Chapters 22: SolutionsChapters 22: Solutions

Section 1: How Solutions FormSection 1: How Solutions Form

A. Solutions and Other MixturesA. Solutions and Other Mixtures

All matter is either a pure substance or a mixtureAll matter is either a pure substance or a mixture Types of mixturesTypes of mixtures

Homogeneous = Homogeneous = solutionsolution; ;

same composition throughoutsame composition throughout Heterogeneous = not the same Heterogeneous = not the same

composition throughoutcomposition throughout

Pure substancesPure substances ElementsElements CompoundsCompounds

B. SolutionsB. Solutions

Solution is a homogeneous mixtureSolution is a homogeneous mixture Made up of solute and solventMade up of solute and solvent

Solute = what is dissolvedSolute = what is dissolved Solvent = substance doing the dissolvingSolvent = substance doing the dissolving

Most common solvent?Most common solvent? Water! Why?Water! Why?

B. Solution ExamplesB. Solution Examples

KoolAidKoolAid

Unsweet teaUnsweet tea

Sweetened teaSweetened tea

SaltwaterSaltwater

C. DissolvingC. Dissolving

Molecules are constantly in motion Molecules are constantly in motion according to…according to… Kinetic Theory of MotionKinetic Theory of Motion

When particles collide, energy is When particles collide, energy is transferredtransferred

When ionic compounds dissolve in water, When ionic compounds dissolve in water, ions separate in solutionions separate in solution Example: NaCl in water becomes NaExample: NaCl in water becomes Na++ and Cl and Cl--

D. SolventsD. Solvents

Water is universal solvent Water is universal solvent b/c of its b/c of its polaritypolarity

If something can dissolve If something can dissolve in something else, it is said in something else, it is said to be to be solublesoluble

If it cannot dissolve, it is If it cannot dissolve, it is said to be said to be insolubleinsoluble

““Like dissolves like”Like dissolves like”

D. SolventsD. Solvents

NONPOLAR

NONPOLAR

POLAR

POLAR

““Like Dissolves Like”Like Dissolves Like”““Like Dissolves Like”Like Dissolves Like”

E. SolvationE. Solvation

Solvation – Solvation – the process of dissolvingthe process of dissolving

solute particles are separated and solute particles are separated and pulled into solutionpulled into solution

solute particles are surrounded by solute particles are surrounded by solvent particlessolvent particles

E. SolvationE. Solvation

DissociationDissociation separation of an separation of an ionic ionic

solidsolid into aqueous into aqueous ionsions

NaCl(s) Na+(aq) + Cl–(aq)

E. SolvationE. Solvation

StrongElectrolyte

Non-Electrolyte

solute exists asions only

- +

salt

- +

sugar

solute exists asmolecules

only

- +

acetic acid

WeakElectrolyte

solute exists asions and

molecules

F. Factors Affecting SolubilityF. Factors Affecting Solubility

Solubility = amount of a substance that will Solubility = amount of a substance that will dissolve in a liquiddissolve in a liquid

Smaller pieces of a substance dissolve Smaller pieces of a substance dissolve faster b/c of larger surface areafaster b/c of larger surface area

Stirring or shaking speeds dissolving b/c Stirring or shaking speeds dissolving b/c particles are moving faster and colliding particles are moving faster and colliding moremore

Heating speeds dissolving (see above)Heating speeds dissolving (see above) Not all substances dissolveNot all substances dissolve

F. SolubilityF. Solubility

Solids are more soluble at...Solids are more soluble at... high temperatures.high temperatures.

Gases are more soluble at...Gases are more soluble at... low temperatures &low temperatures & high pressures (Henry’s Law).high pressures (Henry’s Law). EXEX: nitrogen narcosis, the “bends,” soda: nitrogen narcosis, the “bends,” soda

G. SolubilityG. Solubility

Solubility CurvesSolubility Curves maximum grams of solute that will dissolve in maximum grams of solute that will dissolve in

100 g of solvent at a given temperature100 g of solvent at a given temperature varies with tempvaries with temp based on a saturated solnbased on a saturated soln

G. SolubilityG. Solubility

Solubility CurveSolubility Curve shows the shows the

dependence of dependence of solubility on solubility on temperaturetemperature

H. ConcentrationH. Concentration The more The more solutesolute or less or less solventsolvent in a in a

solution, the more solution, the more concentratedconcentrated the the solution becomessolution becomes

The less The less solutesolute or more or more solventsolvent in a in a solution, the more solution, the more dilutedilute the solution the solution becomesbecomes

A A saturatedsaturated solution is one in which no solution is one in which no more solute can dissolvemore solute can dissolve

A A supersaturatedsupersaturated solution is one in which solution is one in which the solvent is heated and can dissolve the solvent is heated and can dissolve more solutemore solute

H. ConcentrationH. Concentration

SATURATED SOLUTION

no more solute dissolves

UNSATURATED SOLUTIONmore solute dissolves

SUPERSATURATED SOLUTION

becomes unstable, crystals form

concentration

Chapter 23Chapter 23

Acids, Bases & SaltsAcids, Bases & Salts

Review – Acid NamesReview – Acid NamesHClHClHH22SOSO44

HNOHNO33

HH22SOSO33

HCHC22HH33OO22

Hydrochloric acidHydrochloric acidSulfuric acidSulfuric acidNitric acidNitric acidSulfurous acidSulfurous acidAcetic acidAcetic acid

What are acids?What are acids? Compounds that donate HCompounds that donate H++ ions in water ions in water Taste sourTaste sour Concentrated acids can burn skin and Concentrated acids can burn skin and

eyeseyes On pH scale, found below 7On pH scale, found below 7

Stronger acids closer to 1Stronger acids closer to 1 Examples: citric acid, stomach acid, soda, Examples: citric acid, stomach acid, soda,

coffeecoffee

What are bases?What are bases?

Compounds that donate OHCompounds that donate OH-- ions in water ions in water Taste bitter, are slipperyTaste bitter, are slippery Can be dangerous as wellCan be dangerous as well Often cleaning productsOften cleaning products pH above 7pH above 7

Stronger bases closer to 14Stronger bases closer to 14 Examples: bleach, baking Examples: bleach, baking

soda, antacidssoda, antacids

NeutralNeutral

All neutral solutions have a pH of 7All neutral solutions have a pH of 7

Water is a neutral solutionWater is a neutral solution

pH ScalepH Scale

NeutralizationNeutralization Reaction between an acid and a base to Reaction between an acid and a base to

produce water and a saltproduce water and a salt

HH++ + OH + OH-- H H22OO

Example:Example:

HCl + NaOH HCl + NaOH H H22O + NaClO + NaCl

Do not always produce a neutral solutionDo not always produce a neutral solution

IndicatorsIndicators

• Chemical dyes whose color are affected by acidic and basic solutions are called acid-base indicators

SummarySummary

electrolyteselectrolytes electrolyteselectrolytes

turn litmus redturn litmus red

sour tastesour taste

Donate HDonate H++ (HCl) (HCl) Donate OHDonate OH-- (NaOH) (NaOH)

turn litmus blueturn litmus blue

bitter tastebitter taste

vinegar, milk, soda, vinegar, milk, soda, apples, citrus fruitsapples, citrus fruits

ammonia, lye, antacid, ammonia, lye, antacid, baking sodabaking soda