Chemical reactions result in the production of new substances.

Matter is conserved as reactants bonds are broken and particles rearranged and new bonds formed to produce new chemicals.

Chemical signs indicate that a reaction has occurred. Such signs include

  • a permanent color change
  • the production of a gas
  • the appearance or disappearance of an insoluble solid
  • the production of light and heat

Chemical reactions are also generally difficult to reverse.

Chemical reactions can be classified or grouped together into various types. Some of these groups overlap.

What is a physical change?

What is a chemical change?

What is a word equation?