Mixtures and Compounds

What are Mixtures and Compounds?

• Mixtures are heterogeneous forms of matter. Mixtures are composed of variable proportions of molecules and atoms.
• Compounds are homogeneous forms of matter. Their constituent elements (atoms and/or ions) are always present in fixed proportions (1:1).

Examples of mixtures:

• • soil
  • ocean water and other solutions
  • air
  • the cytosol of a cell

  Examples of compounds:

  • water (H₂O)
  • table salt (NaCl)
  • sucrose (table sugar, C₁₂H₂₂O₁₁)

Properties of Mixtures

• The composition of a mixture is variable.
• Each of its components retains its characteristic properties.
• Its components are easily separated.

Properties of Compounds

• The relative proportions of the elements in a compound are fixed.
• The components of a compound do not retain their individual properties. Both sodium and chlorine are poisonous; their compound, table salt (NaCl) is absolutely essential to life.
• It takes large inputs of energy to separate the components of a compound.