IMPURE SUBSTANCES: MIXTURES

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IMPURE SUBSTANCES MIXTURES
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PROPERTIES OF MIXTURES

• A mixture is a combination of two or more
  substances that are not chemically combined

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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.

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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.

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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.

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MIXTURES AND COMPOUNDS
Mixtures 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
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TYPES OF MIXTURES

• There are three types of mixtures
• Homogeneous mixtures Colloids
• Heterogeneous mixtures

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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)

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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 cant be seen as individual
  indentifiable entities
• Mixed as much finer level, not readily
  distinguished

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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

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COLLOIDS

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

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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)

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

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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.

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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 dont even scatter light.

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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

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• 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.

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• 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.

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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

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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.

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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

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HETEROGENEOUS MIXTURES

• You can distinguish the two or more phases.

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SOLUTIONS, SUSPENSIONS AND COLLOIDS
Solutions Suspensions Colloids
Uniformly dispersed More or less dispersed Intermediate dispersed
Single phase More phases More phases
Small particles Large particles that settle out Intermediate particles
Cant scatter light Scatter or block light Scatter light