MATTER and CHANGE

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MATTER and CHANGE

• Read pp. 29-38 41-43 68-72 125-126 490-493

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Obj 1

• Pure substance matter that has a fixed
  (constant) composition and unique properties.
  Contains only 1 type element or compound
  homogeneous

• Mixture Contains at least 2 PHYSICALLY
• combined compounds can be homogeneous
• or heterogeneous

3
Obj 2 and 3 Homogeneous Substances

• Means same throughout
• 1) element only 1 type of atom
• compound 2 or more CHEMICALLY combined elements
  (not easily separated from each other)
• ex water, CO2
• Solution a special kind of mixture 2
  phases/parts (SOLUTE dissolves SOLVENT does the
  dissolving)
• ex moist air (H2O in Air) sterling
  silver (Cu
• in Agcalled an alloy)
• see p. 33 for other examples

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Heterogeneous matter

• Means different throughout
• Always a MIXTURE (solutions are mixtures that are
  NOT heterogeneous)
• 2 or more PHYSICALLY combined substances
  (elements/compounds)
• ex blood, air, muddy water

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• Matter can also be classified according to its
  composition. Mixtures can be homogeneous or
  heterogeneous.
• Mixtures can be separated into pure substances,
  and pure substances can be either compounds or
  elements.

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MATTER
Obj 7
Is it uniform throughout?
No
Yes
Heterogeneous mixture
Homogeneous
Can it be separated by physical means?
No
yes
Pure Substance
Homogeneous Mixture (solution)
Can it be decomposed into other substance by a
chemical process?
yes
No
Compound
Element
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Density (Dm/v)

• Units g/mL or g/cm3 (1mL1cm3)
• Depends on the identity of the substance NOT the
  amount of substance.
• Density of H20 1g/mL at 4oC

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Properties and Changes

• Physical PROPERTY can observe w/o changing the
  composition of a substance
• ex color, solubility, odor, hardness, density,
  melting pt., boiling pt.
• 2) Physical CHANGE when a substance changes its
  appearance but not its composition
• usually reversible
• ex change of state (water changing from
  solid--gt liquid--gt gas), painting wood

Obj 16
9

• Chemical PROPERTY the ability to form a new
  substance
• Chemical CHANGE changes the composition of the
  substance
• usually NOT reversible gives off/uses up energy
• ex burning, rotting, rusting, fermenting,
  exploding, corroding
• Remember Law of Conservation of Mass in any
  physical or chemical change, matter cannot be
  created or destroyed it may change forms, but it
  is conserved in every case

Obj 18
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4 classes of ELEMENTS

• Metals shiny, conduct electricity, malleable,
  ductile
• Nonmetals dull, dont conduct, brittle
• Metalloids properties of both
• Synthetics man-made elements in the laboratory

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2 types of COMPOUNDS

• Inorganic do not contain carbon ex NO2, H2O)
• Organic contain carbon ex CO2, CH4

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3 classes of MIXTURES
small
medium
large
No
yes
yes
No
No
yes
No
No
yes
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Physical Separation of Mixtures

• Distillation- according to boiling pt.

2) Filtration- according to size
3) Centrifugation- according to density

• 4) Chromatography- according to solubility

separation of compounds is different because it
involves CHEMICAL separation
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Your turn, answer the following

• Is it an element, compound or mixture?
• a. Water b. salt water
• c. Dirt d. air
• e. Helium f. carbon dioxide
• Name 3 ways to separate a mixture
• Name two types of pure substances.
• What is the density of water at room
  temperature?