Working with the Properties & Changes of Matter

  1. Working with the Properties & Changes of Matter

    • Chemical- any substance that has defined composition
    • Everything you see is made up of chemicals
    • Even things you cannot see are made up of chemicals
    • Some exist naturally
    • Some are manufactured
    • Chemical Reaction- the process by which one or more substances change to produce one or more different substances

  1. Physical States of Matter

    • Type and arrangement of particles in a sample of matter determine the properties of the matter

    • Most matter is one of the three states of matter

A. Properties of the Physical State
Solids- fixed volume and shape
Rigid structure
Liquids- fixed volume and variable shape
Takes shape of container
Gases- neither fixed volume or shape
Particles move independently
Will fill any container they occupy
  1. Changes of Matter

Many changes of matter happen. Changes occur in two different ways:
    • Physical Changes

    • Chemical Changes

A. Physical Change
Changes in which the identity of a substance doesn’t change
-Changes state
B. Chemical Changes
Identifies of substances change and new substances form.
Mercury (II) oxide mercury + oxygen

Reactants Products

-Substance or molecule that -Substance that forms in a chemical
participates in a chemical reaction reaction
Atoms are not destroyed or created, so mass does not change during a chemical reaction.

C. Evidence of Chemical Change

Generally, evidence that a chemical change may be happening falls into one of four categories; you may observe more than one.
  1. Evolution of a gas- the production of a gas is often observed by bubbling or by a change in color
  2. Formation of a Precipitate- when two clear solutions are mixed and become cloudy, a solid precipitate has formed
  3. Release or Absorption of Energy- change in temperature of the giving off of light energy are signs of energy transfer
  4. Color Change in the Reaction System- look for a different color when two chemicals react
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