WaterWater

Water in the Liquid StateWater in the Liquid State• A water molecule is polar.

Water in the Liquid StateWater in the Liquid State• Polar molecules are attracted to one another

by dipole interactions. The negative end of one molecule attracts the positive end of another molecule.

Water in the Liquid StateWater in the Liquid State• The intermolecular attraction among water

molecules results in the formation of hydrogen bonds.

Surface TensionSurface Tension

Water in the Liquid StateWater in the Liquid State• A surfactant is any substance that

interferes with the hydrogen bonding between water molecules and thereby reduces surface tension.

Water in the Liquid StateWater in the Liquid State– Vapor Pressure

• Hydrogen bonding between water molecules also explains water’s unusually low vapor pressure. Because hydrogen bonds hold water molecules to one another, the tendency of these molecules to escape is low, and evaporation is slow.

Water in the Solid StateWater in the Solid State

Water in the Solid StateWater in the Solid State

Homogeneous vs. Homogeneous vs. Heterogeneous MixturesHeterogeneous Mixtures

• Guided note, 3.

Homogeneous Heterogeneous

Mixture that is uniform in composition. Components are evenly distributed throughout the mixture and not easily distinguished.

Mixture that is not uniform in composition. Components are not evenly distributed throughout the mixture

Solvents and SolutesSolvents and SolutesGuided note: 4.Guided note: 4.

Solvent Dissolving medium in a solution

Solute Dissolved particles in a solution

Solutionhomogeneous mixture, consisting of a solute dissolved in a solvent

The Solution ProcessThe Solution Process• Guided note: 7. The dissolving process is a result of

random molecular motion.• The process by which the positive and negative ions of an ionic

solid become surrounded by solvent molecules is called solvation.

Solution FormationSolution Formation• The compositions of the solvent and the

solute determine whether a substance will dissolve.

•Guided notes: 8. The factors that determine how fast a substance dissolves are

»stirring (agitation)»temperature»the surface area of the dissolving

particles

Solubility – SaturationSolubility – SaturationGuided Notes – 9.Guided Notes – 9.

Saturated Solution UnSaturated Solution

contains the maximum amount of solute for a given quantity of solvent at a given temperature and pressure.

contains the maximum amount of solute for a given quantity of solvent at a given temperature and pressure.

SolubilitySolubility

Solubility - ExpressionSolubility - ExpressionGuided Note: 9. Solubility definition– Solubility is often expressed in grams of

solute per 100 g of solvent at a specific temperature and pressure to produce a saturated solution.

16.1

Factors Affecting SolubilityFactors Affecting SolubilityGuided note: 10.Guided note: 10.

– Temperature affects the solubility of solid, liquid, and gaseous solutes in a solvent;

– Both temperature and pressure affect the solubility of gaseous solutes.

Temperature vs. SolubilityTemperature vs. Solubility

SupersaturationSupersaturation• A supersaturated solution contains more

solute than it can theoretically hold at a given temperature. (Guided notes, 9.)

• The crystallization of a supersaturated solution can be initiated if a very small crystal, called a seed crystal, of the solute is added.

Factors Affecting SolubilityFactors Affecting Solubility– Pressure

• Changes in pressure have little effect on the solubility of solids and liquids, but pressure strongly influences the solubility of gases.

• Gas solubility increases as the partial pressure of the gas above the solution increases.

Factors Affecting SolubilityFactors Affecting Solubility• Henry’s law states that at a given

temperature, the solubility (S) of a gas in a liquid is directly proportional to the pressure (P) of the gas above the liquid.

Strong ElectrolytesStrong Electrolytes

• Guided note: 5. An strong electrolyte is a compound that conducts an electric current when it is in an aqueous solution or in the molten state. – All ionic compounds

are electrolytes because they dissociate into ions.

Weak ElectrolytesWeak Electrolytes

• A weak electrolyte conducts electricity poorly because only a fraction of the solute in the solution exists as ions.

NonelectrolytesNonelectrolytes

• A compound that does not conduct an electric current in either aqueous solution or the molten state is called a nonelectrolyte.

Suspensions and ColloidsSuspensions and Colloids• A suspension is a mixture from which

particles settle out upon standing. – A suspension differs from a solution

because the particles of a suspension are much larger and do not stay suspended indefinitely.

• Colloids have particles smaller than those in suspensions and larger than those in solutions.

ColloidsColloids

ColloidsColloids

ColloidsColloids