1. Solutions, Suspensions and Colloids
A Matter of Fact
Solutions, Suspensions and Colloids

2. What is a Mixture?
Mixtures – two or more substances that are not chemically combined with each other and can be separated by physical means. The substances in a mixture retain their individual properties.
Two types:
Heterogeneous Mixtures (cereal, salad)
Homogeneous Mixture (paint)
Mixtures classified based on how well they are mied.
Heterogeneous Mixtures – substances in which components are not evenly mixed. Not chemically combined.
Ex: oil and vinegar salad dressing, salad, nut cereal.
Homogenous Mixtures – substances in which components are evenly mixed
Ex: paint, milk – chemically same thoroughout, toothpaste, perfume

4. Two types of Mixtures Mixtures Homogeneous Mixtures
Heterogeneous Mixtures
Solutions
Colloids
Alloys
Suspensions

5. Solutions
A type of homogeneous mixture formed when one substance dissolves in another.
It is the best mixed of all mixtures.
Same appearance and properties throughout
The particles are very small, never settle out,nnor can they be filtered out of these mixtures. The particles don’t scatter light.

6. Solvent and Solute
A solution always has a substance that is dissolved and a substance that does the dissolving.
Solute -substance that is dissolved
Solvent -substance that does the dissolving
Lemonade drink mix (solute) and the water (solvent)

7. Animation of NaCl dissolving in H2O
Dissolving a Salt.swf

8. Solutes
Insoluble: Unable to dissolve in the solvent
Soluble: Able to dissolve in the solvent

9. The Universal Solvent: Water

10. Water as a Solvent Many liquid solutions contain water as the solvent.
Ocean water is basically a water solution that contains many salts.
Body fluids are also
water solutions.

11. Concentration of a Solution
Concentration is a measure of how much solute is dissolved in the solvent.
Concentrated Orange Juice
Concentrated Laundry Detergent
Opposite of concentrated is dilute.

12. Solubility
The amount of solute that can dissolve in a given amount of solvent.
Example: What happens if you add a lot of sugar to a glass of iced tea?
Solubility of solids in liquids increases with temperature.
You can add more sugar to hot tea than iced tea.
Solubility of gases in liquids decreases with temperature.
You can keep more bubbles in cold soda than warm soda.
Taking our lemonade, if we add too much sugar to the lemonade, it may not all dissolve. Maximum amount of solute.

13. Speed up Dissolving? Mixing Heating Crushing
Smaller particles dissolve faster. Temperature increase, more easier to dissolve the solute.

14. Movie on solubility, solute, and solutions.

15. Solutions are made from solutes and solvents from all states of matter
Solutions are made from solutes and solvents from all states of matter. Example: Air is a solution of oxygen and other gases (solutes) dissolved in nitrogen (solvent).
All solutions do not have to be like the salt water or lemonade. It can be air too -> gas in a gas.

16. Types of solutions Solute Solvent Example Gas Gas
Air (oxygen in nitrogen)
Gas Liquid
Soda water
(CO2 in H2O)
Solid Liquid
Ocean water
(salt in water)
Solid Solid
Gold jewelry (copper in gold), brass, bronze, pewter, solder
Solutions do not have to be a solid and a liquid. It can be any combination of gas in a gas or gas in a liquid, or liquid in a liquid, or solid in liquid and solid in a solid (alloy)

17. Types of Solutions
Solute Solvent Example Liquid Gas Humid Air Liquid Liquid Antifreeze ethylene glycol in H2O Liquid Solid Dental fillings Hg in Ag Solid Gas Soot, dust in air

18. Metals dissolved in metals are called alloys.
Special solution in which metal dissolved in a metal- pewter, gold jewelery etc.
Stainless steel is a mixture
of iron and chromium.
Brass is an alloy of copper and zinc.

19. Movie on alloys

20. Suspensions Suspensions are mixtures containing large particles.
If you shake or stir a suspension, the particles will disperse, but will eventually settle out or separate.
Particles of a suspension will scatter light.
Heterogeneous mixture in which some particles settle out. Snow globe. Particles are insoluble (do not dissolve)
Examples: muddy water, salad dressing, snowglobe. Particles scatter light. Like in medicines -> need to shake well.
Can sepearate using filter, the larger particles stay.

21. Colloids
Colloids are mixtures containing relatively large particles that do not settle out.
The particles are dispersed throughout the mixture, but are not dissolved.
Particles of a colloid will scatter light.
Ex: Shaving, fog and smoke, gelatin. Light can pass through it and light can be seen
Cannot be separated by filtration. (like a solution)

22. Types of Colloids Gas Liquid FOAMS, whipped cream, mousse
Liquid            Gas                FOG, Clouds
Liquid            Liquid            EMULSIONS: Mayonnaise,oil,vinegar,egg yolk
Liquid            Solid              butter and other gels
Solid              Gas               SMOKES, all kinds
Solid              Liquid           SOLS, Paint pigment -many are metallic - in H2O or oil
Gas Solid Marshmallows

24. Separation Techniques
Magnets – based on magnetism of the matter
Centrifugation – based on densities of the matter
Ex: blood is broken down into red blood cells, platelets, plasma

25. Chromotography Means “Color Writing”
It involves passing a mixture dissolved in a mobile phase through a stationary phase.
Components travel at different speeds based on their size and therefore separate along the way.

26. Separation Techniques
The Distillation Process
Distillation is a process used to separate a mixture into components based on boiling points
Involves a change of state, usually from liquid to gas, and then condensation to return the now separated component to liquid state.
The distillation apparatus (still) has three parts: (1) A flask with an outlet tube, (2) A condenser, and (3) A vessel.

27. Distillation
Figure 1.13 A simple apparatus for the separation of a sodium chloride solution (salt water) into its components. Boiling the solution evaporates the water, which is condensed, then collected in the receiving flask. After all the water has boiled away, pure sodium chloride remains in the boiling flask.