13. TYPES OF MIXTURES!
There are three families of mixtures: solutions,
suspensions and colloids. Solutions are
homogeneous while suspensions and colloids are
heterogeneous.
14. SOLUTION!
• Solutions are homogeneous mixtures that contain a solute dissolved
in a solvent, e.g. salt dissolved in water. When the solvent is water, it
is called an aqueous solution. The ratio of mass of the solute to the
solvent is called the concentration of the solution.
• Solutions can be liquid, gaseous or even solid. Not only that, the
individual components of the solution can be different states of
matter. The solute assumes the phase (solid, liquid or gaseous) of the
solvent when the solvent is the larger fraction of the mixture.
15. GASEOUS SOLUTION!
• When the solvent is a gas, it is only
possible to dissolve gaseous solutes in it.
The most common example of a gaseous
solution is the air in our atmosphere,
which is nitrogen (the solvent) and has
solutes like oxygen and other gases.
16. LIQUID SOLUTIONS!
• Liquid solvents are capable of dissolving any type of solutes.
• Gas in liquid: Examples include oxygen in water, or carbon dioxide in
water.
• Liquid in liquid: Example include alcoholic beverages; they are
solutions of ethanol in water.
• Solid in liquid: Sugar or salt solutions in water are examples of such
mixtures. Many solid in liquid mixtures are not homogeneous so
they aren't solutions. They could be colloids or suspensions.
17. SOLID SOLUTIONS!
• Solid solvents can also dissolve solutes of any state of matter.
• Gas in solid: An example of this is hydrogen dissolved in
palladium
• Liquid in solid: Examples of this include mercury in gold,
forming an amalgam, and water (moisture) in salt
• Solid in solid: Alloys like steel, brass or bronze are an example
of such mixtures.
18. SUSPENSIONS!
• A suspension is a heterogeneous mixture that contains
solid particles that are large enough for sedimentation.
The solid particles do not dissolve in the solvent but are
suspended and freely floating. They are bigger than 1
micrometer and are usually large enough to be visible to
the naked eye. An example is sand in water. A key
feature of suspensions is that the suspended particles
settle over time if left undisturbed.
19. COLLOIDS!
• Colloids are heterogeneous like suspensions but
visually appear to be homogeneous because the
particles in the mixture are very small—1
nanometer to 1 micrometer. The difference
between colloids and suspensions is that the
particles in colloids are smaller and that the
particles will not settle over time.
20. HOW DO COMPUNDS AND MIXTURE
DIFFER?
•Thesubstancesthatmakeupamixturearenotchemically
bonded.
•Mixing is aphysicalchange.Thesubstancesthatexist
beforemixingstill existinthemixture.
22. COMPOUNDSDONOTKEEPTHEIRPROPERTIES
•Theproperties of a compound can bedifferent from the properties of
the elementsthatmakeitup.
•Sodium and chlorine bond and form table salt. Sodium is a soft,
opaque, silvery metal. Chlorine is a greenish, poisonous gas. Y
ou
cannotobserve anyoftheseproperties intablesalt.
