Unit 2

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Unit 2 Matter

• Classification of Matter
• Properties of Matter

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A. Matter Flowchart
MATTER
yes
no
Can it be physically separated?
Homogeneous Mixture (solution)
Heterogeneous Mixture
Compound
Element
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Pure Substances

• 1. Element
• composed of identical atoms
• EX copper wire, aluminum foil

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Pure Substances

• 2. Compound
• composed of 2 or more elements in a fixed ratio
• properties differ from those of individual
  elements
• EX table salt (NaCl)

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Mixtures

• Variable combination of 2 or more pure substances.

Homogeneous even distribution ( solutions)
Heterogeneous uneven distribution (suspensions
colloids)
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Mixtures

• 1. Solution
• homogeneous
• very small particles
• no Tyndall effect

• particles dont settle
• EX rubbing alcohol

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Mixtures

• 2. Colloid
• heterogeneous
• medium-sized particles
• Tyndall effect
• particles dont settle
• EX milk

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The Tyndall Effect
Colloids scatter light, making a beam visible.
Solutions do not scatter light.
Which glass contains a colloid?
colloid
solution
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Mixtures

• 3. Suspension
• heterogeneous
• large particles can see
• Tyndall effect
• particles settle
• (needs to be shaken)
• EX fresh-squeezed lemonade

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Mixtures

• Examples
• jello
• muddy water
• Fog
• saltwater
• Italian salad dressing

• colloid
• suspension
• colloid
• solution
• suspension

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Mixtures vs. Compounds

• Components may be in any proportion
• Individual components retain their own identities
• Components may be separated physically
• When mixture is formed there is little to no
  evidence of a reaction

• Components are in fixed proportions
• Individual components lose their identities, new
  set of properties result
• Components may be separated only chemically
• When compound is formed there is evidence of a
  reaction

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Physical Separation Techniques

• Difference in Densities (density column some
  objects float in others)
• Filtration (separate solids from liquids)
• Magnetism
• Chromatography
• Distillation (separation by boiling points)

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Separation of a Mixture
The constituents of the mixture retain their
identity and may be separated by physical means.
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Separation of a Mixture
The components of dyes such as ink may be
separated by paper chromatography.
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Separation of a Mixture
Distillation
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Types of Properties

• Physical
• Properties that describe the substance itself,
  rather than describing how it can change
• Example boiling point, color, size

• Chemical
• Properties that describe the substances ability
  to undergo changes that transform it into other
  substances
• Example charcoal has the ability to burn in air

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Types of Physical Properties
Extensive properties
depend on the amount of
matter that is present.
Volume
Mass
Energy Content (think Calories!)
Intensive properties
do not depend on the
amount of matter present.
Melting point
Boiling point
Density
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Changes in Matter

• Physical Change
• Change in form or state of matter without
  altering chemical composition
• Examples slicing a banana, boiling water,
  dissolving sugar

• Chemical Change
• Changing substance into new substance by
  reorganizing atomschemical bonds are made or
  broken
• Examples burning, rusting, copper turns green

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5 Indicators of a chemical change

• Color Change
• Light emitted (glow sticks, candle burning)
• Temperature change (happens on its own you
  dont supply heat)
• Precipitate forms (solid from 2 liquids)
• Gas production (you see bubbles)

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Three Phases
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Solids

• Definite shape/definite volume
• Molecules are tightly packed, but can still move
  slightly
• Most Dense state of matter (because particles are
  the closest)

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Liquids

• Definite volume/no definite shape (takes the
  shape of its container)
• Fluid because it flows
• Particles are not as close as solids, but are
  more dense than gases

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Gases

• No definite shape or volume
• Least dense of the 3 states of matter because the
  particles are far apart

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Which state of matter are they?
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Phase Differences
Solid definite volume and shape particles
packed in fixed positions.
Liquid definite volume but indefinite shape
particles close together but not in fixed
positions
Gas neither definite volume nor definite shape
particles are at great distances from one another
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Phase Changes

• Freezing (liquid to solid)
• Melting (solid to liquid)
• Evaporation (liquid to gas)
• Condensation (gas to liquid)
• Sublimation (solid to gas)
• Deposition (gas to solid)
• Phase changes are PHYSICAL changes!!!!