Elements, Compounds, and Mixtures

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Introduction to Matter
Chapter 3
Elements, Compounds, and Mixtures
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Elements

• An element is a pure substance that cannot be
  separated into simpler substances by physical OR
  chemical means.
• Made of only ONE type of particle (ATOM).
• Have characteristic properties
• Physical melting point, boiling point, density,
  color,
• hardness, and texture.
• Chemical flammability and reactivity.
• THREE categories of elements
• Metals shiny, conductors of heat/electricity,
  malleable, ductile
• Nonmetals dull, nonconductors, nonmalleable,
  brittle
• Metalloids (semiconductors) characteristics of
  BOTH

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Compounds

• A compound is a pure substance composed of TWO or
  more elements that are chemically combined.
• Elements combine by reacting, or undergoing a
  chemical change, with one another.
• A particle of a compound is a molecule.
• Molecules are formed when atoms of two or more
  elements join together.
• As an element does, each compound has its own
  properties, but they differ from the elements
  that form it (sodium chlorine SALT).

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Sodium bicarbonate
Acetic acid
Calcium carbonate
Compounds
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Breaking down COMPOUNDS

• HEAT
• ELECTRICITY

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COMPOUNDS in Nature
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Mixtures

• A mixture is a combination of two or more
  substances that ARE NOT chemically combined.
• Pizza is a MIXTURE the cheese and tomato sauce
  do not react when they are mixed to make a pizza.
• NO chemical change happens when a mixture is made
  (each substance keeps its identity).
• Common ways to separate mixtures
• Picking
• Distillation boiling to separate
• Magnet
• Centrifuge spinning to separate

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Mixtures
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Separating Mixtures
Distillation
Centrifuge
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Solutions

• A mixture that appears to be a single substance.
• TWO parts
• Solvent does dissolving
• Solute gets dissolved
• Examples
• Air (oxygen in nitrogen)
• Soft drinks (CO2 in H2O)
• Antifreeze (alcohol in H20)
• Salt water (salt in water)
• Brass (zinc in copper)

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Concentrated or Dilute?
Solubility of a solute the ability of a solute
to dissolve in a solvent at a certain
temperature. How do you increase solubility?
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Suspension

• A suspension is a mixture in which particles of a
  material are dispersed throughout a liquid or gas
  but are large enough that they settle out.

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Colloid

• A colloid is a mixture in which the particles are
  dispersed throughout but are not heavy enough to
  settle.

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Classify that SUBSTANCE!
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