity and dilution calcualtions.dilution calcualtions.

• How do we know if something is How do we know if something is more or less concentrated or dilute? more or less concentrated or dilute? How could we quantify (measure) How could we quantify (measure) concentration?concentration?

ConcentratedConcentrated

• Look at the two bottles of laundry Look at the two bottles of laundry detergent.detergent.

• Why is one bottle smaller than the Why is one bottle smaller than the other?other?

• What does it mean that the smaller What does it mean that the smaller bottle is more “concentrated”?bottle is more “concentrated”?

• What is the difference between the What is the difference between the two laundry detergents?two laundry detergents?

• SoluteSolute-what is being -what is being dissolveddissolved

• SolventSolvent-what the solute -what the solute is being dissolved inis being dissolved in

• SolutionSolution-the mixture of -the mixture of solute and solventsolute and solvent

Making Kool-AidMaking Kool-Aid

• When you make Kool-Aid, what is the When you make Kool-Aid, what is the solute?solute?

• What is the solvent?What is the solvent?

• What is the solution?What is the solution?

Making Kool-AidMaking Kool-Aid

• If you make a concentrated solution of If you make a concentrated solution of Kool-Aid.Kool-Aid.– This solution has too much___________.This solution has too much___________.

• If you make a dilute solution of Kool-If you make a dilute solution of Kool-Aid.Aid.– This solution has too much ____________.This solution has too much ____________.

• How can we use the concentrated How can we use the concentrated solution of Kool-Aid to make a more solution of Kool-Aid to make a more dilute solution of Kool-Aid?dilute solution of Kool-Aid?

solute

solvent

Saturated SolutionsSaturated Solutions

• Is there a limit to how much Kool-Aid or Is there a limit to how much Kool-Aid or sugar we can dissolve in water?sugar we can dissolve in water?

• What happens when we reach that What happens when we reach that limit?limit?

• What can we do to the solution to What can we do to the solution to make more sugar dissolve?make more sugar dissolve?

• When we can add no more solute to a When we can add no more solute to a solution, the solution is SATURATED.solution, the solution is SATURATED.

Objective/Warm-UpObjective/Warm-Up

• SWBAT describe solutions.SWBAT describe solutions.

• What is a saturated solution?What is a saturated solution?

Ch. 15-SolutionsCh. 15-SolutionsEssential QuestionsEssential Questions

•What makes up a solution?What makes up a solution?

•What are some different types of What are some different types of solutions?solutions?

•How can I make a solution?How can I make a solution?

•What factors affect solubility?What factors affect solubility?

•How can I measure or calculate the How can I measure or calculate the solubility or concentration of a solubility or concentration of a solution?solution?

SupersaturatedSupersaturated

• http://www.pbs.org/kcet/wiredscience/video/http://www.pbs.org/kcet/wiredscience/video/259-dr_schrempp_s_chem_lab.html259-dr_schrempp_s_chem_lab.html

• Watch the demonstration of the Watch the demonstration of the crystallization of a supersaturated solution.crystallization of a supersaturated solution.

• SupersaturatedSupersaturated means that more solute is means that more solute is dissolved in the solution than should be dissolved in the solution than should be able to dissolve at that temperature.able to dissolve at that temperature.

• To make a supersaturated solution, heat To make a supersaturated solution, heat the solution to get the solute to dissolve, the solution to get the solute to dissolve, then let it cool.then let it cool.

Solubility CurvesSolubility Curves

Objective/Warm-UpObjective/Warm-Up

• SWBAT describe solutions and be SWBAT describe solutions and be able to complete molarity and able to complete molarity and dilution calcualtions.dilution calcualtions.

• How do we know if something is How do we know if something is more or less concentrated or dilute? more or less concentrated or dilute? How could we quantify (measure) How could we quantify (measure) concentration?concentration?

How do we measure How do we measure concentration?concentration?

• MOLARITYMOLARITY

• M = moles solute/Liters of solutionM = moles solute/Liters of solution

Showing saturated solutionsShowing saturated solutions

• http://www.wwnorton.com/college/chhttp://www.wwnorton.com/college/chemistry/gilbert2/tutorials/interface.asemistry/gilbert2/tutorials/interface.asp?chapter=chapter_04&folder=saturp?chapter=chapter_04&folder=saturated_solutionsated_solutions

Thinking back…Thinking back…

• What is the difference between What is the difference between homogeneous and heterogeneous homogeneous and heterogeneous mixtures?mixtures?

What is a solution?What is a solution?

• A homogeneous mixture of two or A homogeneous mixture of two or more substances.more substances.

Examples of Solutions…Examples of Solutions…

What are the solute and solvent for each of What are the solute and solvent for each of these solutions?these solutions?

• Kool-aidKool-aid

• TeaTea

• AirAir

• SodaSoda

• BrassBrass

• SteelSteel

Review from Yesterday…Review from Yesterday…

• Solubility: “Like Dissolves Like”Solubility: “Like Dissolves Like”

• Fill out chart.Fill out chart.

Objective/Warm-UpObjective/Warm-Up

• SWBAT solve dilution problems. SWBAT solve dilution problems.

• How many grams of NaCl are needed How many grams of NaCl are needed to make 250 mL of a 0.100 M to make 250 mL of a 0.100 M solution?solution?

• Volume-Measuring Devices

buret

graduated cylinder

volumetric flask

pipette

How do we make How do we make solutions for the lab?solutions for the lab?

• Using the following materials, predict how Using the following materials, predict how they might be used to make solutions they might be used to make solutions with a particular molarity: balance, wash with a particular molarity: balance, wash bottle, distilled water, volumetric flask.bottle, distilled water, volumetric flask.

• Procedure:Procedure:1.1. Weigh solid.Weigh solid.

2.2. Put some distilled water in volumetric flask.Put some distilled water in volumetric flask.

3.3. Add solid and stir.Add solid and stir.

4.4. Fill water to line, mix completely.Fill water to line, mix completely.

a) To make a 0.5-molar (0.5M) solution, first add 0.5 mol of solute to a 1-L volumetric flask half filled with distilled water.

b) Swirl the flask carefully to dissolve the solute.

c) Fill the flask with water exactly to the 1-L mark.

• http://cwx.prenhall.com/petrucci/medhttp://cwx.prenhall.com/petrucci/medialib/media_portfolio/text_images/013ialib/media_portfolio/text_images/013_SOLUTFROMSOL.MOV_SOLUTFROMSOL.MOV

Oops, It’s too concentrated!Oops, It’s too concentrated!

• Our solution is too concentrated. Our solution is too concentrated. How can we dilute the solution so How can we dilute the solution so that it is less concentrated?that it is less concentrated?

DilutionDilution

• MM11VV11=M=M22VV22

• Because… the moles stay the same!Because… the moles stay the same!

Making a Dilute Solution

a) To prepare 100 ml of 0.40M MgSO4 from a stock solution of 2.0M MgSO4, a student first measures 20 mL of the stock solution with a 20-mL pipet.

b) She then transfers the 20 mL to a 100-mL volumetric flask.

c) Finally she carefully adds water to the mark to make 100 mL of solution.

Dilution Practice ProblemsDilution Practice Problems

1. To make a 1.00M aqueous solution of NaCl, 58.4 g of NaCl are dissolved in

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.

16.2 Review

2. What mass of sodium iodide (NaI) is contained in 250 mL of a 0.500M solution?

a) 150 gb) 75.0 gc) 18.7 gd) 0.50 g 18.7g

mol

149.89g(0.125mol)

NaI0.125_mol_x0.250L

x0.5M

3. Diluting a solution does NOT change which of the following?

a) concentrationb) volumec) milliliters of solventd) moles of solute

Objective/Warm-UpObjective/Warm-Up

• SWBAT calculate molality and SWBAT calculate molality and describe types of solutions.describe types of solutions.

• If 10.0 grams of NaOH are dissolved If 10.0 grams of NaOH are dissolved in enough solvent to make 100 mL of in enough solvent to make 100 mL of solution, what is the molarity of the solution, what is the molarity of the solution?solution?

Types of SolutionsTypes of Solutions

•AlloysAlloys-mixture of two or more metals-mixture of two or more metals

•Miscible-Miscible- mixture of two liquids that mixture of two liquids that can mix in any proportioncan mix in any proportion

• ImmiscibleImmiscible- liquids that cannot mix - liquids that cannot mix in any proportionin any proportion

•AqueousAqueous- solutions with water as a - solutions with water as a solventsolvent

Types of Aqueous solutionsTypes of Aqueous solutions

•ElectrolytesElectrolytes-conduct electricity in -conduct electricity in water, made primarily with ionic water, made primarily with ionic compoundscompounds

•Non-electrolytesNon-electrolytes-do not conduct -do not conduct electricity in water, made primarily electricity in water, made primarily with covalent compoundswith covalent compounds

MolalityMolality

• Molality: Molality: m m =moles solute/kg solvent=moles solute/kg solvent

• How is molality different than How is molality different than molarity? molarity?

• How would these differences affect How would these differences affect how to make a solution based on how to make a solution based on molality as opposed to molarity?molality as opposed to molarity?

• To make a 0.500m solution of NaCl, use a balance to measure 1.000 kg of water and add 0.500 mol (29.3 g) of NaCl.

Practice CalculationsPractice Calculations

Objective/Warm-UpObjective/Warm-Up

• SWBAT solve molarity and molality SWBAT solve molarity and molality problems. problems.

• How many grams of FeClHow many grams of FeCl33 are needed are needed to make 50 mL of a 0.170 M solution?to make 50 mL of a 0.170 M solution?

Reading Article/DiscussionReading Article/Discussion

• Read the Article from the Washington Read the Article from the Washington Post.Post.

• In your group, create a chart/table/or In your group, create a chart/table/or graphic organizer (such as a Venn graphic organizer (such as a Venn Diagram, concept map or web) Diagram, concept map or web) describing how to get out different describing how to get out different types of stains (oily, water-based, types of stains (oily, water-based, combination stains, carbohydrates, combination stains, carbohydrates, proteins, food pigments, wine stains)proteins, food pigments, wine stains)

Why?Why?

• Write a 1-2 sentence summary Write a 1-2 sentence summary explain how and/or why different explain how and/or why different cleaning methods are needed for cleaning methods are needed for different stains.different stains.