Section 1: Composition of Matter

Matter is anything that has mass and takes up space.  Matter can be divided into mixtures and pure substances.  A substance is a type of matter with a fixed composition that cannot be separated by physical means.  These pure substances are either elements or compounds.  An element is a substance made up of atoms with the same identity, such as gold, helium, and aluminum.  A compound has atoms of two or more elements combined, such as water (H20) and carbon dioxide (CO2).

A mixture is a material made up of two or more substances that can be separated by physical means.  Mixtures are characterized in two ways.  A heterogeneous mixture is a mixture in which different materials are easily identifiable and can be separated.  For example, a fruit salad is comprised of several different types of fruit.  A homogeneous mixture is one in which two or more substances are uniformly spread out so that you cannot see one separate from another, such as vinegar and saltwater.


  1. Define matter.
  2. Identify two examples of compounds.
  3. Compare a heterogenous mixture to a homogeneous mixture.

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