The Nature of The Nature of SolutionsSolutions

Looks Pure…But It Ain’t!Looks Pure…But It Ain’t! Solutions are not pure – they are mixtures that look Solutions are not pure – they are mixtures that look

the same throughout. They are known as the same throughout. They are known as homogeneous mixtures because they have only homogeneous mixtures because they have only the one phase (appearance).the one phase (appearance).

Components of a SolutionComponents of a Solution A solution is typically composed of a solvent and a A solution is typically composed of a solvent and a

solute.solute. The The solventsolvent is the liquid in which the substances is the liquid in which the substances

are dissolved and the are dissolved and the solutesolute is the substance that is the substance that is being dissolved in the solvent.is being dissolved in the solvent.

When water is used as the solvent, we call it an When water is used as the solvent, we call it an aqueous solutionaqueous solution..

Mixing It UpMixing It Up SolubleSoluble – The ability of a substance to be – The ability of a substance to be

dissolved in a second substance. Usually dissolved in a second substance. Usually refers to a solid that dissolves in a liquid.refers to a solid that dissolves in a liquid.

InsolubleInsoluble – The inability of a substance to – The inability of a substance to be dissolved in a second substance. be dissolved in a second substance. (Again, it usually refers to a solid within a (Again, it usually refers to a solid within a liquid.)liquid.)

MiscibleMiscible – The ability of two liquids to – The ability of two liquids to dissolve within each other.dissolve within each other.

ImmiscibleImmiscible – The inability of two liquids to – The inability of two liquids to dissolve within each other.dissolve within each other.

Types of SolutionsTypes of Solutions Solids dissolved in Solids dissolved in

LiquidsLiquids Liquids dissolved in Liquids dissolved in

LiquidsLiquids Gases dissolved in Gases dissolved in

LiquidsLiquids Gases dissolved in Gases dissolved in

GasesGases Liquids dissolved in Liquids dissolved in

SolidsSolids Solids dissolved in Solids dissolved in

SolidSolid

What up holmes?!?!?!What up holmes?!?!?!

No More Please…I’m FullNo More Please…I’m Full SolubilitySolubility is the physical property of a substance is the physical property of a substance

describing how soluble or insoluble it is. It is the describing how soluble or insoluble it is. It is the mass of a solute that will dissolve in a given mass mass of a solute that will dissolve in a given mass of a solvent. The more solute that will dissolve in of a solvent. The more solute that will dissolve in a given amount of solvent, the greater the a given amount of solvent, the greater the solubility of that substance.solubility of that substance.

When the maximum amount of a solid or gaseous When the maximum amount of a solid or gaseous solute has been dissolved in a given volume of solute has been dissolved in a given volume of solvent at a given temperature, a solvent at a given temperature, a saturated saturated solutionsolution is obtained. If you continue to add more is obtained. If you continue to add more solute to the solution – the solute will remain solute to the solution – the solute will remain undissolved.undissolved.

Temperature & SolubilityTemperature & Solubility Different substances are affected by temperature when Different substances are affected by temperature when

it comes to how soluble they are.it comes to how soluble they are.

Solid SolutesSolid Solutes – For most solids, the solubility increases – For most solids, the solubility increases as the temperature increases but there are exceptions.as the temperature increases but there are exceptions.

Think of dissolving salt in hot water over cold water.Think of dissolving salt in hot water over cold water.

Gas SolutesGas Solutes – Gases tend to become less soluble as – Gases tend to become less soluble as the temperature increases. Heat makes the liquid the temperature increases. Heat makes the liquid particles move more vigorously and this allows the gas particles move more vigorously and this allows the gas molecules in the liquid to escape.molecules in the liquid to escape.

This holds importance to lakes and rivers when companies This holds importance to lakes and rivers when companies use them to dump pollution – the increase in temperature use them to dump pollution – the increase in temperature caused by the pollution lowers the amount of dissolved caused by the pollution lowers the amount of dissolved oxygen and asphyxiates the fish.oxygen and asphyxiates the fish.

Liquid SolutesLiquid Solutes – There is no trend for liquids as – There is no trend for liquids as temperature increases or decreases.temperature increases or decreases.

Those crazy liquids!!! No pattern…darn them!Those crazy liquids!!! No pattern…darn them!

Solubility & TemperatureSolubility & Temperature

Why Water Melts WitchesWhy Water Melts Witches Water dissolves many things – it is known Water dissolves many things – it is known

as the as the ““universal solventuniversal solvent”.”. Water is polar and it pulls apart the Water is polar and it pulls apart the

compound because the parts of the compound because the parts of the compound being dissolved are more compound being dissolved are more attracted to the charges of the water than attracted to the charges of the water than their own components.their own components.

Ionic compounds dissolve readily in water Ionic compounds dissolve readily in water for this reason.for this reason.

SolvationSolvation is the process by which ions are is the process by which ions are attracted to and surrounded by solvent attracted to and surrounded by solvent molecules. We use the term molecules. We use the term hydrationhydration if if the solvent used is water.the solvent used is water.

Covalent Compounds in Covalent Compounds in WaterWater

Covalent compounds may dissolve in water or they may not – Covalent compounds may dissolve in water or they may not – it depends on the make up of the molecule.it depends on the make up of the molecule.

If the molecule has a functional group attached to it or has If the molecule has a functional group attached to it or has atoms that have a significant difference in electronegativities atoms that have a significant difference in electronegativities then the molecule will be polar and will dissolve in water. This then the molecule will be polar and will dissolve in water. This can be seen with many of the alcohol molecules like ethanol.can be seen with many of the alcohol molecules like ethanol.

When this is the case, When this is the case, hydrogen bondinghydrogen bonding may occur in may occur in which there is an attraction between the partially positive which there is an attraction between the partially positive hydrogen of one molecule to the partially negative oxygen of hydrogen of one molecule to the partially negative oxygen of a neighboring molecule.a neighboring molecule.

If the molecule is composed of atoms that do not have a If the molecule is composed of atoms that do not have a significant difference in electronegativities then the molecule significant difference in electronegativities then the molecule will not dissolve in water – such is the case with gasoline.will not dissolve in water – such is the case with gasoline.

Applications of this Stuff!Applications of this Stuff!Hi…I’m a fancy-looking model hired to talk to you Hi…I’m a fancy-looking model hired to talk to you about the usefulness of…Oh no!…My coffee!…My about the usefulness of…Oh no!…My coffee!…My

shirt!…My modelling!!!shirt!…My modelling!!!

Getting Zestfully Clean!Getting Zestfully Clean! Soaps and detergents contain both polar Soaps and detergents contain both polar

and nonpolar parts.and nonpolar parts. The polar part (the head) of the molecule The polar part (the head) of the molecule

readily dissolves in water – we say it is readily dissolves in water – we say it is hydrophilichydrophilic..

The nonpolar part is a long hydrocarbon chain The nonpolar part is a long hydrocarbon chain (the tail) that does not dissolve in water – it is (the tail) that does not dissolve in water – it is hydrophobichydrophobic..

When the soap is placed in water, micelles When the soap is placed in water, micelles will form. These spherical structures allow will form. These spherical structures allow the hydrophilic heads to dissolve within the hydrophilic heads to dissolve within the water while allowing the hydrophobic the water while allowing the hydrophobic tails to hide from it.tails to hide from it.

Micelles and Soapy WaterMicelles and Soapy Water The micelles will quickly The micelles will quickly

form when the soap is form when the soap is placed in water.placed in water.

They do not clump They do not clump together as many of the together as many of the heads of the soap heads of the soap molecules are ionic and molecules are ionic and the like charges will the like charges will keep a little distance keep a little distance between neighbouring between neighbouring micelles. This ensures a micelles. This ensures a solution of sorts solution of sorts between the water and between the water and the soap. the soap.

Cleaning Your Act upCleaning Your Act up Soaps get stains out because Soaps get stains out because

the hydrophobic tails hide the hydrophobic tails hide from the awful water in the from the awful water in the dirt and grease of the stain.dirt and grease of the stain.

Your washer agitates the Your washer agitates the water which smashes the water which smashes the micelles against the stain micelles against the stain and spreads out the soap.and spreads out the soap.

The tails dig into the stain The tails dig into the stain and the same agitation pulls and the same agitation pulls against the hydrophilic head against the hydrophilic head and shakes the stain loose and shakes the stain loose bit by bit. The stain is gone bit by bit. The stain is gone and the dirt goes down the and the dirt goes down the drain.drain.

Stain out is good!Stain out is good!

The EndThe End