Solutions and Solutions and other Mixturesother Mixtures

Ch 20.1Ch 20.1

MixtureMixtureA combination of more than A combination of more than one pure substances one pure substances physically combined.physically combined.

Two Types:Two Types:

HomogeneousHomogeneousSame throughoutSame throughout

HeterogeneousHeterogeneousDifferent throughoutDifferent throughout

Homogeneous MixturesHomogeneous Mixtures

SolutionSolution::a homogeneous mixture of 2 substances a homogeneous mixture of 2 substances

uniformly spread throughout a medium.uniformly spread throughout a medium.Most consist of a solid dissolved in a liquidMost consist of a solid dissolved in a liquidMade from two partsMade from two parts

Solution Parts:Solution Parts:Solvent:Solvent: substance that dissolves a substance that dissolves a solute.solute.

Greater quantity (ex. water)Greater quantity (ex. water)Solute:Solute: substance that dissolves in substance that dissolves in a solution.a solution.Lesser quantity (ex. Salt, sugar)Lesser quantity (ex. Salt, sugar)

Dissolving ProcessDissolving Process1.Dissociation:1.Dissociation:

The separation of solute ions The separation of solute ions

away from the salt crystal away from the salt crystal (only ionic compound solutes)(only ionic compound solutes)

2. Solvation:2. Solvation:

The attraction of solvent The attraction of solvent particles to solute particles. They will then particles to solute particles. They will then surround the solute particles. surround the solute particles.

(called hydration when water is the solvent)(called hydration when water is the solvent)

Dissociation of ions

Solvation/hydration

PolarityPolarity

Property of a molecule caused by an Property of a molecule caused by an unsymmetrical charge distribution.unsymmetrical charge distribution.Molecule has a (+) and (Molecule has a (+) and (--) end) endWater is very polar, and is considered the Water is very polar, and is considered the universal solventuniversal solvent

Most solutions use water as the solventMost solutions use water as the solventSalts behave like a polar substances because they are Salts behave like a polar substances because they are electrolyteselectrolytes

SolventSolvent--Solute CombinationsSolute Combinations

““LikeLike”” dissolves in dissolves in ““likelike””Polar solutes dissolves in polar solventsPolar solutes dissolves in polar solventsNonpolarNonpolar solutes dissolves in non polar solutes dissolves in non polar solventssolvents

Polar solvent

will attract

a polar solute

Nonpolar

solute

will not dissolve in polar solvent

Solid, liquid, and Gas SolutionsSolid, liquid, and Gas Solutions

All mixtures of gases are solutionsAll mixtures of gases are solutionsMost metal alloys are solutions Most metal alloys are solutions (a mixture made from two or more solids)(a mixture made from two or more solids)Mixtures between two liquids are classified by Mixtures between two liquids are classified by their miscibilitytheir miscibility

Miscible liquids dissolve and form solutionsMiscible liquids dissolve and form solutionsimmiscible liquids wonimmiscible liquids won’’t dissolve t dissolve

Solutions PropertiesSolutions Properties

Particles dissolve, they donParticles dissolve, they don’’t settle out.t settle out.Light can pass through liquid Light can pass through liquid solutionssolutionsHomogeneous mixtures (uniform)Homogeneous mixtures (uniform)

Solution EquilibriumSolution Equilibrium

Solution Equilibrium Solution Equilibrium –– rate of dissociating ions rate of dissociating ions equals the rate that the ions resurface on the salt equals the rate that the ions resurface on the salt crystal .crystal .

Solution EquilibriumSolution Equilibrium

UnsaturatedUnsaturated-- A solution holding less solute than A solution holding less solute than the solution can dissolve.the solution can dissolve.Saturated SolutionSaturated Solution-- A solution dissolving the A solution dissolving the maximum amount of solute particles. maximum amount of solute particles. (in equilibrium)(in equilibrium)SupersaturatedSupersaturated-- An unstable solution containing An unstable solution containing more solute than the saturation point.more solute than the saturation point.

Heat up a solution and dissolve more soluteHeat up a solution and dissolve more soluteThen slowly bring down to a cooler temperatureThen slowly bring down to a cooler temperature

When you add more solute particles, the whole solution

will

precipitate out and solidify.

Solubility Solubility Measures the amount of solute that will dissolve in Measures the amount of solute that will dissolve in a given amount of solvent at specific temperatures a given amount of solvent at specific temperatures Saturated amountSaturated amount

Dissolving EffectsDissolving Effects1.1.

Increase Surface AreaIncrease Surface Area--

making more solute particles making more solute particles

exposed to the solvent.exposed to the solvent.Breaking down into smaller piecesBreaking down into smaller pieces

2.2.

StirringStirring--

Increases surface areaIncreases surface area

3.3.

Changing TemperatureChanging Temperature--

heating makes solvent heating makes solvent

molecules move quicker (more kinetic energy)molecules move quicker (more kinetic energy)4.4.

Already dissolved solute particles will slow down Already dissolved solute particles will slow down other solute from dissolving.other solute from dissolving.

5.5.

Pressure affects how well Pressure affects how well gasesgases

stay dissolved. stay dissolved.

Gases stay dissolved at higher pressures. (no affect Gases stay dissolved at higher pressures. (no affect on solid solute) on solid solute)

Carbonation bubbles form when the pressure is decreased

when opening a soda bottle.

Dissolving EffectsDissolving Effects

Enthalpy (heat) of Solution (Enthalpy (heat) of Solution (∆∆HHsol))Energy transfer during the dissolving process.Energy transfer during the dissolving process.

Most solids become more soluble with rising temps. Most solids become more soluble with rising temps. Positive Positive ∆∆HHsol (endothermic)Gases become more soluble with colder temperatures. Gases become more soluble with colder temperatures. Negative Negative ∆∆HHsol (exothermic)

Precipitation ReactionsPrecipitation Reactions

Reaction between two solutions (double displacement)Reaction between two solutions (double displacement)The ions in solution rearrange and interact with each The ions in solution rearrange and interact with each other.other.The result will form an insoluble precipitate. The result will form an insoluble precipitate.

CONCENTRATIONCONCENTRATIONThe quantity of The quantity of solutesolute dissolved dissolved in a given quantity of in a given quantity of solutionsolution..Adding water (solvent) will Adding water (solvent) will dilutedilute your concentration.your concentration.(decreasing the concentration)(decreasing the concentration)

CONCENTRATIONCONCENTRATIONMolarity (M) is measurement of Molarity (M) is measurement of concentration. (Molar)concentration. (Molar)Molarity is the number of Molarity is the number of moles moles of solute of solute dissolved in one dissolved in one literliter of solution.of solution.M= M= moles of solutemoles of solute

liter of solutionliter of solutionM=n/VM=n/VUnits = M or mol/LUnits = M or mol/L

Molarity ExampleMolarity Example

How many moles of solute are present in 1.5 L How many moles of solute are present in 1.5 L of 0.20 M NaCl solution?of 0.20 M NaCl solution?M = M = moles of NaClmoles of NaCl 0.20M = 0.20M = molesmoles

liter solutionliter solution

1.5 L1.5 LMoles = 0.30 moles of NaCl needed to dissolveMoles = 0.30 moles of NaCl needed to dissolve

Molarity ExampleMolarity Example

How many How many gramsgrams of Copper II chloride should be of Copper II chloride should be used to prepare 25.0 mL of a 0.40 M solution? used to prepare 25.0 mL of a 0.40 M solution? M = M = moles of CuClmoles of CuCl22 .40 M = .40 M = molesmoles

liter solutionliter solution

.0250 L.0250 LMoles = .010 moles of CuClMoles = .010 moles of CuCl22 needed to dissolveneeded to dissolveNow convert moles to gramsNow convert moles to grams.010 moles x .010 moles x 134 grams CuCl134 grams CuCl22==

1 mole CuCl1 mole CuCl221.3 grams

CONCENTRATIONCONCENTRATIONPercent Concentration is another Percent Concentration is another measurement of concentration.measurement of concentration.% = (solute/solution) x 100% = (solute/solution) x 100

Changing ConcentrationChanging Concentration

Diluting Concentrations:Diluting Concentrations:MM11VV11=M=M22VV22

How much water is needed to dilute a 2.0 M How much water is needed to dilute a 2.0 M solution of HCl with a volume of 120 ml, to a solution of HCl with a volume of 120 ml, to a 0.50 molar solution?0.50 molar solution?2.0 M x 120 ml = .50M x V22.0 M x 120 ml = .50M x V2V2= 480 mlV2= 480 mlSo 360 ml of water is needed So 360 ml of water is needed

Heterogeneous MixturesHeterogeneous Mixtures

Ch 20.2Ch 20.2

Two Types:Two Types:1.1.

SuspensionSuspension

2.2. Colloids Colloids

SuspensionsSuspensionsHeterogeneous mixtureHeterogeneous mixturea mixture that looks uniform when a mixture that looks uniform when shaken.shaken.Particles Settle out, because the two Particles Settle out, because the two parts of mixture repel each other.parts of mixture repel each other.Label says to need to shake or stirLabel says to need to shake or stirEx. orange juice with pulp, salad dressingEx. orange juice with pulp, salad dressing

ColloidColloidIntermediate between suspensions and Intermediate between suspensions and solutionssolutionsa mixture of very tiny particles that are a mixture of very tiny particles that are scattered/dispersed in another substance.scattered/dispersed in another substance.Two parts present (you only see one)Two parts present (you only see one)Particles do Particles do notnot settle out or dissolvesettle out or dissolve3 major types3 major types

1. Aerosols1. AerosolsLiquids or solids particles scattered in Liquids or solids particles scattered in a gasa gasEx. Fog, smoke, hair spray, insect Ex. Fog, smoke, hair spray, insect sprayspray

2. Foam2. FoamMixture where gases are scattered in a Mixture where gases are scattered in a solid or liquidsolid or liquidEx. Whipped cream, shaving Ex. Whipped cream, shaving cream, gelscream, gels

3. Emulsion (most common)3. Emulsion (most common)a mixture where a liquid is scattered a mixture where a liquid is scattered through out another liquid or solidthrough out another liquid or solidUsually homogenized (one phase)Usually homogenized (one phase)Contain emulsifying agentContain emulsifying agent

Substance with polar and nonpolar endSubstance with polar and nonpolar endEx. Soap, detergent, eggEx. Soap, detergent, egg

Ex. mayonnaise, cheese, glueEx. mayonnaise, cheese, glue

SolutionsSolutions ColloidsColloids

(emulsion)(emulsion)

SuspensionSuspension

DonDon’’t Settle outt Settle out

(dissolve)(dissolve)

DonDon’’t Settle outt Settle outDonDon’’t dissolvet dissolve

Do Settle out and can be Do Settle out and can be filteredfiltered

HomogeneousHomogeneous

(parts both polar or both (parts both polar or both nonpolarnonpolar) )

Intermediate between Intermediate between solutions and suspensionssolutions and suspensions(polar and (polar and nonpolarnonpolar

end)end)

HeterogeneousHeterogeneous(one part polar and one part (one part polar and one part

nonpolarnonpolar))DoesnDoesn’’t Scatter Lightt Scatter Light

(transparent)(transparent)

Does Scatter LightDoes Scatter Light(opaque)(opaque)

(Tyndall Effect occurs)(Tyndall Effect occurs)

Can see two phasesCan see two phases(Tyndall Effect occurs when (Tyndall Effect occurs when

shaken)shaken)

Affected by colligative Affected by colligative propertiesproperties

NotNot

affected by colligative affected by colligative propertiesproperties

NotNot

affected by colligative affected by colligative propertiesproperties

LETS COMPARELETS COMPARE

Colligative Colligative PropertiesProperties

Ch 21.1Ch 21.1

ColligativeColligative

PropertiesProperties

The properties of The properties of solutionssolutions that are that are affected by the amount of solute affected by the amount of solute added to solution.added to solution.These properties are different than These properties are different than those of the pure solvent.those of the pure solvent.Four PropertiesFour Properties

1. Vapor Pressure1. Vapor Pressure

The presence of nonvolatile solute at a The presence of nonvolatile solute at a specific concentration, lowers the vapor specific concentration, lowers the vapor pressure of a solution.pressure of a solution.Solute particles are decreasing the Solute particles are decreasing the opportunity for solvent particles to opportunity for solvent particles to evaporate lowering the vapor pressure.evaporate lowering the vapor pressure.This property allows scientist to separate This property allows scientist to separate the parts petroleum by distillation.the parts petroleum by distillation.

2. Boiling Point Elevation2. Boiling Point Elevation

The presence of nonvolatile solute The presence of nonvolatile solute particles raises the boiling point. particles raises the boiling point. Adding salt to boiling water Adding salt to boiling water prevents you from over cooking prevents you from over cooking the pasta.the pasta.

3. Freezing Point Depression3. Freezing Point Depression

The presence of nonvolatile solute The presence of nonvolatile solute particles lowers the freezing point. particles lowers the freezing point. Calcium chloride is added to streets Calcium chloride is added to streets and sidewalks to deice.and sidewalks to deice.Sodium chloride is added to ice to Sodium chloride is added to ice to maintain lower temperatures while maintain lower temperatures while freezing homemadefreezing homemade

Ch21.2Ch21.2 4. Osmosis4. Osmosis

The diffusion of solvent through a The diffusion of solvent through a membrane from an area of higher membrane from an area of higher solvent concentration to lower solvent concentration to lower concentration. concentration. SemipermeableSemipermeable MembraneMembrane--barrier allowing solvent through, barrier allowing solvent through, but block larger solute particles.but block larger solute particles.

High concentration

4. Osmosis4. Osmosis

Osmotic PressureOsmotic Pressure-- Pressure Pressure developed across a membrane that developed across a membrane that allows the diffusion of solvent allows the diffusion of solvent particles to reach equilibrium. particles to reach equilibrium. Chemistry behind your kidneys and Chemistry behind your kidneys and making picklesmaking pickles

Ch23.1 ElectrolytesCh23.1 ElectrolytesAcids, bases, and salts when dissolved in Acids, bases, and salts when dissolved in water, will conduct electricity.water, will conduct electricity.Substances will ionize (acids) or dissociate Substances will ionize (acids) or dissociate (bases, salts)(bases, salts)

Arrhenius TheoryArrhenius TheoryAcid aqueous solutions release Acid aqueous solutions release hydrogen ions (Hhydrogen ions (H++) ) Base aqueous solutions release Base aqueous solutions release hydroxide ions (OHhydroxide ions (OH--))

HCl HCl →→ HH++ + Cl+ Cl--

NaOH NaOH →→ NaNa++ + OH+ OH--

Definition was too narrowwas too narrow

BrBrøønstednsted--Lowry TheoryLowry Theory

In a chemical reaction, any In a chemical reaction, any substance that substance that donatesdonates a proton a proton (hydrogen ion) is an (hydrogen ion) is an acidacid, and any , and any substance that substance that acceptsaccepts a proton a proton (hydrogen ion) is a (hydrogen ion) is a basebase..Acid + base Acid + base →→ conjugate acid + conjugate baseconjugate acid + conjugate base

Acid forms into CBAcid forms into CBBase forms into CABase forms into CA

BrBrøønstednsted--Lowry TheoryLowry TheoryConjugate acidConjugate acid ––the particle or the particle or substance obtained after a base has substance obtained after a base has gained a proton (hydrogen)gained a proton (hydrogen)Conjugate baseConjugate base ––the particle or the particle or substance obtained after an acid substance obtained after an acid has donated a proton (hydrogen)has donated a proton (hydrogen)HCl + HHCl + H22O O →→ HH33OO++ + Cl+ Cl--acid base acid base C.A. C.B.

Hydronium IonHydronium Ion

An ion formed when a free HAn ion formed when a free H++ forms with forms with water to form an Hwater to form an H33OO++

Hydrated protonHydrated protonHydrogen ions will not stay free for long Hydrogen ions will not stay free for long and will bond with water molecules in and will bond with water molecules in solutionsolution

↔

↔

You PracticeYou PracticeNHNH33 + H+ H22O O ↔↔ NHNH44

++ + OH+ OH--

base acid base acid HNOHNO33 + NaOH + NaOH →→ HH22O + NaNOO + NaNO33acid base acid base NaHCONaHCO33 + HCl + HCl →→ NaCl + HNaCl + H22COCO33base acid base acid

C.A. C.B.

C.A. C.B.

C.B. C.A.

Acid PropertiesAcid PropertiesSour tasteSour tastefruits (citric acid)fruits (citric acid)Vinegar (acetic acid)Vinegar (acetic acid)Will burn if not dilutedWill burn if not dilutedNeutralize basesNeutralize basesNonmetals will form acids with hydrogenNonmetals will form acids with hydrogenex HCl, Hex HCl, H22SOSO44

OUCH! Don’t pick your scabs

Base PropertiesBase PropertiesBitter tasteBitter tasteSlippery feelSlippery feelHousehold cleanersHousehold cleanersAlso dangerous if not dilutedAlso dangerous if not dilutedNeutralize acidsNeutralize acidsAlso known as alkaline solutionsAlso known as alkaline solutionsMetals reacting with hydroxide will form bases ex Metals reacting with hydroxide will form bases ex NaOH, KOH, Ba(OH)NaOH, KOH, Ba(OH)22

Naming Acids Naming Acids Binary Binary –– contain two elementscontain two elementsStep 1 Step 1 –– add prefix hydroadd prefix hydro--Step 2 Step 2 –– add stem elementadd stem element--Step 3 Step 3 –– add add --icic ending and the word acidending and the word acidEX. HCl is hydrochloric acidEX. HCl is hydrochloric acidName the following HF, HName the following HF, H33PPWrite the formula of Write the formula of hydrosulfurichydrosulfuric AcidAcid

Naming Acids Naming Acids TernaryTernary-- contains three elementscontains three elementsStep 1 Step 1 –– identify polyatomic ion in formulaidentify polyatomic ion in formulaStep 2 Step 2 –– add appropriate suffixadd appropriate suffix

for ions that end in for ions that end in --ate add ate add ––icic endingendingFor ions that end in For ions that end in ––iteite add add --ousous endingendingEX. HEX. H22SOSO44 is sulfuric acidis sulfuric acidEX. HEX. H22SOSO33 is sulfurous acidis sulfurous acidName HNOName HNO33 and HNOand HNO22

Write the formula of phosphoric AcidWrite the formula of phosphoric Acid

Naming BasesNaming BasesYou already know how!!!You already know how!!!Ex. NaOH = sodium HydroxideEx. NaOH = sodium HydroxideEx. Ba(OH)Ex. Ba(OH)22 = barium hydroxide= barium hydroxide

Amphoteric Amphoteric

A substance having the ability A substance having the ability to act as an acid or a baseto act as an acid or a baseWater is an exampleWater is an exampleHCl (proton donor) + HHCl (proton donor) + H22O (base) O (base) ------> H> H3300++ + + ClCl--

NHNH3 3 (proton acceptor) + H(proton acceptor) + H22O (acid) O (acid) ------> NH> NH44++ + OH+ OH--

Acidic AnhydridesAcidic AnhydridesAcidic anhydride remove waterAcidic anhydride remove waterAcid rain is an exampleAcid rain is an exampleCaused by the burning of fossil fuels. (producing Caused by the burning of fossil fuels. (producing NONOxx and and SOSO22 gases) gases) NONOxx and SOand SO22 reacts with water vapor in atmosphere to reacts with water vapor in atmosphere to form acids.form acids.

Acid RainAcid RainPrecipitation that has an unusually Precipitation that has an unusually high concentration of high concentration of sulfuricsulfuric and and nitricnitric acidsacids resulting from pollution in resulting from pollution in air.air.Normal rain fall has pH of 5.3 due to Normal rain fall has pH of 5.3 due to natural carbonic acid forming in the natural carbonic acid forming in the atmosphereatmosphereUS cities average between 4US cities average between 4--55

Strong Acids will completely ionize in water

Ch23.2 Neutralization ReactionsCh23.2 Neutralization Reactions

You can neutralize a base with an acid You can neutralize a base with an acid or an acid with a base. or an acid with a base. The result will form water molecules The result will form water molecules and salts.and salts.NaOH + HCl NaOH + HCl →→ NaCl + HNaCl + H2200

24.1 Measuring 24.1 Measuring AcidsAcids

pH pH the measure of the hydronium the measure of the hydronium ion concentration and acidityion concentration and acidityrange 0 range 0 –– 14140 acidic,0 acidic, 7 neutral, 7 neutral, 14 basic14 basic

Very low pH

Very high pH

Swimming anyone?

Measuring AcidsMeasuring AcidsConcentration read by powers of Concentration read by powers of ten. Logarithms used to calculate. ten. Logarithms used to calculate. pH = pH = --log [Hlog [H33OO++]]Concentration = 10Concentration = 10--pHpH

If a substance has a HIf a substance has a H33OO++

concentration of 10 concentration of 10 --99 its pH is 9.its pH is 9.

Measuring AcidsMeasuring AcidsWhat is the pH of a sample with a hydronium What is the pH of a sample with a hydronium concentration of 6.59 x 10concentration of 6.59 x 10--1010 M?M?pH = pH = --log [6.59 x 10log [6.59 x 10--1010

M] = M] =

What is the hydronium concentration of a What is the hydronium concentration of a solution with a pH of 2.523?solution with a pH of 2.523?concentration = 10concentration = 10--2.5232.523= =

9.18

3.00 x 10-3 M

Measuring AcidsMeasuring AcidspOH pOH the measure of the hydroxide ion the measure of the hydroxide ion concentration and how basicconcentration and how basicpOH = pOH = --log [ OHlog [ OH--]]pH + pOH = 14pH + pOH = 14

Measuring AcidsMeasuring AcidsWhat is the pH of a solution with a hydroxide What is the pH of a solution with a hydroxide concentration of 2.93 x 10concentration of 2.93 x 10--22M?M?pOH = pOH = --log [2.93 x 10log [2.93 x 10--22M] = M] =

pH = 14 pH = 14 ––

1.53 = 1.53 =

1.53

12.47

AquariumsAquariums

Scaled down models of natural ecosystems Scaled down models of natural ecosystems for different animals or plants.for different animals or plants.Much more sensitive to changes in Much more sensitive to changes in temperature, pH, and any other substance temperature, pH, and any other substance that can get into the system.that can get into the system.Buffers are used to stabilize the pH of the Buffers are used to stabilize the pH of the water system.water system.

IndicatorIndicatora compound that can reversibly change a compound that can reversibly change color depending on the concentration of color depending on the concentration of HH33OO++ ions.ions.Used to measure pHUsed to measure pHSolution being tested must be colorless to Solution being tested must be colorless to see an accurate color change. see an accurate color change.

TitrationTitration

Process of finding the Process of finding the concentration of an concentration of an unknown solution by unknown solution by neutralizing it with a neutralizing it with a standard solutionstandard solution..When the solution with an When the solution with an indicator changes color the indicator changes color the end pointend point of the of the neutralization reaction neutralization reaction occurs.occurs.The concentration then can The concentration then can be calculated.be calculated.

Titration Example ProblemTitration Example Problem

What is the molarity of 125. 0 ml of HCl solution if it is What is the molarity of 125. 0 ml of HCl solution if it is neutralized by 160 ml of 5.00 M NaOH?neutralized by 160 ml of 5.00 M NaOH?HCl + NaOH HCl + NaOH →→ NaCl + HNaCl + H22

OOmoles = molarity x volumemoles = molarity x volume5.00 M NaOH x 0.160 L NaOH = 0.800 moles NaOH5.00 M NaOH x 0.160 L NaOH = 0.800 moles NaOHEqual moles of HCl and NaOH are reacting, then Equal moles of HCl and NaOH are reacting, then 0.800 moles of HCl were also neutralized 0.800 moles of HCl were also neutralized M = 0.800 moles HCl/ 0.125 L HCl= 6.4 M of HClM = 0.800 moles HCl/ 0.125 L HCl= 6.4 M of HCl