MixturesMixtures

Salt water

CoffeeSalad

dressing

Soda

Soup

Fog

A mixture is material made up of two or more substances that are not chemically

combined. Each substance in the mixture keeps its own properties.

Ex. salt water, pizza

Mixtures can be separated with physical processes. These include filtering,

separating by distillation (salt water) or machines such as the centrifuge (blood). Separation can also occur using density,

melting, freezing, and magnetism.

Mixtures do not always contain the same amounts of different substances.

(They do not have set ratios.)

Mixtures Compounds

can be made of elements, compounds, or both

made of elements

keep their original properties lose original properties

separated by physical means separated by chemical means

formed using any ratio of components

formed using a set mass ratio of elements (like H2O)

A solution is a mixture that appears to be a single substance but is made of particles of

two or more substances that are evenly mixed. The particles are so small they cannot be seen

and they never settle out.

Another name is a homogeneous mixture because they have the same appearance and

properties throughout. Ex. salt water, vinegar, cake, iced tea, stainless steel, brass.

The solute is the substance being dissolved (like sugar in coffee).

The solvent is the substance in which the solute

is dissolved (coffee).

Salt is the solute and water is the solvent in salt water.

Concentration is a measure of the amount of solute dissolved in a solvent. Concentration can be

expressed in grams of solute per milliliter of solvent.

Solutions can be described as concentrated (lots of solute) or dilute

(a little of solute).

A saturated solution contains all the solute it can at a given temperature.

An unsaturated solution contains less solute than it can hold at a given temperature. More solute can be

dissolved into an unsaturated solution.

A supersaturated solution is forced to contain more solute than its normal

saturation level.

Solutions can be saturated, unsaturated or supersaturated.

Solubility is the amount of solute needed to make a saturated solution given the

amount of solvent at a given temperature. Solubility is usually expressed in grams

per 100 mL of solvent. 

The solubility of KNO3 is

250 g at 100°C.

There are three methods to help solids dissolve faster including: mixing by stirring or shaking,

heating, and crushing.

Gases dissolve faster when they are cooled.

A suspension is a mixture where particles are throughout the liquid but are large

enough to settle out.

Ex. muddy water, salad dressing, some liquid medicines (“shake before using”).

Suspensions are heterogeneous mixtures because the different parts can be easily seen.

The particles are insoluble so they do not dissolve in liquid or gas.

The particles of a suspension are large and scatter or block light so they are

difficult to see through.

If it sits undisturbed, the particles will

settle out like a snow globe.

A suspension can separated with a filter.

A colloid is a heterogeneous mixture in which particles are spread throughout but are not heavy enough to settle out.

The particles are relatively small and fairly well mixed.

Ex. fog, jello, milk, smoke, mayonnaise, stick deodorant.

The particles of a colloid are smaller than a suspension, but these particles still scatter a

beam of light when shined through. A colloid cannot be separated with a filter.

The Tyndall effect is the scattering of light by particles in a mixture. The Tyndall effect can

be seen in all colloids. (Remember that colloids have invisible

particles that never settle out.)

Both the yellow and red liquids at left look all

the same.

The yellow solution does NOT scatter the

light, but the red colloid scatters the light.

Fog scatters light.

Smog is a form of air pollution. Smog is a colloid of small, invisible pieces of solid

materials mixed with the gases that make up air.

Smog has many natural causes like forest fires, volcanic eruptions, wind and dust. The major cause of smog today is the unburned

particles in automobile exhaust.

Other causes of smog:gasoline stations & industrial plants

hair sprays & spray paints wood-burning stoves & fireplaces

Solubility Graph Notes

Remember: on the line – saturated below the line – unsaturated above the line - supersaturated

1) How many grams of sodium chlorate dissolves at 60ºC? 160 g160 g2) At what temperature does 40g of sodium chloride dissolve? 80ºC80ºC3) Would 120g of potassium bromide at 80ºC form a saturated, unsaturated or supersaturated solution? supersaturatedsupersaturated4) Would 80g of sodium nitrate at 20ºC form a saturated, unsaturated or supersaturated solution? unsaturatedunsaturated