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Reactions in Chemistry



Chemical reactions are processes that occur when two or more atoms form chemical bonds or when chemical bonds between atoms break. Chemical reaction involves a rearrangement of electrons in the outermost shells of atoms. Molecular and ionic equations are used to describe chemical reactions. The reactants and products in a reaction must be balanced in atoms and their charge. There are millions of chemical reactions that take place every day, offering valuable insight into understanding the world. These types of chemical reactions include precipitation, redox, neutralization, combustion, synthesis, double and single displacement, and decomposition reactions.

At A Glance

  • Chemical reactions are processes in which the atoms of some substances are rearranged to obtain new, different substances.
  • To balance a chemical equation, both atoms and charge must be balanced. Balancing atoms can be done by following certain procedural steps.
  • In an ionic equation, ionic compounds are shown as positive and negative ions. Charges must be balanced on both sides of an ionic equation.
  • Addition reactions involve two or more reactants combining to form products. In decomposition reactions, a reactant decomposes into two or more products.
  • In oxidation-reduction reactions, the oxidation states of two or more atoms change.
  • In neutralization reactions, acids and bases react with one another, often forming salt and water.
  • In single-displacement reactions, an atom or a group of atoms from a reactant is replaced with another atom or group of atoms in the products. In double-displacement reactions, two reactants exchange atoms or groups.
  • A reaction may belong to several different categories.