Hydrogen and oxygen in elemental form combine to form water.
It is defined as a chemical reaction in which two or more substances combine to form a single substance under suitable conditions. Combination reactions involve the formation of new bonds and this process releases a large amount of energy in the form of heat.
- Formation of calcium oxide by the combination elements calcium and oxygen.
2Ca + O2 → 2CaO
- Formation of ammonia by the combination of elements nitrogen and hydrogen.
N2 + 3H2 → 2NH3