Two chemicals react to generate a new chemical in a combination reaction. A combination reaction is nearly always an exothermic reaction.
The combustion process is one example of a combination reaction.
When barium interacts with fluorine, however, Barium Flouride is formed, which is a highly exothermic reaction.
The reactions in which atoms or molecules combine to generate a product are known as combination reactions.
The majority of reactions involving combinations are exothermic.
For instance:
Magnesium oxide reacts with carbon dioxide to generate magnesium carbonate, releasing heat in the process because this is an exothermic reaction.
MgO + CO2 MgO + CO2 MgO + CO2 MgO + CO2 MgO + CO (CO3)2
Calcium oxide (quick lime) interacts with water to form calcium hydroxide and a lot of heat.
Ca(OH)2 + heat + CaO + H2O