Ácidos,bases,soluciones

8/13/2019 cidos,bases,soluciones

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Chapter 3Chapter 3

Acids, Bases, andAcids, Bases, and

SolutionsSolutions

Chapter 3 ProjectChapter 3 Project

Turn to page LTurn to page L--79 in your79 in yourtextbook and start thetextbook and start the

chapter 3 project.chapter 3 project.

Discover ActivityDiscover Activity

Turn to page 80Turn to page 80--L in yourL in your

textbooktextbook

Solutions and SuspensionsSolutions and Suspensions

Suspension:Suspension:A mixture inA mixture in

which particles can be seenwhich particles can be seen

and easily separated byand easily separated by

settling or filtrationsettling or filtration

Solution:Solution:A wellA well--mixedmixedmixturemixture

Cannot see individualCannot see individualparticlesparticles

Can usually be separatedCan usually be separatedby evaporationby evaporation

Solvent vs. SoluteSolvent vs. Solute

Solvent:Solvent: The part of theThe part of the

solution present in thesolution present in the

largest amountlargest amount It dissolvesIt dissolves

the other substancethe other substance


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Solute:Solute: The part of theThe part of thesolution present in thesolution present in thesmaller amountsmaller amount It isIt isdissolved by the solventdissolved by the solvent

EX: Salt waterEX: Salt water which is thewhich is thesolvent and the solute?solvent and the solute?

Solutions without waterSolutions without water

Many solutions are madeMany solutions are madewith solvents other thanwith solvents other than

waterwater

EXEX -- GasolineGasoline

A solution can be made ofA solution can be made of

any combination of gases,any combination of gases,

liquids or solidsliquids or solids

Particles in a solutionParticles in a solution

Whenever a solution forms,Whenever a solution forms,

particles of the solute leaveparticles of the solute leave

each other and becomeeach other and become

surrounded by particles ofsurrounded by particles of

the solvent.the solvent.

Ionic Solids in WaterIonic Solids in Water

Figure 4, pg. 82Figure 4, pg. 82--LL

Ions are attracted to polarIons are attracted to polarwater moleculeswater molecules

Water molecules surroundWater molecules surroundeach ion as it leaves theeach ion as it leaves thecrystalcrystal

Molecular Solids in WaterMolecular Solids in Water

Molecular solids break intoMolecular solids break intoindividualindividual neutralneutralparticlesparticles

when dissolved in water.when dissolved in water. Each particle is thenEach particle is then

surrounded by watersurrounded by watermoleculesmolecules

Solutions and ConductivitySolutions and Conductivity

Ionic compounds dissolvedIonic compounds dissolvedin water conduct electricityin water conduct electricity

EX: Salt waterEX: Salt water

Molecular compoundsMolecular compoundsdissolved in water do NOTdissolved in water do NOTconduct electricityconduct electricity

EX: Sugar waterEX: Sugar water


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ConcentrationConcentration

Dilute Solution:Dilute Solution: Only a littleOnly a littlesolute is dissolvedsolute is dissolved

Concentrated Solution:Concentrated Solution: MoreMore

solute is dissolvedsolute is dissolved

Concentration ExampleConcentration Example

Which is concentrated andWhich is concentrated andwhich is dilute?which is dilute?

SolubilitySolubility

Solubility:Solubility:A measure of howA measure of how

well a solute can dissolve inwell a solute can dissolve in

a solvent at a givena solvent at a given

temperaturetemperature

Saturated Solution:Saturated Solution: No moreNo more

solute can dissolve in thesolute can dissolve in the

solutionsolution

Unsaturated Solution:Unsaturated Solution: MoreMore

solute can dissolve in thesolute can dissolve in the

solutionsolution

Solubility can be used toSolubility can be used to

identify a compoundidentify a compound

Changing SolubilityChanging Solubility

Solubility changes whenSolubility changes when

conditions change.conditions change.

Temperature has a bigTemperature has a big

impact on the solubility of aimpact on the solubility of a

solutionsolution

Solids become less solubleSolids become less solubleas the temperature of theas the temperature of the

solventsolvent decreasesdecreases Gasses become less solubleGasses become less soluble

as the temperature of theas the temperature of thesolventsolvent increasesincreases


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Solutes lower the freeingSolutes lower the freeingtemperature of a solutiontemperature of a solution

and raise the boilingand raise the boiling

temperature of a solutiontemperature of a solution

EX: Salt in waterEX: Salt in water

Sharpen Your SkillsSharpen Your Skills

Turn to pg. LTurn to pg. L--8585 Complete the activity on aComplete the activity on a

piece of notebook paperpiece of notebook paper

Discover ActivityDiscover Activity

Turn to pg. 90Turn to pg. 90--LL

Complete the activity withComplete the activity with

your groupyour group

AcidsAcids

Acids share some commonAcids share some common

propertiesproperties

Taste sour, react withTaste sour, react with

metals and carbonates,metals and carbonates,

turn litmus paper red (oursturn litmus paper red (ours

yellow)yellow)

BasesBases

Bases share some commonBases share some commonproperties:properties:

Tastes bitter, slippery feel,Tastes bitter, slippery feel,do not react with metals,do not react with metals,turns litmus paper blueturns litmus paper blue(ours, too)(ours, too)

Acid FormulasAcid Formulas

Hydrochloric acidHydrochloric acid HClHCl

Nitric AcidNitric Acid HNOHNO33 Sulfuric AcidSulfuric Acid HH22SOSO44

Acetic AcidAcetic Acid HCHC22HH33OO22


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What do these have inWhat do these have incommon?common?

Acids are made of one orAcids are made of one or

more H atoms and onemore H atoms and one

negative ionnegative ion

Acids in SolutionsAcids in Solutions

Acids in water separate intoAcids in water separate intoH ions and negative ionsH ions and negative ions

WaterWater

HClHCl HH++ ++ ClCl--

An acid is any substanceAn acid is any substance

that produces H ions in waterthat produces H ions in water

Bases in a SolutionBases in a Solution

Many bases are made ofMany bases are made ofmetals combined withmetals combined withhydroxide ions (OHhydroxide ions (OH--))

Positive metal ions separatePositive metal ions separatefrom OHfrom OH-- when dissolved inwhen dissolved inwaterwater

A base is any substance thatA base is any substance thatproduces hydroxide ions inproduces hydroxide ions in

waterwater

WaterWater

NaOHNaOH NaNa++ + OH+ OH--

Not every base containsNot every base containshydroxide ions, but they ALLhydroxide ions, but they ALL

react with water to form OHreact with water to form OH--

ionsions

WaterWater

NHNH33 + H+ H22OO NHNH44++ + OH+ OH--


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Strengths of Acids and BasesStrengths of Acids and Bases

Acids and bases may beAcids and bases may bestrong or weakstrong or weak

Strength refers to how wellStrength refers to how well

the acid or base producesthe acid or base produces

ions in waterions in water

Measuring pHMeasuring pH

The concentration of H ionsThe concentration of H ionsis the key to how acidic oris the key to how acidic orbasic a solution isbasic a solution is

pH Scale:pH Scale:A range of valuesA range of valuesfrom 0 to 14 that expressesfrom 0 to 14 that expressesthe concentration of H ions inthe concentration of H ions ina solutiona solution

A low pH tells you that theA low pH tells you that theconcentration of H ions isconcentration of H ions ishighhigh

A high pH tells you that theA high pH tells you that theconcentration of H ions isconcentration of H ions islowlow

pH ScalepH Scale

pH lower than 7 = acidicpH lower than 7 = acidic

pH higher than 7 is basicpH higher than 7 is basic

Picture on pg. LPicture on pg. L--9999

Acid Base ReactionsAcid Base Reactions

When acids and bases react,When acids and bases react,

they produce a neutralthey produce a neutral

solutionsolution

EX: HCL +EX: HCL + NaOHNaOH HH22O +O +

NaNa++ ++ ClCl--

Called NeutralizationCalled Neutralization


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SaltsSalts

Salt:Salt:Any ionic compoundAny ionic compoundmade from the neutralizationmade from the neutralizationof an acid with a baseof an acid with a base

Made from the positive ion ofMade from the positive ion ofa base and the negative iona base and the negative ionof an acidof an acid

DigestionDigestion

Foods must be broken downFoods must be broken downinto simpler substances thatinto simpler substances that

your body can use for rawyour body can use for raw

materialsmaterials

Digestion:Digestion: Breaks downBreaks down

complex food molecules intocomplex food molecules into

smaller moleculessmaller molecules

Mechanical Digestion:Mechanical Digestion: Tears,Tears,grinds and mashes largegrinds and mashes largefood molecules into smallerfood molecules into smalleronesones

Chemical Digestion:Chemical Digestion: Food isFood isbroken down and changedbroken down and changed

into other compoundsinto other compounds

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