Pure Substances:
(Can be Elements or Compounds)
Atoms consist only of one type of element.
Molecules can consist of more than one type of element.
– Molecules can have only one type of atom (an element).
– Molecules can have more than one type of atom (a compound).
If a pure substance can be decomposed into something else,
then the substance is a compound.
Mixtures:
• If more than one atom, element, or compound are found
together, then the substance is a mixture.
• If matter is not uniform throughout, then it is a heterogeneous
mixture.
• If matter is uniform throughout, it is homogeneous (can be
mixture or pure )
Tests for Substances:
• If homogeneous matter can be separated by physical means,
then the matter is a mixture.
• If homogeneous matter cannot be separated by physical means,
then the matter is a pure substance.