Solutions Solutions

DefinitionsTypes of SolutionSolutions, Colloids, SuspensionsProcess of DissolvingRate of SolutionConcentrationSolubility

DefinitionsDefinitions

Homogenous Mixture – two or more substances which have the same composition throughout; uniform; in the same state of matter

• Solutions, Colloids, Suspensions Heterogeneous Mixture – two or more

substances which have a mixture in which the ingredients are not uniformly dispersed.

• Fruity Pebbles

Definitions Definitions

Solution - Solution - homogeneous mixture of two or more substances

Solvent Solvent - present in greater amount

Solute Solute - substance being dissolved, present in smaller amount Solute

particles very small

Definitions Definitions

Solute Solute - KMnO4 Solvent Solvent - H2O

Hydrogen Bonds Attract Polar Water Molecules

Hydrogen Bonds Attract Polar Water Molecules

Types of Solutions Types of Solutions

Based on state of solvent. All solid-liquid-gas combos are

possible. EX: dental amalgam (alloy of silver,

mercury, etc.)• liquid solute, solid solvent• solid solution

Types of SolutionsTypes of Solutions

air O2 gas and N2 gas gas/gas

soda CO2 gas in water gas/liquid

seawater NaCl in water solid/liquid

brass copper and zinc solid/solid

Learning Check SF1Learning Check SF1

(1) element (2) compound (3) solution

A. water 1 2 3

B. sugar 1 2 3

C. salt water 1 2 3

D. air 1 2 3

E. tea 1 2 3

Solution SF1Solution SF1

(1) element (2) compound (3) solution

A. water 2

B. sugar 2

C. salt water 3

D. air 3

E. tea 3

Learning Check SF2Learning Check SF2

Identify the solute and the solvent.

A. brass: 20 g zinc + 50 g copper

solute = 1) zinc 2) copper

solvent = 1) zinc 2) copper

B. 100 g H2O + 5 g KCl

solute = 1) KCl 2) H2O

solvent = 1) KCl 2) H2O

Solution SF2Solution SF2

A. brass: 20 g zinc + 50 g copper

solute = 1) zinc solvent = 2) copper

B. 100 g H2O + 5 g KCl

solute = 1) KCl

solvent = 2) H2O

Dissolving Dissolving

SolvationSolvation

• occurs at the surface of the solute

• solvent particles surround solute particles (+/- attraction)

• solute particles are pulled into solution

Dissolving Dissolving

NaCl dissolving in waterNaCl dissolving in water

“Like Dissolves Like” “Like Dissolves Like”

NONPOLAR

NONPOLAR

POLAR

POLAR

DetergentsDetergents• polar “head” with long nonpolar “tail”• can dissolve both types

Learning Check SF4Learning Check SF4

Which of the following solutes will dissolve in water? Why?

1) Na2SO4

2) gasoline

3) I2

4) HCl

Like dissolves likeLike dissolves like

A ____________ solvent such as water is needed

to dissolve polar solutes such as sugar and

ionic solutes such as NaCl.

A ___________solvent such as hexane (C6H14)

is needed to dissolve nonpolar solutes such

as oil or grease.

Solution SF4Solution SF4

Which of the following solutes will dissolve in water? Why?

1) Na2SO4 Yes, polar (ionic)

2) gasoline No, nonnpolar

3) I2 No, nonpolar

4) HCl Yes, Polar

ColloidsColloids

Have medium size particles

Cannot be filtered

Separated with semipermeable membranes

Scatter light

(Tyndall effect)

Examples of ColloidsExamples of Colloids

Fog

Whipped

cream

Milk

Cheese

Blood plasma

Pearls

SuspensionsSuspensions

Have very large particles

Settle out

Can be filtered

Must stir to stay suspended

Examples of SuspensionsExamples of Suspensions

Blood platelets

Muddy water

Rate of Solution - SolidsRate of Solution - Solids

Solids dissolve faster (have greater solubility) with...Solids dissolve faster (have greater solubility) with...

• more stirring

• small particle size(increased surface area)

• high temperature

Temperature and Solubility of SolidsTemperature and Solubility of Solids

Temperature Solubility (g/100 g H2O) KCl(s) NaNO3(s)

0° 27.6 74 20°C 34.0 88 50°C 42.6 114100°C 57.6 182

The solubility of most solids (decreases or increases ) with an increase in the temperature.

Temperature and Solubility of SolidsTemperature and Solubility of Solids

Temperature Solubility (g/100 g H2O)

KCl(s) NaNO3(s)

0° 27.6 74

20°C 34.0 88

50°C 42.6 114

100°C 57.6 182

The solubility of most solids increases with an increase in the temperature.

Rate of Solution - GasesRate of Solution - Gases

Gases dissolve faster and have great Gases dissolve faster and have great solubility if...solubility if...

• no shaking or stirring

• high pressure above surface

• low temperature

Temperature and Solubility of GasesTemperature and Solubility of Gases

Temperature Solubility (g/100 g H2O)

CO2(g) O2(g)

0°C 0.34 0.0070 20°C 0.17 0.0043 50°C 0.076 0.0026

The solubility of gases (decreases or increases) with an increase in temperature.

Temperature and Solubility of GasesTemperature and Solubility of Gases

Temperature Solubility(g/100 g H2O)

CO2(g) O2(g)

0°C 0.34 0.0070

20°C 0.17 0.0043

50°C 0.076 0.0026

The solubility of gases decreases with an increase in temperature.

ConcentrationConcentration

Concentrated solutionConcentrated solution • large amount of solute

Dilute solutionDilute solution • small amount of solute

ConcentrationConcentration

% by Volume% by Volume: usu. liquid in liquid• EX: 10% juice = 10mL juice + 90mL

water

% by Mass% by Mass: usu. solid in liquid• EX: 20% NaCl = 20g NaCl + 80g water• % solution = mass of solute x 100

mass of solution

ConcentrationConcentration

SATURATED SOLUTION

no more solute dissolves

UNSATURATED SOLUTIONmore solute dissolves

SUPERSATURATED SOLUTION

becomes unstable, crystals form

concentration

SolubilitySolubility

SolubilitySolubility• maximum grams of solute that will

dissolve in 100 g of solvent at a given temperature

• varies with temperature• based on a saturated solution

g of solute 100 g water

Learning Check S1Learning Check S1

At 40C, the solubility of KBr is 80 g/100 g H2O.

Indicate if the following solutions are

(1) saturated or (2) unsaturated

A. ___60 g KBr in 100 g of water at 40C

B. ___200 g KBr in 200 g of water at 40C

C. ___25 KBr in 50 g of water at 40C

Solution S1Solution S1

At 40C, the solubility of KBr is 80 g/100 g H2O.

Indicate if the following solutions are

(1) saturated or (2) unsaturated

A. 2 Less than 80 g/100 g H2O

B. 1 Same as 100 g KBr in 100 g of water

at 40C, which is greater than its solubility

C. 2 Same as 60 g KBr in 100 g of water,

which is less than its solubility