A substance is a type of matter that has uniform properties.

  • A chemical substance is a form of matter that consists of molecules of the same composition and structure.
  • A substance cannot be separated into its chemical components without breaking the chemical bonds that hold them together.
  • Substances can be classified into two main categories:
    • Elements are made up of a single type of atom
    • Compounds are made up of two or more elements chemically bonded together.
  • The properties of a substance, such as melting point, boiling point, and density, can help identify the substance and distinguish it from others.
  • Chemical reactions involve the formation and breaking of chemical bonds, resulting in the transformation of one or more substances into different substances with new properties.