1. IMPURE SUBSTANCES: MIXTURES

2. PROPERTIES OF MIXTURES
A mixture is a combination of two or more substances that are not chemically combined

3. PROPERTIES OF MIXTURES
No Chemical Changes in a Mixture No chemical changes happen when a mixture is made. So, each substance has the same chemical makeup it had before the mixture was formed.
Making a mixture is a
physical change.

4. PROPERTIES OF MIXTURES
Separating Mixtures Through Physical Methods Mixtures can be separated by using physical changes. Physical changes do not change the identities of the substances.
Some methods could be distillation, evaporation, filtration, dissolve, use of magnets, centrifugation,and chromatography.

6. PROPERTIES OF MIXTURES
The Ratio of Components in a Mixture The components of a mixture do not need to be mixed in a definite ratio.
For example, granite is a mixture of different minerals. Different ratios of the minerals give granite different colors, but the mixture is always called granite.

7. MIXTURES AND COMPOUNDS
Made of elements, compounds or both
Made of elements
No change in original properties of the components
Change the original properties of the components
Heat or electricity not required for separating the components
Heat or electricity required for separating the components
Made using any ratio of the components
Made using a fixed ratio of components

8. TYPES OF MIXTURES There are three types of mixtures:
Homogeneous mixtures Colloids
Heterogeneous mixtures

9. HETEROGENEOUS MIXTURES
The different components can be seen as individual substances. We can almost separate the components with our eyes.
The particles are visible (bigger particles)

10. HOMOGENEOUS MIXTURES Have the same composition throughout.
Any one region of the mixture has the same ratio of substance as any other region
The components can´t be seen as individual indentifiable entities
Mixed as much finer level, not readily distinguished

11. COLLOIDS
Is a mixture in which the particles are spread throughout but are not large enough to settle out
The particles are not as small as those of a solution, however are smaller than those of a suspension

12. COLLOIDS
Particles in a colloid are large enough to scatter light. A colloid cannot be separated by passing it through a filter.

13. COLLOIDS
Consists of two separated phases: Disperse phase (or internal phase) and a continuos phase (or dispersion medium).
May be solid, liquid or gas
Some are translucent because of the Tyndall Effect (which is the scattering of light)

14. Types of colloids Disperse phase Gas Liquid Solid Continuos phase None
Liquid aerosol Ex: fog, mist, hair spray
Solid aerosol Ex: cloud, smoke, air
Solid foam Ex:aerogel, styrofoam
Gel Ex: jelly, silicagel
Solid sol Ex: cranberry glass
Foam Ex: whipped cream, shaving cream
Emulsion Ex: milk, mayonnaise, hand cream
Sol Ex: blood

15. TYPES OF HOMOGENEOUS MIXTURES
SOLUTIONS (single phase)
A solution is a mixture that appears to be a single substance. The process in which particles of substances separate and spread evenly throughout a mixture is known as dissolving.
In a solution, the solute is the substance that is dissolved. The solvent is the substance in which the solute is dissolved.

16. TYPES OF HOMOGENEOUS MIXTURES
Examples of Solutions Liquid solutions include soft drinks, gasoline, and tap water. Solutions may also be gases, such as air.
Solutions may also be solids, such as steel. Alloys are solid solutions of metals or nonmetals dissolved in metals.

17. SOLUTIONS
Particles in Solutions The particles in solutions are so small that they never settle out. They also cannot be removed by filtering.
The particles in solutions are so small that they don’t even scatter light.

18. Concentration= amount of solute
SOLUTIONS
Concentrated or Dilute? Solutions can be described as being concentrated or dilute. But these two terms do not tell you the amount of solute that is dissolved.
Concentration= amount of solute
amount of solution

20. Solubility is the ability of a solute to dissolve in a solvent at a certain temperature. Depends on the attractions of solute particles for one another and attractions of solvent particles for one another.

21. Dissolving Gases in Liquids Gases become less soluble in liquids as the temperature is raised.
Dissolving Solids Faster in Liquids Three ways to make a solute dissolve faster are mixing the solution, heating the solution, and crushing the solute into smaller particles.

23. SOLUTIONS Unsaturated solution
A solution that has not reached the limit of solute that will dissolve
Saturated solution
A solution in which no more solute can be dissolved

24. TYPES OF HETEROGENEOUS MIXTURES
SUSPENSIONS
A suspension is a mixture in which particles of a material are dispersed throughout a liquid or a gas but are large enough that they settle out.
The particles in a suspension are large enough to scatter or block light. A suspension can be separated by passing it through a filter.

25. SUSPENSIONS
Different components are in different phase, such as solids in liquids or liquids in gases
It is necessary to shake the substance before using it

26. HETEROGENEOUS MIXTURES
You can distinguish the two or more phases.

27. SOLUTIONS, SUSPENSIONS AND COLLOIDS
Uniformly dispersed
More or less dispersed
Intermediate dispersed
Single phase
More phases
Small particles
Large particles that settle out
Intermediate particles
Can´t scatter light
Scatter or block light
Scatter light