Aqueous SolutionsAqueous Solutions

Solution - a homogenous mixture Solution - a homogenous mixture mixed molecule by molecule.mixed molecule by molecule.

Solvent - the stuff that does the Solvent - the stuff that does the dissolving.dissolving.

Solute -the stuff that is dissolved.Solute -the stuff that is dissolved. Aqueous solution- a solution with Aqueous solution- a solution with

water as the solvent.water as the solvent.

Aqueous SolutionsAqueous Solutions

Water dissolves ionic solids and polar Water dissolves ionic solids and polar covalent solids best.covalent solids best.

The rule is “like dissolves like”The rule is “like dissolves like” Polar dissolves polar.Polar dissolves polar. Nonpolar dissolves nonpolar.Nonpolar dissolves nonpolar. Oil is non polar.Oil is non polar. Oil and water don’t mix.Oil and water don’t mix. Salt is ionic- salt water.Salt is ionic- salt water.

How Ionic solids dissolveHow Ionic solids dissolve

Called Called solvation.solvation. Water breaks the + and - charged Water breaks the + and - charged

pieces apart and surround them.pieces apart and surround them.

How Ionic solids dissolveHow Ionic solids dissolve

H HOH

H OH

HO

H HO

HHO

HH

O

HH

OH

H

O

HH

O

Solids will dissolve if the attractive Solids will dissolve if the attractive force of the water molecules is force of the water molecules is stronger than the attractive force stronger than the attractive force of the crystal.of the crystal.

If not the solids are insoluble.If not the solids are insoluble. Water doesn’t dissolve nonpolar Water doesn’t dissolve nonpolar

molecules because the water molecules because the water molecules can’t hold onto them.molecules can’t hold onto them.

The water molecule hold onto each The water molecule hold onto each other and separate from the polar other and separate from the polar molecules.molecules.

HydrationHydration

Water molecules chemically bonded to Water molecules chemically bonded to solid salt molecules.solid salt molecules.

These compounds have fixed amounts These compounds have fixed amounts of water.of water.

The water can be driven off by heating.The water can be driven off by heating.

CuSOCuSO44

..5H5H22OO CuSO CuSO44 + 5H + 5H22OO

Called copper(II)sulfate pentahydrate.Called copper(II)sulfate pentahydrate.

- heat

+ heat

ElectrolytesElectrolytes

Substances that conduct electricity Substances that conduct electricity when dissolved in water.when dissolved in water.

Must have charged particles that Must have charged particles that can move.can move.

Ionic compounds break into Ionic compounds break into charged ions.charged ions.

NaCl NaCl NaNa+ + + Cl+ Cl-- These ions can conduct electricity.These ions can conduct electricity.

Non electrolytesNon electrolytes

Non electrolytes do not conduct Non electrolytes do not conduct electricity when dissolved in water.electricity when dissolved in water.

Polar covalent molecules such as Polar covalent molecules such as methanol CH3OH don’t fall apart into methanol CH3OH don’t fall apart into ions when they dissolve.ions when they dissolve.

Weak electrolytes don’t fall completely Weak electrolytes don’t fall completely apart into ions.apart into ions.

Strong electrolytes do ionizes Strong electrolytes do ionizes completely.completely.

Mixtures that are NOT Mixtures that are NOT SolutionsSolutions

Suspensions are mixtures that slowly Suspensions are mixtures that slowly settle upon standing.settle upon standing.

Particles of a suspension are more Particles of a suspension are more than 100 times bigger.than 100 times bigger.

Can be separated by filtering.Can be separated by filtering. Colloids particles are between the Colloids particles are between the

size of a solid and that of a liquid.size of a solid and that of a liquid.