Chemical Reactions

What are the reactants and products of a chemical reaction?

In chemical reactions, substances known as reactants change into different substances called products:

• There are six main types of chemical reactions: synthesis, combustion, decomposition, single displacement, double displacement, and acidglossary term (opens in a new window)-baseglossary term (opens in a new window).
• In a synthesis reactionglossary term (opens in a new window), two or more reactants combine, forming a single productglossary term (opens in a new window) that is more complex than either of the reactants.
• The general formula for a synthesis reaction is A + B → AB.
• A decomposition reactionglossary term (opens in a new window) occurs when a single compound breaks down into two or more simpler substances.
• The general formula for a decomposition reaction is AB → A + B.
• In a combustion reactionglossary term (opens in a new window), heat is produced when oxygen and one or more other compounds combine.
• Combustion often forms water and carbon dioxide.
• A single displacement reactionglossary term (opens in a new window) occurs when one element replaces another element in a compound.
• The general formula for a single displacement reaction is A + BX → AX + B.
• In a double displacement reactionglossary term (opens in a new window), two compounds interchange elements to form two new compounds.
• The general formula for a double displacement reaction is AX + BY → AY + BX.
• In an acid-baseglossary term (opens in a new window) reaction, an acid and a base combine in a special kind of double displacement reaction. This process often forms water and ionic salt.
• Chemical reactions must obey the law of conservation of matter (or conservation of mass); no atoms are created or destroyed.
• A chemical equation shows the reactantglossary term (opens in a new window) on the left and resulting product on the right.
• All chemical equations must be balanced, meaning that the same number of atoms must appear on each side of the equation.