Solutions & Other Mixtures

Heterogeneous Mixtures

Amount of each substance in different samples of mixture varies

Suspensions

Heterogeneous mixture in which particles of a substance are more

or less evenly distributed throughout a liquid or gasParticles in a

suspension are large and will

eventually settle out

Particles in a suspension may be filtered out

Can classify a mixture as a

suspension if the particles settle

out or can be filtered out

Some mixtures of two liquids will separate:Liquids are immiscible

Ex.- oil and vinegar

Particles in a colloid are too small to settle out

Particles in a colloid are smaller than

those in suspensions: pass through

filters and remain suspended

Examples of colloids:Egg whites

Blood plasmaWhipped creamMarshmallows

FogSmoke

Some immiscible liquids can form colloids

Emulsion: a colloid in which liquids that normally do not mix are dispersed throughout each other

Homogeneous Mixtures

Individual components of the mixture too small to be seen; uniform mixture

Homogeneous mixtures are solutions

Solution: homogeneous mixture of one or more substances uniformly dispersed among similar particles of another substance

Solute: substance that does the dissolving

Solvent: substance in which the solute dissolves

Miscible liquids mix to form solutions

Can separate miscible liquids through process of distillation

Liquid solutions sometimes contain no water

Examples: gasoline, crude oil, paint stripper, diesel fuel, kerosene

Other states of matter can also form solutions

Examples: Air

VinegarSoft Drinks

Dental amalgam

Solids can dissolve in other solids

Alloys: homogeneous mixture usually composed of two or more metals

Dissolving depends on forces between particles

Rule of thumb in chemistry: like dissolves like

Polar dissolves polar:Water dissolves sugar

Nonpolar dissolves nonpolar:Paint thinner dissolves paint

The Dissolving Process

Solutes with a larger surface area dissolve faster

Solutes dissolve faster when the solvent is hot

Stirring or shaking a solution helps the solute dissolve faster

Solubility & Concentration

Solubility in Water

Solubility: the maximum amount of a solute that will dissolve in a given quantity of solvent

at a given temperature and pressure

Different substances have

different solubilitiesConcentration:

quantity of solute dissolved in a given volume of

solutionConcentrated

Dilute

Unsaturated solutions can dissolve more solute

At some point, most solutions become saturated with solute(s)

Saturated solution

Heating a saturated solution usually dissolves more solute

Temperature and pressure affect the solubility of gases

As temperature increases, gas solubility decreases

As pressure increases, gas solubility increases